- Prometheus: Climate Change Archives

Contents:

August 03, 2008

Joel Achenbach on Weather Extremes

In today's Washington Post Joel Achenbach has a smart and nuanced piece on weather extremes and climate change. The attribution of weather events and trends to particular causes is difficult and contested.

Equivocation isn't a sign of cognitive weakness. Uncertainty is intrinsic to the scientific process, and sometimes you have to have the courage to stand up and say, "Maybe."

For Achenbach's efforts he gets called stupid and a tool of the "deniers". Such complaints are ironic given that Achenbach explains how foolish it is to put too much weight on extreme events in arguments about climate change:

the evidence for man-made climate change is solid enough that it doesn't need to be bolstered by iffy claims. Rigorous science is the best weapon for persuading the public that this is a real problem that requires bold action. "Weather alarmism" gives ammunition to global-warming deniers. They're happy to fight on that turf, since they can say that a year with relatively few hurricanes (or a cold snap when you don't expect it) proves that global warming is a myth. As science writer John Tierney put it in the New York Times earlier this year, weather alarmism "leaves climate politics at the mercy of the weather."
There's an ancillary issue here: Global warming threatens to suck all the oxygen out of any discussion of the environment. We wind up giving too little attention to habitat destruction, overfishing, invasive species tagging along with global trade and so on. You don't need a climate model to detect that big oil spill in the Mississippi. That "dead zone" in the Gulf of Mexico -- an oxygen-starved region the size of Massachusetts -- isn't caused by global warming, but by all that fertilizer spread on Midwest cornfields.

Some folks may actually get the notion that the planet will be safe if we all just start driving Priuses. But even if we cured ourselves of our addiction to fossil fuels and stabilized the planet's climate, we'd still have an environmental crisis on our hands. Our fundamental problem is that -- now it's my chance to sound hysterical -- humans are a species out of control. We've been hellbent on wrecking our environment pretty much since the day we figured out how to make fire.

This caused that: It would be nice if climate and weather were that simple.

And the U.S. Climate Change Science Program recently issued a report with the following conclusions:

1. Over the long-term U.S. hurricane landfalls have been declining.
2. Nationwide there have been no long-term increases in drought.

3. Despite increases in some measures of precipitation , there have not been corresponding increases in peak streamflows (high flows above 90th percentile).

4. There have been no observed changes in the occurrence of tornadoes or thunderstorms.

5. There have been no long-term increases in strong East Coast winter storms (ECWS), called Nor’easters.

6. There are no long-term trends in either heat waves or cold spells, though there are trends within shorter time periods in the overall record.

In the climate debate, you would have to be pretty foolish to allow any argument to hinge on claims about the attribution of observed extreme events to the emissions of greenhouse gases. But as we've noted here on many occasions, for some the climate debate is a morality tale that cannot withstand nuance, even if that nuance is perfectly appropriate given the current state of understandings. But given the public relations value of extreme events in the climate debate, don't expect Achenbach's reasoned view to take hold among those calling for action. Like the Bush Administration and Iraqi WMDs, for some folks sometimes the intelligence that you wish existed trumps the facts on the ground.

August 01, 2008

The New Abortion Politics

The deepest pathologies in the climate policy debate can been seen in this comment in today's NYT column by Paul Krugman:

The only way we’re going to get action [on climate change], I’d suggest, is if those who stand in the way of action come to be perceived as not just wrong but immoral.

This strategy of characterizing one's political opponents as immoral is of course is part and parcel of the debate over abortion (which is why I call such politics "abortion politics" in The Honest Broker). In the climate debate the litmus test for having the proper morality (i.e., defined as not "standing in the way of action," by being a "denier" or "delayer" or [insert derisive moral judgment here]) is by holding and expressing (and not questioning) certain acceptable beliefs, such as:

*Not questioning any consensus views of the IPCC (in any working group)

*Not supporting adaptation

*Not emphasizing the importance of significant technological innovation

*Not pointing out that policies to create higher priced energy are a certain losing strategy

Deviation for these beliefs is, blasphemy -- heresy! Or as Paul Krugman recommends . . . immoral.

Climate change is the new locus of the U.S. culture wars. Unlike the abortion issue which was turned into a referendum on morality by the political right, the climate issue is fast becoming a referendum on morality by the political left. You couldn't make this stuff up.

Posted on August 1, 2008 09:44 AM View this article | Comments (2)
Posted to Author: Pielke Jr., R. | Climate Change | Science + Politics | The Honest Broker

July 31, 2008

Ocean Encroachment in Bangladesh

My first reaction upon seeing this story was that someone was having some fun. But it doesn't seem like benthic bacteria . . . So this article from the AFP comes as a surprise, and a reminder that forecasting the future remains a perilous business. With news like this, it seems premature to dismiss skepticism about climate science as fading away, far from it, expect skeptics of all sorts to have a bit more bounce in their steps.

DHAKA (AFP) - New data shows that Bangladesh's landmass is increasing, contradicting forecasts that the South Asian nation will be under the waves by the end of the century, experts say.
Scientists from the Dhaka-based Center for Environment and Geographic Information Services (CEGIS) have studied 32 years of satellite images and say Bangladesh's landmass has increased by 20 square kilometres (eight square miles) annually.

Maminul Haque Sarker, head of the department at the government-owned centre that looks at boundary changes, told AFP sediment which travelled down the big Himalayan rivers -- the Ganges and the Brahmaputra -- had caused the landmass to increase.

The rivers, which meet in the centre of Bangladesh, carry more than a billion tonnes of sediment every year and most of it comes to rest on the southern coastline of the country in the Bay of Bengal where new territory is forming, he said in an interview on Tuesday.

The United Nations Intergovernmental Panel on Climate Change (IPCC) has predicted that impoverished Bangladesh, criss-crossed by a network of more than 200 rivers, will lose 17 percent of its land by 2050 because of rising sea levels due to global warming.

The Nobel Peace Prize-winning panel says 20 million Bangladeshis will become environmental refugees by 2050 and the country will lose some 30 percent of its food production.

Director of the US-based NASA Goddard Institute for Space Studies, professor James Hansen, paints an even grimmer picture, predicting the entire country could be under water by the end of the century.

But Sarker said that while rising sea levels and river erosion were both claiming land in Bangladesh, many climate experts had failed to take into account new land being formed from the river sediment.

"Satellite images dating back to 1973 and old maps earlier than that show some 1,000 square kilometres of land have risen from the sea," Sarker said.

"A rise in sea level will offset this and slow the gains made by new territories, but there will still be an increase in land. We think that in the next 50 years we may get another 1,000 square kilometres of land."

Mahfuzur Rahman, head of Bangladesh Water Development Board's Coastal Study and Survey Department, has also been analysing the buildup of land on the coast.

He told AFP findings by the IPCC and other climate change scientists were too general and did not explore the benefits of land accretion.

"For almost a decade we have heard experts saying Bangladesh will be under water, but so far our data has shown nothing like this," he said.

Posted on July 31, 2008 12:32 AM View this article | Comments (14)
Posted to Author: Pielke Jr., R. | Climate Change | Prediction and Forecasting

July 28, 2008

Draft CCSP Synthesis Report

The U.S. Climate Change Science Program has put online for public comment a draft version of its synthesis report ( here in PDF), and I suppose the good news is that it is a draft, which means that it is subject to revision. But what the draft includes is troubling in several respects.

First, the report adopts an approach to presenting the science more befitting an advocacy group, rather than a interagency science assessment. The report ignores the actual literature on economics and policy, choosing instead to present fluffy exhortations about the urgency of action and reducing emissions. I can get that level of policy discussion from any garden variety NGO, for $2 billion per year over the past 18 years, I would expect a bit more.

The report opens with this language:

The Future is in Our Hands
Human-induced climate change is affecting us now. Its impacts on our economy, security, and quality of life will increase in the decades to come. Beyond the next few decades, when warming is "locked in" to the climate system from human activities to date, the future lies largely in our hands. Will we begin reducing heat-trapping emissions now, thereby reducing future climate disruption and its impacts? Will we alter our planning and development in ways that reduce our vulnerability to the changes that are already on the way? The choices are ours.

Pretty thin stuff. The report speaks of urgency:

Once considered a problem mainly for the future, climate change is now upon us. People are at the heart of this problem: we are causing it, and we are being affected by it. The rapid onset of many aspects of climate change highlights the urgency of confronting this challenge without further delay. The choices that we make now will influence current and future emissions of heat-trapping gases, and can help to reduce future warming.

It is not within the Congressional mandate of the CCSP to tell policymakers when to act or what goals to pursue. The report does have some limited discussion of options, which would be great (and within the mandate) if it were comprehensive and scientifically rigorous. Unfortunately, it is neither.

Despite recognizing that some adaptation will be necessary, and discussing adaptive responses in the text, the report has a strong bias against adaptation in favor of mitigation:

The more we mitigate (reduce emissions), the less climate change we’ll experience and the less severe the impacts will be, and thus, the less adaptation will be required. . . Despite what is widely assumed to be the considerable adaptive capacity of the United States, we have not always succeeded in avoiding significant losses and disruptions, for example, due to extreme weather events. There are many challenges and limits to adaptation. Some adaptations will be very expensive. We will be adapting to a moving target, as future climate will not be stationary but continually changing. And if emissions and thus warming are at the high end of future scenarios, some changes will be so large that adaptation is unlikely to be successful.

A large body of work, some of which I’ve contributed, indicates that adaptation and mitigation are not tradeoffs, but complements. Somehow this literature escaped the thorough review done by the authors of this report.

The report claims to be focused on bringing together the "best available science." However in the area of my expertise, disasters and climate change, the report is an embarrassment. For example, once again, it uses the economic costs of disasters as evidence of climate change and its impacts, as shown in the following figure from the report.

Then, later in the report it discusses increasing U.S. precipitation under the heading "Floods" and next to a picture of a flooded house (below). However, in the U.S. there has been no increase in streamflow and flood damage has decreased dramatically as a fraction of GDP. Thus the report reflects ignorance on this subject or is willfully misleading. Neither prospect gives one much confidence in a government science report.

In short, in areas where I have expertise, at best the reporting of the science of climate impacts in this report is highly selective. Less generously it is misleading, incorrect, and a poor reflection on the government scientists whose names appear on the title page, many of whom I know and have respect for. The report asks for comments during the next few weeks, and I will submit some reactions, which I'll also post here.

So why does the report have such an advocacy focus and rely on misleading arguments?

One answer is to have a look to the people chiefly responsible for the editing of the report, and also the section on natural disasters, where one person's views are reported almost exclusively to any others.

Perhaps it is time to rotate control of U.S. government "science" reports to some new faces?

Posted on July 28, 2008 01:51 PM View this article | Comments (21)
Posted to Author: Pielke Jr., R. | Climate Change | Disasters | Scientific Assessments

Free Enterprise but not Free Speech

The management of the Free Enterprise Action Fund have thrown their hat into the ring seeking to limit what can be said or claimed in the context of climate change. In this case they have asked the U.S. government's Securities and Exchange Commission (SEC) to pass judgment on whether certain claims by companies can be considered false and misleading, and thus in violation of securities laws of the U.S. government.

The fund is run by Steven Milloy (of junkscience.com) and Thomas Borelli, and according to Google Finance the fund seeks to achieve long-term growth "through investments and advocacy that promote the American system of free enterprise." I'm no stockbroker, but it seems like a gussied up market index fund to me. (Isn't any investment in the stock market promoting free enterprise? But I digress . . .) Anyway, here is the full text of their letter to the SEC:

Ms. Florence E. Harmon Acting Secretary U.S. Securities and Exchange Commission 100 F Street, N.E. Washington, D.C. 20549
Re: Petition for Interpretive Guidance on Public Statements Concerning Global Warming and Other Environmental Issues

Dear Ms. Harmon,

We are writing on behalf of the Free Enterprise Action Fund ("FEAOX"), a publicly-traded mutual fund, to petition the U.S. Securities and Exchange Commission ("SEC" or "Commission") to issue interpretive guidance pursuant to the Securities and Exchange Act of 1934 ("the Act") that would warn registrants against making potentially false and misleading statements pertaining to global warming and other environmental issues.

We believe the Commission should take action immediately to protect investors.

I. Examples of potentially false and misleading statements made by registrants.

Below are but a few examples of the sort of potentially false and misleading statements being made by registrants. The problematic nature of these statements is discussed in Section II.

* Exelon Corp. issued a media release and placed full-page advertisements in major newspapers on July 15, 2008 stating, "The science is overwhelming -- climate change is happening now and human activity is the primary cause."

* Lehman Brothers issued a report on climate change featuring the so-called "hockey stick" graph to support the notion that humans are causing global warming.

* The General Electric Company issued a "Call for Action" to "slow, stop and even reverse the damage of greenhouse gasses."

* Toyota Motor Corp. states in a report, "When we drive a vehicle, it consumes fossil fuels and emits CO2, a major contributor to climate change."

* Goldman Sachs states in a 2007 report, "By now, the dynamics of global warming are widely known, and we find no reason to dispute the scientific assumptions."

* Caterpillar said in a public statement that, "We must take action now [to reduce carbon dioxide emissions] or risk serious harm to our planet."

All these statements are potentially false and/or misleading as recent events show.

II. Recent events that put registrants at risk of making false and misleading statements.

A number of recent developments have tended to expose the above-mentioned registrant statements (and probably many others) as false and/or misleading, including:

* The American Physical Society, the leading professional society for American physicists announced in July 2008 on one of its websites that, "There is a considerable presence within the scientific community of people who do not agree with the IPCC conclusion that anthropogenic CO2 emissions are very probably likely to be primarily responsible for the global warming that has occurred since the Industrial Revolution."

* In May 2008, the Oregon Institute of Science and Medicine released a petition signed by more than 31,000 U.S. scientists stating, "There is no convincing scientific evidence that human release of carbon dioxide, methane or other greenhouse gases is causing, or will cause in the future, catastrophic heating of the Earth's atmosphere and disruption of the Earth's climate..."

* India's National Action Plan on Climate Change issued in June 2008 states, "No firm link between the documented [climate] changes described below and warming due to anthropogenic climate change has yet been established." Researchers belonging to the UN Intergovernmental Panel on Climate Change (IPCC) reported in the science journal Nature (May 1) that, after adjusting their climate model to reflect actual sea surface temperatures of the last 50 years, "global surface temperature may not increase over the next decade," since natural climate variation will drive global climate.

* Climate scientists reported in the December issue of the International Journal of Climatology, published by Britain's Royal Meteorological Society, that observed temperature changes measured over the last 30 years don't match well with temperatures predicted by the mathematical climate models relied on by the IPCC.

* A British judge ruled in October 2007 that Al Gore's film, "An Inconvenient Truth," contained so many factual errors that a disclaimer was required to be shown to students before they viewed the film.

* A panel of the National Academy of Sciences concluded in 2006 that the "hockey stick" graph is not proof that human activity is linked to global warming.

III. Conclusion

Based on the foregoing, we request that the Commission immediately inform and remind registrants that:

1. False and/or misleading statements on material matters may violate the anti-fraud provision of the federal securities laws.

2. Statements by registrants on global warming and other environmental issues could be considered material.

3. There is considerable ongoing debate about the science of global warming and its impacts and;

4. Statements to the effect that "the science is conclusive," "the debate is over," and that "human activities are definitely causing harmful global warming" should be avoided.

If you have any questions, please contact the undersigned at 301-258-2852.

Sincerely,

/s/

Steven J. Milloy, MHS, JD, LLM
Thomas J. Borelli, PhD
Managing Partners
Portfolio Managers, Free Enterprise Action Fund

Call me a skeptic -- go ahead, it is OK -- but I don't think this complaint has any chance of succeeding, as the example statements that they have cited are either opinions or puffery. Are these examples really the best that they could come up with?

What is (again) most troubling about this sort of behavior is the recourse to legal methods to limit what can or cannot be claimed about climate change in political debate. And yes, I am viewing the actions of the Free Enterprise Action Fund management as a political act with little relevance to the actual performance of their portfolio of investments. Of course, I see that efforts at moral suasion aren't faring so well so perhaps the thinking -- on both sides of this political debate -- is that if you can't win the debate on the merits, then silencing your opponents via the force of law is the next best thing. A pity, if so.

Posted on July 28, 2008 12:51 AM View this article | Comments (6)
Posted to Author: Pielke Jr., R. | Climate Change | Science + Politics

July 25, 2008

A brief account of an aborted contribution to an ill-conceived debate

A guest post by Dennis Bray and Hans von Storch

The July 2008 newsletter of the American Physical Society (APS) opened a debate concerning the IPCC consensus related to anthropogenic induced climate change. We responded with a brief comment concerning the state and changing state of consensus as indicated by two surveys of climate scientists. Data was presented concerning climate scientists assessments of the understanding of atmospheric physics, climate related processes, climate scientists level of agreement with the IPCC as representative of consensus and of the level of belief in anthropogenic warming. (The full manuscript is available here .) Our comment was summarily dismissed by the editors as polemic, political and unscientific. The following is a brief account of this episode.

The APS Forum on Physics and Society states "The Forum on Physics and Society is a place for discussion and disagreement on scientific and policy matters". The Forum on Physics and Society, Newsletter, July 2008 began a debate "concerning one of the main conclusions" of the IPCC. The intended debate was clearly evident in the statement,

There is a considerable presence within the scientific community of people who do not agree with the IPCC conclusion that anthropogenic CO2 emissions are very probably likely to be primarily responsible for global warming ...

There is no reference as to how this statement was determined or its validity known. It is very probably likely to be primarily ethereal.

The intended debate seemed to be aimed at prompting a discussion, or perhaps as the two papers to date seem to suggest, an evaluation of the methods employed in reaching the IPCC conclusion. Two invited articles were published to set off the debate, one pro and one contra to the IPCC conclusion. Oddly enough, neither paper appears to be authored by a climate scientist per se although both present a detailed discussion of atmospheric physics. Subsequent contributions were invited from the "physics" community for "comments or articles that are scientific in nature."

So here we have two editors (who are themselves not climate scientists) soliciting invited papers from authors who, as far as we know, have never had any peer reviewed publications pertaining to climate science, setting off a debate concerning the consensus in the climate sciences by what appears to be a mere declaration of the current state of the consensus. The editors of the newsletter should be commended however for at least stating that the "correctness or fallacy of that [the IPCC] conclusion has immense implications for public policy."

Our interests were drawn by statements found on the web page: 1. the Forums declaration that it is "a place for discussion and disagreement on scientific and policy matters", and 2. the statement "There is a considerable presence within the scientific community of people who do not agree with the IPCC conclusion that anthropogenic CO2 emissions are very probably likely to be primarily responsible for global warming ...". We have been working for some time in the area of assessing the levels of consensus in the climate science community and therefore decided to submit a brief (and rapidly rejected) comment (PDF.) to the debate.

Our stance concerning "consensus" (on any matter) is:

1. Consensus and certainty are two different concepts, which sometimes are parallel, although often not.

2. Consensus is simply a level of agreement among practitioners and might be subject to change over time.

3. Consensus is a level of agreement in belief of the relevance of the theory to the issue and the casual relationship inherent in the theory

and in particular reference to climate science

4. Climate change science is considered to be multidisciplinary and therefore the knowledge claims comprising the consensus is considered to be multidimensional, that is, not able to be captured in a single statement.

In short, consensus is not as simple as a yes - no response. It is a negotiated outcome of multiple levels of expertise.

Now, returning to our submission, or more precisely, the rejection of our submission, the first rejection arrived in a matter of hours. Short and to the point, it said:

The original invitation was for participation in a scientific debate, not a political one. As your attached piece is not primarily of a scientific nature, we cannot consider it for publication in our newsletter. In my editorial comments for the July 2008 issue, I emphasized that we are not interested in publishing anything of a polemical or political nature.

The "emphasized" points are of interest. The paper was neither polemic nor political, as we invite the readers of the blog to verify, however giving the editors the benefit of the doubt, we asked for clarification. Again the APS response was quite rapid:

Your article [...] is not about technical issues concerning climate research. Instead, it is about the opinions of scientists. I would be glad to consider publication of articles, comments, or letters from you that address specific technical issues connected with climate research.

Now, aren’t the "opinions of scientists" the foundation of consensus? The "opinions of scientists" in our analysis represent not a political statement but a scientific comment. The data is empirical and the paper was deliberately devoid of political or polemic statement. Our paper does definitely not address a specific technical issue but it does provide a collective peer assessment of a number of specific technical issues (such as: representation of hydrodynamics and greenhouse gases). Indeed, our concern was to substantiate quantitatively the loose assertion of an anonymous APS officer:

There is a considerable presence within the scientific community of people who do not agree with the IPCC conclusion that anthropogenic CO2 emissions are very probably likely to be primarily responsible for global warming.

An estimate based on data can be read in our short comment.

Posted on July 25, 2008 06:24 AM View this article | Comments (3)
Posted to Author: Others | Climate Change | Science + Politics | Scientific Assessments

July 18, 2008

Adaptation Policies for Biodiversity: Facilitated Dispersal

Professor Ove Hoegh-Guldberg of Queensland University and colleagues have an important article on “Assisted Colonization and Rapid Climate Change” in this week’s issue of Science (pdf). The author’s argue:

Rapid climatic change has already caused changes to the distributions of many plants and animals, leading to severe range contractions and the extinction of some species (1, 2). The geographic ranges of many species are moving toward the poles or to higher altitudes in response to shifts in the habitats to which these species have adapted over relatively longer periods (1-4). It already appears that some species are unable to disperse or adapt fast enough to keep up with the high rates of climate change (5, 6). These organisms face increased extinction risk, and, as a result, whole ecosystems, such as cloud forests and coral reefs, may cease to function in their current form (7-9).

Current conservation practices may not be enough to avert species losses in the face of mid- to upper-level climate projections (>3°C) (10), because the extensive clearing and destruction of natural habitats by humans disrupts processes that underpin species dispersal and establishment. Therefore, resource managers and policy-makers must contemplate moving species to sites where they do not currently occur or have not been known to occur in recent history. This strategy flies in the face of conventional conservation approaches.

The strategy flies in the face of conventional conservation approaches due to the numerous risks associated with the introduction of invasive species. The authors fully acknowledge these risks.

The world is littered with examples where moving species beyond their current range into natural and agricultural landscapes has had negative impacts. Understandably, notions of deliberately moving species are regarded with suspicion. Our contrary view is that an increased understanding of the habitat requirements and distributions of some species allows us to identify low-risk situations where the benefits of such "assisted colonization'" can be realized and adverse outcomes minimized…

…One of the most serious risks associated with assisted colonization is the potential for creating new pest problems at the target site. Introduced organisms can also carry diseases and parasites or can alter the genetic structure and breeding systems of local populations…

…In addition to the ecological risks, socioeconomic concerns must be considered in decisions to move threatened species. Financial or human safety constraints, for example, may make a species' introduction undesirable. It is likely to be unacceptable to move threatened large carnivores or toxic plants into regions that are important for grazing livestock…

These risks do not invalidate the authors' major point. If we want to conserve current biodiversity in a changing climate, we will likely need creative alternatives to current conservation approaches. Facilitated dispersal of species is one option that deserves consideration in specific conservation contexts. However, it is far from a silver bullet.

Posted on July 18, 2008 08:57 AM View this article | Comments (0)
Posted to Author: Cherney, D. | Biodiversity | Climate Change | Environment

July 14, 2008

Replications of our Normalized Hurricane Damage Work

This post highlights two discussion papers that have successfully replicated our normalized hurricane damage analyses using different approaches and datasets. Interestingly, both papers claim a trend in losses after normalization, but do some only by using a subset of the data – starting in 1950 in the first case and 1971 and the second case. Our dataset shows the same trends when arbitrarily selecting these shorter time frames, however, as we reported, we found no trends in the entire dataset.

If you’d just like the bottom line, here it is:

I am happy to report that Nordhaus (2006) and Schmidt et al. (2008) offer strong confirmatory evidence in support of the analysis that we have presented on adjusting U.S. hurricane losses over time. What do these studies say about the debate over hurricanes and climate change? Well, almost nothing (despite the unsuccessful effort by Schmidt et al. to reach for such a connection). There is no long-term trend in the landfall behavior of U.S. hurricanes, so it is only logical that there would also be no long-term trends in normalized damage as a function of storm behavior. Those looking for insight on this debate will need to look elsewhere. If it is to be found, such a linkage will be found in the geophysical data long before it shows up in the damage data, as we asserted at our Hohenkammer workshop.

Please read on if you are interested in the details.

The first paper is by the leading economist William Nordhaus (2006, PDF). His analysis uses the same original loss data but adjusts it for GDP rather than population, wealth, and housing units. His analysis uses our 1998 study which we updated in 2008. Nordhaus claims to have "verified our analysis" but he does leave a loose end (emphasis added):

Our estimates indicate that the time trend in the damage function is positive. For example, the time trend in the OLS full-sample equation found that normalized damages have risen by 2.9 (+0.76) percent per year, indicating increased vulnerability to storms of a given size.
This is contrary to Roger A. Pielke, Jr., "Are There Trends in Hurricane Destruction?" Nature, Vol. 438, December 2005, E11, who reports no statistically significant trend. Similar negative results were found in Roger A. Pielke, Jr. and Christopher W. Landsea, "La Niña, El Niño, and Atlantic Hurricane Damages in the United States," Bull. Amer. Meteor. Soc., vol. 80, 2027-2033. Additionally, issues of comparability over time are non-trivial, as is discussed in Christopher W. Landsea, "Hurricanes and Global Warming," Nature, Vol. 438, December 2005, E11-E12. The reasons for the difference in findings have not been resolved.

The reason for the difference in findings should be completely obvious: Nordhaus looks at 1950-2005, and Pielke (2005) and Pielke and Landsea (1998) both begin their analysis in 1900. Pielke (2005, PDF) reports:

For example, take the 86 storms causing at least US$1 billion in normalized damages, which removes a bias caused by small storms resulting in no damage in the early twentieth century (that is, not subjected to normalization). There is an average per-storm loss in 1900–50 for 40 storms (0.78 events per year) of $9.3 billion, and an average per-storm loss in 1951–2004 for 46 storms (0.85 events per year) of $7.0 billion; this difference is not statistically significant. Adding Hurricane Katrina to this data set, even at the largest loss figures currently suggested, would not change the interpretation of these results.

The following figures illustrate this point quite clearly. The first figure is from Nordhaus:

The second figure is from the data of Pielke et al. 2008 (PDF):

Clearly, the datasets show the same trends. However, our entire dataset shows no trend, as we reported in the paper:

The two normalized data sets reported here show no trends either in the absolute data or under a logarithmic transformation: the variance explained by a best-fit linear trend line=0.0004 and 0.0003, respectively, for PL05, and 0.0014 and 0.00006, respectively, for CL05. The lack of trend in twentieth century normalized hurricane losses is consistent with what one would expect to find given the lack of trends in hurricane frequency or intensity at landfall. This finding should add some confidence that, at least to a first degree, the normalization approach has successfully adjusted for changing societal conditions. Given the lack of trends in hurricanes themselves, any trend observed in the normalized losses would necessarily reflect some bias in the adjustment process, such as failing to recognize changes in adaptive capacity or misspecifying wealth. That we do not have a resulting bias suggests that any factors not included in the normalization methods do not have a resulting net large significance.

So to summarize, Nordhaus (2006) and Pielke et al. (2008) reconcile perfectly.

A second study is just out by Silvio Schmidt et al. (2008, PDF) which applies a modified version of our normalization methodology to hurricane losses found in the Munich Reinsurance global loss dataset. This study finds no significant trend from 1950, using a log transformation of the dataset:

The trend analysis for the period 1950–2005 yields no statistically significant trend in annual adjusted losses. Even if the two extreme years, 2004 and 2005, are omitted from the trend analysis, no trend can be identified in which the explanatory variable time is significant. Thus, no conclusion can be drawn regarding a possible trend in the periods 1950–2005 and 1950–2003.

The paper does identify a statistically significant trend starting in 1971, but the significance disappears when Katrina is removed from the dataset. Once again, the Schmidt et al. analysis is perfectly consistent with our analysis. The following figure shows their log-transformed data from 1950:

And the following graph is the same transformation applied to the data of Pielke et al. (2008).

One notable difference is that the Munich Re dataset apparently has some gaps, as it reports a number of years with zero damage that our dataset shows the presence of damaging storms. From the graph is should be clear that any claim of a trend over the dataset depends upon 2004 and 2005. And even in this case Schmidt et al. were only able to identify a statistically significant trend by starting with 1971 (which they claim as the start of a cold phase, contrary to most studies that use 1970). The following figure from Schmidt et al. shows how close the two analyses actually are (the red curve is Pielke et al. 2008):

The differences between the two analyses are very small, and I would guess, of no particular statistical significance over the time series of the dataset.

So I am happy to report that Nordhaus (2006) and Schmidt et al. (2008) offer strong confirmatory evidence in support of the analysis that we have presented on adjusting U.S. hurricane losses over time.

What do these studies say about the debate over hurricanes and climate change? Well, almost nothing despite efforts by Schmidt et al. to reach for such a connection. There is no long-term trend in the landfall behavior of U.S. hurricanes, so it is only logical that there would also be no long-term trends in normalized damage as a function of storm behavior. Those looking for insight on this debate will need to look elsewhere. If it is to be found, such a linkage will be found in the geophysical data long before it shows up in the damage data, as we asserted at our Hohenkammer workshop.

Posted on July 14, 2008 07:35 AM View this article | Comments (2)
Posted to Author: Pielke Jr., R. | Climate Change | Disasters | Risk & Uncertainty

July 09, 2008

Climate Science and National Interests

The Indian government has put out a climate change action plan (PDF) that places economic development and adaptation ahead of mitigation (sound familiar?). The report was endorsed by IPCC chairman Rajendra Pachauri:

[Pachauri] said that India has realised the climate change threat. India's climate change action plan recently released by Prime Minister Manmohan Singh is a "good policy document" and needs to be implemented.

Interesting, the report's views of climate science are at odds with that presented by the IPCC.

The Indian climate change action plan states of observed climate changes in India (p. 15):

No firm link between the documented [climate] changes described below and warming due to anthropogenic climate change has yet been established.

For example, the Indian report states of the melting of Himalayan glaciers (p. 15):

The available monitoring data on Himalayan glaciers indicates while some recession of glaciers has occurred in some Himalayan regions in recent years, the trend is not consistent across the entire mountain chain. It is accordingly, too early to establish long-term trends or their causation, in respect of which there are several hypotheses.

By contrast, the IPCC (WG II Ch. 10 p. 493)says of Himalayan glacier melt:

The receding and thinning of Himalayan glaciers can be attributed primarily to the global warming due to increase in anthropogenic emission of greenhouse gases.

Imagine the reaction if the U.S. (or British or German or Australian . . .) government put out a report placing economic growth ahead of mitigation while contradicting the science of the IPCC. Dr. Pachauri's endorsement of a report that contradicts the IPCC indicates that issues of science and national interests are apparently universal.

Posted on July 9, 2008 06:50 PM View this article | Comments (3)
Posted to Author: Pielke Jr., R. | Climate Change | International | Science + Politics

Governance as Usual: Film at 11

I have long considered Andy Revkin of the New York Times to be the dean of reporters covering climate science. But there is one issue that I think he consistently gets wrong, and that is his coverage of the politics of internal bureaucratic-politician conflicts. His story in today's NYT is a good example.

Andy writes, breathlessly:

Vice President Dick Cheney’s office was involved in removing statements on health risks posed by global warming from a draft of a health official’s Senate testimony last year, a former senior government environmental official said on Tuesday.

Watergate this is not. In fact, the editing of testimony probably occurs just about every time that an employee of the executive branch is set to testify before Congress, and this has been standard operating procedure for decades. The more significant the issue the higher up the chain of command the review takes place. The procedure is clearly outlined in OMB Circular-21 (PDF):

Unless a specific exemption is approved by OMB, materials subject to OMB clearance include:
• All budget justifications and budget-related oversight materials;
• Testimony before and letters to congressional committees;
• Written responses to congressional inquiries or other materials for the record; . . .

Now if you or I were in a decision making position in the Executive Branch we might make decisions about what to allow in testimony differently than those in the current administration. But make no mistake, such decisions are under the discretion of the administration. Federal employees who don't like those decisions are free to go public or even resign (both occurred in this case).

A spat between elected and career officials may or may not be significant, as they happen all the time. My problem with the track record of coverage of such disputes on climate change by the NYT is that it they have been very misleading about what the news is in such situations. The headline reads: "Cheney’s Office Said to Edit Draft Testimony" suggesting that there is something improper or perhaps even illegal about the editing of testimony in the Executive Office of the President. There is not.

Revkin and I have disagreed on this same issue before. At the time I called the NYT coverage of Bush officials editing Bush Administration documents a "manufactured controversy" and I think that statement applies to today's revelations as well.

Here are the comments I left on Andy's blog, to which, perhaps understandably, he reacted a bit snippily:

Andy-
This is a "dog bites man" story in the form of "pit bull bites man". It is red meat for those who do not like pit bulls, but at the same time, everyone knows that pit bulls bite.

Can you name a presidential administration in which senior officials did not play a role in shaping testimony on important issues? This is a loaded question, because of course you cannot.

I’m no fan of Bush or Cheney, or their approach to climate, but at the same time I think that it is only appropriate to present to your readers an accurate sense of how policy making actually works. In this case, Marburger’s explanation [cited on Andy's blog] is exactly correct.

It is perfectly fair for people to disagree with the actions taken by the Bush Administration on this testimony, but was it improper or even illegal? No, not even close.

Science does not dictate particular policies, and presidential administration’s have wide latitude in what information they present and how they present it. This is spelled out in OMB Circular 22:

http://www.whitehouse.gov/omb/circulars/a11/current_yea r/s22.pdf

Dog bites man is not news.

[ANDY REVKIN says: Roger, maybe you forgot to read the entire 2004 story, which made the points you’re making now.]

— Posted by Roger Pielke, Jr.

Posted on July 9, 2008 01:44 PM View this article | Comments (6)
Posted to Author: Pielke Jr., R. | Climate Change | Journalism, Science & Environment | Science + Politics

The IPCC, Scientific Advice and Advocacy

For some time the leadership of the IPCC have sought to use the institution's authority to promote a specific political agenda in the climate debate. The comments made yesterday by Rajendra Pachauri, head of the IPCC, place the organization in opposition to the G8 leaders position on climate change:

RK Pachauri, head of the Intergovernmental Panel on Climate Change (IPCC), on Tuesday slammed developed countries for asking India and China to cut greenhouse gas emissions while they themselves had not taken strong steps to cut down pollution.
"India can not be held for any emission control. They (developed countries) should get off the back of India and China," Pachauri told reporters here.

"We are an expanding economy. How can we levy a cap when millions are living with deprivation? To impose any cap (on India) at a time when others (industrialised countries) are saying that they will reach the 1990 level of emission by 2025 is hazardous," Pachauri said.

He said countries like the US and Canada should accept their responsibilities and show leadership in reducing green house gases like carbon dioxide and methane.

Pachauri said millions of Indian do not have access to electricity and their per capita income is much less. At this point, you cannot ask a country to "stop developing".

Who does Dr. Pachauri speak for as head of the "policy neutral" IPCC?

It is as if the head of the CIA (or any other intelligence agency) decided to publicly criticize the government of Iran (or other country). Such behavior would seriously call into question the ability of the intelligence agency to perform its duties, which depend upon an ability to leave advocacy to other agencies. The United States has a Department of State responsible for international relations. The CIA collects intelligence in support of decision makers. These agencies have different roles in the policy process -- hoenst broker and issue advocate.

The IPCC seems to want to both gather intelligence and decide what to do based on that intelligence. This is not a recipe for effective expert advice. Leaders in many areas would not stand for this conflation of advice and advocacy, so why does it continue to occur in the climate arena with little comment?

June 20, 2008

What the CCSP Extremes Report Really Says

Yesterday the U.S. Climate Change Science Program released an assessment report titled "Weather and Climate Extremes in a Changing Climate" (PDF) with a focus on the United States. This post discusses some interesting aspects of this report, with an emphasis on what it does not show and does not say. It does not show a clear picture of ever increasing extreme events in the United States. And it does not clearly say why damage has been steadily increasing.

First, let me emphasize that the focus of the report is on changes in extremes in the United States, and not on climate changes more generally. Second, my comments below refer to the report’s discussion of observed trends. I do not discuss predictions of the future, which the report also covers. Third, the report relies a great deal on research that I have been involved in and obviously know quite well. Finally, let me emphasize that anthropogenic climate change is real, and deserving of significant attention to both adaptation and mitigation.

The report contains several remarkable conclusions, that somehow did not seem to make it into the official press release.

1. Over the long-term U.S. hurricane landfalls have been declining.

Yes, you read that correctly. From the appendix (p. 132, emphases added):

The final example is a time series of U.S. landfalling hurricanes for 1851-2006 . . . A linear trend was fitted to the full series and also for the following subseries: 1861-2006, 1871-2006, and so on up to 1921-2006. As in preceding examples, the model fitted was ARMA (p,q) with linear trend, with p and q identified by AIC.
For 1871-2006, the optimal model was AR(4), for which the slope was -.00229, standard error .00089, significant at p=.01. For 1881-2006, the optimal model was AR(4), for which the slope was -.00212, standard error .00100, significant at p=.03. For all other cases, the estimated trend was negative, but not statistically significant.

2. Nationwide there have been no long-term increases in drought.

Yes, you read that correctly. From p. 5:

Averaged over the continental U.S. and southern Canada the most severe droughts occurred in the 1930s and there is no indication of an overall trend in the observational record . . .

3. Despite increases in some measures of precipitation (pp. 46-50, pp. 130-131), there have not been corresponding increases in peak streamflows (high flows above 90th percentile).

From p. 53 (emphasis added):

Lins and Slack (1999, 2005) reported no significant changes in high flow above the 90th percentile. On the other hand, Groisman et al. (2001) showed that for the same gauges, period, and territory, there were statistically significant regional average increases in the uppermost fractions of total streamflow. However, these trends became statistically insignificant after Groisman et al. (2004) updated the analysis to include the years 2000 through 2003, all of which happened to be dry years over most of the eastern United States.

4. There have been no observed changes in the occurrence of tornadoes or thunderstorms

From p. 77:

There is no evidence for a change in the severity of tornadoes and severe thunderstorms, and the large changes in the overall number of reports make it impossible to detect if meteorological changes have occurred.

5. There have been no long-term increases in strong East Coast winter storms (ECWS), called Nor’easters.

From p. 68:

They found a general tendency toward weaker systems over the past few decades, based on a marginally significant (at the p=0.1 level) increase in average storm minimum pressure (not shown). However, their analysis found no statistically significant trends in ECWS frequency for all nor’easters identified in their analysis, specifically for those storms that occurred over the northern portion of the domain (>35°N), or those that traversed full coast (Figure 2.22b, c) during the 46-year period of record used in this study.

6. There are no long-term trends in either heat waves or cold spells, though there are trends within shorter time periods in the overall record.

From p. 39:

Analysis of multi-day very extreme heat and cold episodes in the United States were updated from Kunkel et al. (1999a) for the period 1895-2005. The most notable feature of the pattern of the annual number of extreme heat waves (Figure 2.3a) through time is the high frequency in the 1930s compared to the rest of the years in the 1895-2005 period. This was followed by a decrease to a minimum in the 1960s and 1970s and then an increasing trend since then. There is no trend over the entire period, but a highly statistically significant upward trend since 1960. . . Cold waves show a decline in the first half of the 20th century, then a large spike of events during the mid-1980s, then a decline. The last 10 years have seen a lower number of severe cold waves in the United States than in any other 10-year period since record-keeping began in 1895 . . .

From the excerpts above it should be obvious that there is not a pattern of unprecedented weather extremes in recent years or a long-term secular trend in extreme storms or streamflow. Yet the report shows data in at least three places showing that the damage associated with weather extremes has increased dramatically over the long-term. Here is what the report says on p. 12:

. . . the costs of weather-related disasters in the U.S. have been increasing since 1960, as shown in Figure 1.2. For the world as a whole, "weather-related [insured] losses in recent years have been trending upward much faster than population, inflation, or insurance penetration, and faster than non-weather-related events" (Mills, 2005a). Numerous studies indicate that both the climate and the socioeconomic vulnerability to weather and climate extremes are changing (Brooks and Doswell, 2001; Pielke et al., 2008; Downton et al., 2005), although these factors’ relative contributions to observed increases in disaster costs are subject to debate.

What debate? The report offers not a single reference to justify that there is a debate on this subject. In fact, a major international conference that I helped organize along with Peter Hoeppe of Munich Re came to a consensus position among experts as varied as Indur Goklany and Paul Epstein. Further, I have seen no studies that counter the research I have been involved in on trends in hurricane and flood damage in relation to climate and societal change. Not one. That probably explains the lack of citations.

They reference Mills 2005a, but fail to acknowledge my comment published in Science on Mills 2005a (found here in PDF) and yet are able to fit in a reference to Mills 2005b, titled "Response to Pielke" (responding to my comment). How selective. I critiqued Mills 2005a on this blog when it came out, writing some strong things: "shoddy science, bad peer review and a failure of the science community to demand high standards is not the best recipe for helping science to contribute effectively to policy."

The CCSP report continues:

For example, it is not easy to quantify the extent to which increases in coastal building damage is due to increasing wealth and population growth in vulnerable locations versus an increase in storm intensity. Some authors (e.g., Pielke et al., 2008) divide damage costs by a wealth factor in order to "normalize" the damage costs. However, other factors such as changes in building codes, emergency response, warning systems, etc. also need to be taken into account.

This is an odd editorial evaluation and dismissal of our work (Based on what? Again not a single citation to literature.) In fact, the study that I was lead author on that is referenced (PDF) shows quantitatively that our normalized damage record matches up with the trend in landfall behavior of storms, providing clear evidence that we have indeed appropriately adjusted for the effects of societal change in the historical record of damages.

The CCSP report then offers this interesting claim, again with the apparent intention of dismissing our work:

At this time, there is no universally accepted approach to normalizing damage costs (Guha-Sapir et al., 2004).

The reference used to support this claim can be found here in PDF. Perhaps surprisingly, given how it is used, Guha-Sapir et al. contains absolutely no discussion of normalization methodologies, but instead, a general discussion of damage estimation. It is therefore improperly cited in support of this claim. However, Guha-Sapir et al. 2004 does say the following on p. 53:

Are natural hazards increasing? Probably not significantly. But the number of people vulnerable and affected by disasters is definitely on the increase.

Sound familiar?

In closing, the CCSP report is notable because of what it does not show and what it does not say. It does not show a clear picture of ever increasing extreme events in the United States. And it does not clearly say why damage has been steadily increasing.

Overall, this is not a good showing by the CCSP.

Posted on June 20, 2008 01:28 AM View this article | Comments (7)
Posted to Author: Pielke Jr., R. | Climate Change | Disasters | Scientific Assessments

June 18, 2008

Op-Ed in Financial Post

UPDATE: At Dot Earth Andy Revkin labels an excerpt from this op-ed the "quote of the day."

I have an invited op-ed in today's Financial Post (a Canadian newspaper with a skeptical editorial perspective on climate change). I argue that even though many scientists oversell the predictive capabilities of climate models, action on climate change still makes sense. Here is an excerpt:

So in the debate on what to do about climate change, what are we to make of the overstated claims of predictive accuracy offered by many scientists? Not surprisingly, the reason for overstated claims lies in the bitter and contested politics of climate change. Myanna Lahsen, an anthropologist who has studied climate modelers, finds that many of these scientists are acutely aware of the fact that any expressed “caveats, qualifications and other acknowledgements of model limitations can become fodder for the anti-environmental movement.” She documents how, more than a decade ago, a prominent climate scientist warned a group of his colleagues at the National Center for Atmospheric Research, home of one of the main U.S. climate modeling efforts that informs the IPCC, to “Choose carefully your adjectives to describe the models. Confidence or lack of confidence in the models is the deciding factor in whether or not there will be policy response on behalf of climate change.”
I witnessed this dynamic in practice while I was waiting to testify on climate policy before the U.S. Congress in 2006. A prominent climate scientist testifying on the panel appearing before mine was asked by a member of Congress about uncertainties in predictions from climate models. The scientist replied, enthusiastically and accurately, that there are a range of important uncertainties coming from scenario inputs and choices in parameterization schemes, instantly overwhelming his congressional audience with technical detail. Much later, and after a long break, the scientist requested an opportunity to clarify his earlier comments, and this time he said, “I would like to give you a little more direct answer to the question on reliability of climate models. I think they are reliable enough to be a very useful guide into the future.”

Lost in the Manichean debate over climate change is the real significance of what climate models really are telling us: We should act on climate mitigation and adaptation not because we are able to predict the future, but because we cannot.

See it all here. Comments and reactions welcomed.

Posted on June 18, 2008 02:04 AM View this article | Comments (22)
Posted to Author: Pielke Jr., R. | Climate Change | Prediction and Forecasting | Science + Politics

June 16, 2008

U.S. Flood Damage 1929-2003

The ongoing Midwest floods are a horrible disaster. The United States however has seen a long-term trend of decreasing flood losses as a fraction of GDP, as shown in the following graph.

Flood Damage 1929-2003.jpg

Sources

Flood damage data: Here (Note no data 1980-82)

GDP data: Here

For further reading:

Pielke, Jr., R.A., M. Downton, J. Z. B. Miller, S. A. Changnon, K. E. Kunkel, and K. Andsager, 2000: Understanding Damaging Floods in Iowa: Climate and Societal Interactions in the Skunk and Raccoon River Basins, Environmental and Societal Impacts Group, National Center for Atmospheric Research, Boulder, CO, August. (PDF)

Pielke, Jr., R. A. and M.W. Downton, 2000. Precipitation and Damaging Floods: Trends in the United States, 1932-97. Journal of Climate, 13(20), 3625-3637. (PDF)

Downton, M. and R. A. Pielke, Jr., 2005. How Accurate are Disaster Loss Data? The Case of U.S. Flood Damage, Natural Hazards, Vol. 35, No. 2, pp. 211-228. (PDF)

Posted on June 16, 2008 03:33 PM View this article | Comments (5)
Posted to Author: Pielke Jr., R. | Climate Change | Disasters

The New Global Growth Path

A very important new paper is forthcoming in the journal Climatic Change which has been published first online. The paper is:

P. Sheehan, 2008. The new global growth path: implications for climate change analysis and policy, Climatic Change (in press).

The paper argues that:

In recent years the world has moved to a new path of rapid global growth, largely driven by the developing countries, which is energy intensive and heavily reliant on the use of coal—global coal use will rise by nearly 60% over the decade to 2010. It is likely that, without changes to the policies in place in 2006, global CO2 emissions from fuel combustion would nearly double their 2000 level by 2020 and would continue to rise beyond 2030. Neither the SRES marker scenarios nor the reference cases assembled in recent studies using integrated assessment models capture this abrupt shift to rapid growth based on fossil fuels, centred in key Asian countries.

This conclusion strongly supports the analysis that we presented in Nature (PDF)not long ago, in which we argued that the mitigation challenge was potentially underestimated in the so-called IPCC SRES (and pre- and post- SRES) scenarios due to overly aggressive assumptions about future trends in the decarbonization of the global economy. Such overly optimistic assumptions are endemic in the literature, found in the Stern Review, and IEA and CCSP assessments, among others.

Sheehan comes to similar conclusions:

To the extent that NGP is a reasonable projection of global trends on current policies out to 2030, it follows that all of the SRES marker scenarios seriously understate unchanged policy emissions over that time, and do so because they do not capture the extent of the expansion in energy use and emissions that is currently taking place in Asia. Nor, as a consequence, do they capture the rapid growth in coal use that is also occurring. . .
The SRES scenarios were a substantial intellectual achievement, and have stood the test of time for almost a decade. But the central feature of global economic trends in the early decades of the twenty-first century—the new growth path shaped by the sustained emergence of China and India, in the context of an open, knowledge-based world economy—could not be foreseen in the 1990s, and is not covered by these scenarios. Many of the SRES scenarios are no longer individually plausible, and as a whole the marker scenarios can no longer be said to ‘describe the most important uncertainties’. As a result, and especially given the emissions intensity of the new growth path, there is an urgent need for new approaches.

Unfortunately, a major obstacle to discussing (much less achieving) new approaches are the very public intellectual and political commitments that have been advanced, based on the earlier assumptions. Unwinding these commitments -- as we have seen -- will take some doing.

PS. See also the NYTs Andy Revkin and Elisabeth Rosenthal on China's growing emissions here. As yet, the dots remain to be connected between such trends unfolding before our eyes and their incongruity with assumptions in energy policy assessments. But reality and policy assessments can diverge only for so long.

Posted on June 16, 2008 03:59 AM View this article | Comments (13)
Posted to Author: Pielke Jr., R. | Climate Change | Energy Policy | Technology Policy

June 12, 2008

Why Costly Carbon is a House of Cards

How can the world achieve economic growth while at the same time decarbonizing the global economy?

This question is important because there is apt to be little public or political support for mitigation policies that increase the costs of energy in ways that are felt in reduced growth. Consider this description of reactions around the world to the recent increasing costs of fuel:

Concerns were growing last night over a summer of coordinated European fuel protests after tens of thousands of Spanish truckers blocked roads and the French border, sparking similar action in Portugal and France, while unions across Europe prepared fresh action over the rising price of petrol and diesel. . .
Protests at rising fuel prices are not confined to Europe. A succession of developing countries have provoked public outcry by ordering fuel price increases. Yesterday Indian police forcibly dispersed hundreds of protesters in Kashmir who were angry at a 10% rise introduced last week. Protests appeared likely to spread to neighbouring Nepal after its government yesterday announced a 25% rise in fuel prices. Truckers in South Korea have vowed strike action over the high cost of diesel. Taiwan, Sri Lanka and Indonesia have all raised pump prices. Malaysia's decision last week to increase prices generated such public fury that the government moved yesterday to trim ministers' allowances to appease the public.

Advocates for a response to climate change based on increasing the costs of carbon-based energy skate around the fact that people react very negatively to higher prices by promising that action won’t really cost that much. For instance, our frequent debating partner Joe Romm says of a recent IEA report (emphasis added):

. . . cutting global emissions in half by 2050 is not costly. In fact, the total shift in investment needed to stabilize at 450 ppm is only about 1.1% of GDP per year, and that is not a "cost" or hit to GDP, because much of that investment goes towards saving expensive fuel.

And Joe tells us that even these "not costly" costs are "overestimated."

If action on climate change is indeed "not costly" then it would logically follow the only reasons for anyone to question a strategy based on increasing the costs of energy are complete ignorance and/or a crass willingness to destroy the planet for private gain. Indeed, accusations of "denial" and "delay" are now staples of any debate over climate policy.

There is another view. Specifically that the current ranges of actions at the forefront of the climate debate focused on putting a price on carbon in order to motivate action are misguided and cannot succeed. This argument goes as follows: In order for action to occur costs must be significant enough to change incentives and thus behavior. Without the sugarcoating, pricing carbon (whether via cap-and-trade or a direct tax) is designed to be costly. In this basic principle lies the seed of failure. Policy makers will do (and have done) everything they can to avoid imposing higher costs of energy on their constituents via dodgy offsets, overly generous allowances, safety valves, hot air, and whatever other gimmick they can come up with.

Analysts and advocates allow this house of cards to stand when trying to sell higher costs of energy to a skeptical public they provide analyses that support a conclusion that acting to cut future emissions is "not costly."

The argument of "not costly" based on under-estimating the future growth of emissions so that the resulting challenge does not appear so large. We have discussed such scenarios on many occasions here and explored their implications in a commentary in Nature (PDF).

One widely-know example is the stabilization wedge analysis of Stephen Pacala and Robert Socolow (PDF. The stabilization wedge analysis concluded that the challenge of stabilizing emissions was no so challenging.

Humanity already possesses the fundamental scientific, technical, and industrial know-how to solve the carbon and climate problem for the next half-century. A portfolio of technologies now exists to meet the world’s energy needs over the next 50years and limit atmospheric CO2 to a trajectory that avoids a doubling of the preindustrial concentration. . . But it is important not to become beguiled by the possibility of revolutionary technology. Humanity can solve the carbon and climate problem in the first half of this century simply by scaling up what we already know how to do.

In a recent interview the lead author of that paper, Pacala provided a candid and eye-opening explanation of the reason why they wrote the paper (emphases added):

The purpose of the stabilization wedges paper was narrow and simple – we wanted to stop the Bush administration from what we saw as a strategy to stall action on global warming by claiming that we lacked the technology to tackle it. The Secretary of Energy at the time used to give a speech saying that we needed a discovery as fundamental as the discovery of electricity by Faraday in the 19th century.
We also wanted to stop the group of scientists that were writing what I thought were grant proposals masquerading as energy assessments. There was one famous paper published in Science [Hoffert et al. 2002] that went down the list [of available technologies] fighting them one by one but never asked "what if we put them all together?" It was an analysis whose purpose was to show we lacked the technology, with a call at the end for blue sky research.

I saw it as an unhealthy collusion between the scientific community who believed that there was a serious problem and a political movement that didn’t. I wanted that to stop and the paper for me was surprisingly effective at doing that. I’m really happy with how it came out – I wouldn’t change a thing.

That doesn’t mean that there aren’t things wrong with it and that history won’t prove it false. It would be astonishing if it weren’t false in many ways, but what we said was accurate at the time.

So lets take a second to reflect on what you just read. Pacala is claiming that he wrote a paper to serve a political purpose and he admits that history may very well prove its analysis to be “false.” But he judges the paper was successful not because of its analytical soundness, but because it served its political function by severing relationship between a certain group of scientific experts and decision makers whose views he opposed.

Why is this problematic? NYU’s Marty Hoffert has explained that the Pacala and Socolow paper was simply based on flawed assumptions. Repeating different analyses with similar assumptions doesn’t make the resulting conclusions any more correct. Hoffert says (emphases added):

The problem with the formulation of Pacala and Socolow in their Science paper, and the later paper by Socolow in Scientific American issue that you cite, is that they both indicate that seven "wedges" of carbon emission reducing energy technology (or behavior) -- each of which creates a growing decline in carbon emissions relative to a baseline scenario equal to 25 billion tonnes less carbon over fifty years -- is enough to hold emissions constant over that period. . . .
A table is presented in the wedge papers of 15 "existing technology" wedges, leading virtually all readers to conclude the carbon and climate problem is soluble with near-term technology; and so, by implication, a major ramp-up of research and development investments in alternate energy technology like the "Apollo-like" R&D Program that we call for, is unnecessary. . . .

The actual number of wedges to hold carbon dioxide below 450 ppm is about 18, not 7, for Pacala-Socolow scenario assumptions, as Rob well knows; in which case we're much further from having the technology we need. The problem is actually much worse than that, since the number of emission-reducing wedges needed to avoid greater than two degree Celsius warming explodes after the mid-century mark if world GDP continues to grow three percent per year under a business-as-usual scenario.

The figure below is from a follow-on paper by Socolow in 2006 (PDF) and clearly indicates the need for 11 additional wedges of emissions reductions from 2005 to 2055. These are called "virtual wedges" which is ironic, because their existence is very real and in fact necessary for the stabilization of emissions to actually occur. (Cutting emissions by half would require another 4 wedges, or 22 total).

If Pacala and Socolow admit that we need 18 wedges to stabilize emissions, and 22 wedges to cut them by half, and this is based on an rosy assumption of only 1.5% growth in emissions to 2055, then why would anyone believe that we need less? If it is conceivable that emissions might grow faster than 1.5% per year, then we will need even more than the 22 wedges. Perhaps much more. But analysts seeking to impose a price on carbon won't tell you this. Instead, some will resort to demagoguery, and others will simply repeat over and over again the consequences of assuming rosy scenarios. None of this will make the mitigation challenge any easier. But as Pacala says in the excerpt above, such strategies may keep more sound analyses out of the debate.

Policies based on the argument that putting a price on carbon will be "not costly' are a house of cards, and based on a range of assumptions that could easily be judged very optimistic. Looking around, what you will see is that the minute that energy prices rise high enough to be felt by the public, action will indeed occur, but it will not be the action that is desired by the climate intelligencia. It will be demands for lower priced energy. And policy makers will listen to these demands and respond. Climate policy analysts should listen as well, because there will be no tricking of the public with rosy scenarios built on optimistic assumptions.

Virtual Triangle.png

June 10, 2008

Who Do National Science Academies Speak For?

UPDATED!

Today the national science academies of the G8+5 issued a statement on climate change (PDF) advocating a greater pace of action on adaptation and mitigation in response to climate change. We have discussed advocacy by science academies here on various occasions, and in this post I'd like to highlight two issues endorsed by the Academies that are still being debated among scientists and advocates, and ask, who do the academies speak for?

1. Clean coal. Carbon capture and storage is a contested technology, for example, by various environmental groups. However, the national science academies endorse its development and use.

Technologies should be developed and deployed for carbon capture, storage and sequestration (CCS), particularly for emissions from coal which will continue to be a primary energy source for the next 50 years for power and other industrial processes. G8+5 economies can take the lead globally to further develop CCS technologies. This will involve governments and industry working collaboratively to develop the financial and regulatory conditions needed to move CCS forward and international coordination in the development of demonstration plants.

2. Geoengineering research. Similarly, geoengineering research (as a separate issue from actual geoengineering) is a contested issue, for instance the recent Conference of Parties to the UN Convention on Biodiversity proposed a moratorium (receiving broad international support) on certain geoengineering experiments.. The national science academies endorse geoengineering without such reservations.

There is also an opportunity to promote research on approaches which may contribute towards maintaining a stable climate (including so-called geoengineering technologies and reforestation), which would complement our greenhouse gas reduction strategies.

Separate from the merit of the policy recommendations advanced by the academies (and for the record I support both CCS and geoengineering research) is the question of who the national science academies speak for and the basis for their endorsement of particular actions.

Do they represent the scientific community within their countries? Their members? Their executive bodies and leadership?

What of public concerns and those among members of the scientific community about CCS and geoengineering?

If the science academies claim to represent a special interest, then whose interest? If they claim to represent common interests, then on what basis is their advocacy to be viewed as legitimate (e.g., is democratic, consensual, authoritative, elite, etc.)?

Posted on June 10, 2008 01:41 PM View this article | Comments (9)
Posted to Author: Pielke Jr., R. | Climate Change | Science + Politics | The Honest Broker

June 09, 2008

An Order of Magnitude in Cost Estimates: Automatic Decarbonization in the IEA Baseline

Last week I mentioned the conclusions of the IEA Energy Technologies Perspectives report. I have had a chance to look at the full report in some depth, with an eye to the assumptions in the report for the spontaneous decarbonization of the global economy.

All assessments of the costs of stabilizing concentrations of carbon dioxide start with a baseline trajectory of future emissions. The costs of mitigation are calculated with respect to reductions from this baseline. In the Pielke, Wigley, and Green commentary in Nature (PDF) we argued that such baselines typically assume very large, spontaneous decreases in energy intensity (energy per unit GDP). The effect of these assumptions is to decrease the trajectory of the baseline, making the challenge of mitigation much smaller than it would be with assumptions of smaller decreases in energy intensity (and a higher baseline trajectory). Obviously, the smaller the gap between the baseline scenario and the mitigation scenario, the smaller the projected costs of mitigation.

The annotated figure below is from the IEA ETP report (Figure 2.8, p. 74), and shows the assumptions of decreasing energy intensity in the baseline scenario (BASELINE), as well as the two mitigation scenarios (ACT [emissions stabilized at current values] and BLUE [emissions half current values]).

IEA Decarb.jpg

In the annotation I show with the red call out the difference between the BASELINE and BLUE scenarios, which the report identifies with a cost of $45 trillion. The magnitude of this difference is about 0.8% per year. However, the report assumes that about twice this rate of decarbonization of the global economy will happen spontaneously (i.e., the magnitude of the BASELINE reductions in energy intensity). With the green call out I ask how the baseline is actually to be achieved.

In numbers, the BLUE scenario assumes that by 2050 a trajectory consistent with stabilization at 450 ppm carbon dioxide will require reductions in emissions from 62 Gt carbon dioxide to 14 Gt. But what if we use a "frozen technology" baseline as recommended in PWG?

Using the assumptions from Annex B of the report for global economic growth (4.2% to 2015, 3.3% 2015-2030, and 2.6% 2030 to 2050 -- we could play with these assumptions as well) results in a frozen technology baseline of 115 Gt carbon dioxide. Thus, 53Gt of carbon dioxide are assumed in the BASELINE to be reduced by the automatic decarbonization of the global economy. This spontaneous decarbonization will occur without any of the technologies proposed in the report to get from the baseline to the mitigation level (otherwise the report would be double-counting the effects of these technologies). What these technologies are is anyone's guess, as the report does not describe them.

If the world does not automatically decarbonize as projected in the IEA baseline, then the costs of mitigation will be considerably higher. By how much?

If we take the report's marginal cost estimate of $200 to $500 per ton for mitigating carbon dioxide, then a simple estimate of the full costs from a frozen technology baseline would be an additional $210 to $530 trillion above the $45 trillion cited in the report. Yes, you read that right.

What if the assumption of automatic decarbonization was off by only 10%? Then the additional cost would be an additional $21 to $53 billion, or about the same magnitude of the IEA's total cost estimate of mitigation (i.e., of moving from the BASELINE to the BLUE trajectory) .

What does this exercise tell us about costs estimates of mitigation?

1. They are highly sensitive to assumptions.

2. Depending on assumptions, cost estimates could vary by more than an order of magnitude.

3. We won't know the actual costs of mitigation until action is taken and costs are observed. Arguments about assumptions are unresolvable.

Meantime, it will be easy to cherrypick a cost for mitigation -- low or high -- that suits the argument that you'd like to make.

Anyone telling you that they have certainty about the future costs of mitigation -- whether that certainty is about high costs or low costs -- is not reflecting the actual uncertainty. Action on mitigation will have to take place before such certainty is achieved, and modified based on what we learn.

Posted on June 9, 2008 02:07 AM View this article | Comments (12)
Posted to Author: Pielke Jr., R. | Climate Change | Energy Policy | Technology Policy

June 06, 2008

IEA on Reducing The Trajectory of Global Emissions

The International Energy Administration released its Energy Technology Perspectives report today, with a view on the prospects of returning global emissions to present values by 2050 and also more aggressively cutting them by half in 2050.

The report has several interesting conclusions:

1. Its cost estimates for stabilizing emissions at current amounts have doubled over the past 2 years to $50 per ton of carbon dioxide.

2. Its estimates for halving emissions from today's levels are $200 to $500 per ton of carbon dioxide.

By contrast, the Stern Review's 2006 estimate of the average cost of a similar reduction in emissions to 2050 was $25 per ton of carbon dioxide (see Figure 9.5 here in PDF), with an uncertainty range that topped out at about $100 per ton. The IPCC AR4 scenarios led to costs ranging up to $200 per ton of carbon dioxide (consistent with a 550 ppm stabilization trajectory by 2050, as seen in figure TS.9 in this PDF). (Note: I am unclear as to how the report handles the baseline issue that we raised in our recent Nature paper, but if they handled it properly, the differences in cost estimates from Stern/IPCC may simply reflect a more transparent accounting.)

What to take from this? Estimates of the economic costs of mitigation are highly unstable and speculative. Consider that the Stern Review considered no costs of oil above $80/barrel. However, the trend in cost estimates is up, due to the higher costs of energy and infrastructure. Efforts to map out the costs of mitigation to 2050 (or 2030 for that matter) are little more than guesses, leaving plenty of room to find a pleasing result.

3. The IEA report sees no path to stabilizing or halving emissions without a massive investment in both nuclear power and carbon capture and storage (for coal and gas). These are both politically controversial and will generate resistance among some groups, perhaps limiting their future prospects. To the extent that this happens other avenues for emissions reductions will need to be found to meet these ambitious goals.

4. Here is what the IEA sees as necessary each year:

The average year-by-year investments between 2010 and 2050 needed to achieve a virtual decarbonisation of the power sector include, amongst others, 55 fossil-fuelled power plants with CCS, 32 nuclear plants, 17,500 large wind turbines, and 215 million square metres of solar panels. [Reducing 2050 emissions to half of today's] also requires widespread adoption of near-zero emission buildings and, on one set of assumptions, [by 2050] deployment of nearly a billion electric or hydrogen fuel cell vehicles.

5. Finally, while the report says that the technologies to stabilize emissions at current values by 2050 are, in principle, available, it observes that they are not for reductions below this level, and thus calls for:

A massive increase of energy technology Research, Development and Demonstration (RD&D) is needed in the coming 15 years, in the order of USD 10-100 billion per year.

In short, the IEA report should serve as a reminder that the challenge of mitigation is significant and costly. Consequently,the politics of adopting mitigation policies will continue to be difficult (to put it mildly). Efforts to couch mitigation policies as low cost (in the short term) or of immediate benefit will likely fail, because presently this simply is not true. Strategies that will have greater prospects for success will those that align the short term costs with short term benefits, by broadening the focus of mitigation policies beyond a narrow focus on long-term climate change, or, by capitalizing on technological advances that do in fact lead to demonstrable short-term benefits by reducing the costs experienced by consumers and voters.

Until this lesson is learned, climate policy will continue in its current form.

Posted on June 6, 2008 06:54 AM View this article | Comments (2)
Posted to Author: Pielke Jr., R. | Climate Change | Energy Policy | Technology Policy

June 04, 2008

A Few Bits on Cap and Trade

The U.S. Senate is debating a cap and trade bill this week and next. Anyone wanting a look at the debate can find it on CSPAN-2.

Meantime here are a few minor related items:

I reviewed Earth: The Sequel by Fred Krupp and Miriam Horn of the Environmental Defense Fund. Unfortunately, the book adds little to understanding of or debate on cap and trade. My review can be found at Nature Reports: Climate Change here.

Monday's Denver Post has a column by David Harsanyi (opposing the cap and trade bill) in which he quotes from an analysis I did of the effectiveness of the Clean Development Mechanism (CDM) of the Kyoto Protocol for reducing carbon dioxide emissions. Unfortunately he confuses my analysis of the effect of the CDM with an assessment of the entire Protocol. For that analysis he would have wanted to look at a 1998 paper by Tom Wigley, and make a few adjustments based on actual participation and performance of Kyoto. The amount of delay in emissions from all of Kyoto would be measured in months not days.

Posted on June 4, 2008 08:11 AM View this article | Comments (4)
Posted to Author: Pielke Jr., R. | Climate Change | Energy Policy | Technology Policy

June 03, 2008

Idealism vs. Political Realities

David Cox writes in the Guardian on climate change: "It's surely time for a change of tack. Or should we just wring our hands?"

A further excerpt:

Perhaps, it's time to get real. Climate change activists should come to appreciate what religious reformers, communist revolutionaries and other utopian visionaries have learned before them. You can't change human behaviour in the interests of the supposed greater good.
Nonetheless, warming hasn't gone away, even if its character is less clear-cut than has been suggested by those urging us to make obeisance to it. What should we do about it?

The answer is surely to switch our efforts away from trying to change human behaviour towards other approaches to the problem. The most obvious is technological research into methods of alleviating warming. Up until now, mentioning this route has been considered a sinful attempt to divert attention from the hairshirt remedies on which the prophets of doom have insisted. Perhaps partly as a result, such research is proving surprisingly skimpy.

He raises a good point, which I'd characterize as, if efforts to put a meaningful price on carbon fail, what is plan B?

Posted on June 3, 2008 09:32 AM View this article | Comments (23)
Posted to Author: Pielke Jr., R. | Climate Change | Energy Policy | Technology Policy

Air Capture in The Guardian

Saturday's Guardian has a story about a potentially important breakthrough in air capture technology:

It has long been the holy grail for those who believe that technology can save us from catastrophic climate change: a device that can "suck" carbon dioxide (CO2) from the air, reducing the warming effect of the billions of tonnes of greenhouse gas produced each year.
Now a group of US scientists say they have made a breakthrough towards creating such a machine. Led by Klaus Lackner, a physicist at Columbia University in New York, they plan to build and demonstrate a prototype within two years that could economically capture a tonne of CO2 a day from the air, about the same per passenger as a flight from London to New York.

The prototype so-called scrubber will be small enough to fit inside a shipping container. Lackner estimates it will initially cost around £100,000 to build, but the carbon cost of making each device would be "small potatoes" compared with the amount each would capture, he said.

The scientists stress their invention is not a magic bullet to solve climate change. It would take millions of the devices to soak up the world's carbon emissions, and the CO2 trapped would still need to be disposed of. But the team says the technology may be the best way to avert dangerous temperature rises, as fossil fuel use is predicted to increase sharply in coming decades despite international efforts. Climate experts at a monitoring station in Hawaii this month reported CO2 levels in the atmosphere have reached a record 387 parts per million (ppm) - 40% higher than before the industrial revolution.

The quest for a machine that could reverse the trend by "scrubbing" carbon from the air is seen as one of the greatest challenges in climate science. Richard Branson has promised $25m (£12.6m) to anyone who succeeds.

Lackner told the Guardian: "I wouldn't write across the front page that the problem is solved, but this will help. We are in a hurry to deal with climate change and will be very hard pressed to stop the train before we get to 450ppm [CO2 in the atmosphere]. This can help stop the train."

My recent paper on the economics and politics of air capture is going to be obsolete before I even get the reviews back!! (Anyone wanting a copy of the paper as submitted just send me an email: pielke@colorado.edu.)

Posted on June 3, 2008 09:22 AM View this article | Comments (4)
Posted to Author: Pielke Jr., R. | Climate Change | Energy Policy | Technology Policy

June 02, 2008

Visually Pleasing Temperature Adjustments

This is a follow up to our continuing discussion of the possible implications of changes to mid-century global average temperatures for conclusions reached by the IPCC AR4, and how scientists react to such changes.

Over at Real Climate they pointed to the following figure as representing "a good first guess at what the change will look like" and asserted that it would have no meaningful implications for the trends in temperature rise since mid-century presented by the IPCC.

independent graph.jpg

Since there was some disagreement here in the comments of an earlier post about how to interpret this graph, I have decided to simply replicate it and then see if I could exactly replicate the graph from the Independent. The data is available here.

The first thing to note is that the Independent graph has a major error which Real Climate did not point out. It says that the smooth curve represents a 5-year average, when in fact, it actually represents a 21-point binomial filter. The difference in smoothing is critically important for interpreting what the graph actually says, and the error confused me and at least one climate scientist writing in our comments.

Here is a replication of the 21-point smoothing generated from the annual values, which will allow for my effort to replicate the graph from the Independent.

smooth seas.jpg

So far so good. But replication of the adjusted curve is a bit tricky as changing data for any one year has implications for the shape of the curve 10 years before that year and 10 years after. Upon trying to create a exact replication of the graph from The Independent, right away I realized that there was a major problem, because adding any increment to where Thompson et al. said it should begin (in 1945) instantly raised the adjusted curve to a point above the unadjusted curve. And as you can see in the Independent graph that at no point does the adjusted curve rise above the unadjusted curve, much less by a significant amount as implied by Thompson et al..

So right away it seems clear that we are not trying to make an adjustment that actually draws on the guidance from Thompson et al. This might seem odd, since the graph is supposed to show a proposed "guess" at the implications of Thompson et al. In any event, with that constraint removed I simply tried to get the best visual fit to the Independent graph that I could. And here is what I came up with.

Now, given the complicated smoothing routine, there is certainly any number of combinations of weird adjustments that will result in a very similar looking curve. (And if anyone from CRU is reading and wants to share with us exactly what you used, and the basis for it, please do so.) The adjustments I used are as follows:

1945 0
1946 0
1947 0
1948 0.1
1949 0.25
1950 0.18
1951 0.18
1952 0.18
1953 0.18
1954 0.16
1955 0.16
1956 0
1957 0
1958 0
1959 0
1960 0

Oh yeah, the effect of these visually pleasing adjustments on the IPCC trend from 1950? Not that it actually means anything given the obvious incorrectness, but it would reduce the trend by about 15%.

Posted on June 2, 2008 08:00 AM View this article | Comments (20)
Posted to Author: Pielke Jr., R. | Climate Change | Risk & Uncertainty | Scientific Assessments

June 01, 2008

Real Climate on Meaningless Temperature Adjustments

[UPDATE]Real Climate did not like the figure shown below, so I responded to them with the following request, submitted as a comment on their site:

Hi Gavin-
I’d be happy to work from a proposed adjustment directly from you, rather than rely on the one proposed by Steve McIntyre or the one you point to from The Independent.

Thompson et al. write: "The new adjustments are likely to have a substantial impact on the historical record of global-mean surface temperatures through the middle part of the twentieth century."

It is hard to see how temperatures around 1950 can change "substantially" with no effect on trends since 1950, but maybe you have a different view. Lets hear it. Give me some better numbers and I’ll use them.

Their response was to dodge the request:

Response: Nick Rayner, Liz Kent, Phil Jones etc. are perfectly capable of working it out and I’d suggest deferring to their experience in these matters. Whatever they come up with will be a considered and reasonable approach that will include the buoy and drifter issues as well as the post WW-II canvas bucket transition. Second guessing how that will work out in the absence of any actual knowledge would be foolish. - gavin

But doesn't speculation that no changes will be needed to the IPCC trend estimates count as "second guessing," or pointing to a graph in The Independent as likely being correct?

Similarly, in the comments below climate scientist James Annan criticized the graph in this post and when asked to provide an alternative adjustment, he declined to do so.

If these guys know what is "wrong" then they must have an idea about what is "right".

Real Climate writes an entire post responding to Steve McIntyre's recent discussions of buckets and sea surface temperatures, explaining why the issue doesn't really matter, but for some weird reason they can't seem to mention him by name or provide a link to what they are in fact responding to. (If the corrections don't matter, then one wonders, why do them? Thompson et al. seemed to think that the issue matters.)

Real Climate does seem have mastered a passive voice writing style, however. Since they did have the courtesy to link here, before calling me "uninformed" (in deniable passive voice of course), I though a short response was in order.

Real Climate did not like our use of a proposed correction suggested by He Who Will Not Be Named. So Real Climate proposed another correction based on a graphic printed in The Independent. Never mind that the correction doesn't seem to jibe with that proposed by Thompson et al., but no matter, we used the one suggested by Mr. Not-To-Be-Named so lets use Real Climate's as well and see what difference it makes to temperature trends since 1950. Based on what Real Climate asserts (but oddly does not show with numbers), you'd think that their proposed adjustment results in absolutely no change to mid-20th century trends, and indeed anyone suggesting otherwise is an idiot or of ill-will. We'll lets see what the numbers show.

The graph below shows a first guess at the effects of the Real Climate adjustments (based on a decreasing adjustment from 1950-60) based on the graphic in The Independent.

Real Climate Adjustment.jpg

What difference to trends since 1950 does it make? Instead of the about 50% reduction in the 1950-2007 trend from the first rough guess from you-know-who, Real Climate's first guess results in a reduction of the trend by about 30%. A 30% reduction in the IPCC's estimate in temperature trends since 1950 would be just as important as a 50% reduction, and questions of its significance would seem appropriate to ask. But perhaps a 30% reduction in the trend would be viewed as being "consistent with" the original trend ;-)

Try again Real Climate. And next time, his name is STEVE MCINTYRE -- and his blog is called CLIMATE AUDIT. There is a lot of science and civil discussion there, with a healthy mix of assorted experts and a range of ordinary folks. Questioning scientific conclusions is a lot healthier for science than rote defense, but we all learned that in grad school, didn't we?

Posted on June 1, 2008 05:03 PM View this article | Comments (25)
Posted to Author: Pielke Jr., R. | Climate Change | Prediction and Forecasting | Scientific Assessments

May 29, 2008

Does the IPCC’s Main Conclusion Need to be Revisited?

Yesterday Nature published a paper by Thompson et al. which argues that a change in the observational techniques for taking the temperatures of the oceans led to a cold bias in temperatures beginning in the 1940s. The need for the adjustment raises an interesting, and certainly sensitive, question related to the sociology and politics of science: Does the IPCC's main conclusion need to be revisited?

The Nature paper states of the effects of the bias on temperature measurements:

The adjustments immediately after 1945 are expected to be as large as those made to the pre-war data (.0.3 C; Fig. 4), and smaller adjustments are likely to be required in SSTs through at least the mid-1960s.

Thompson et al. do not provide a time series estimate on the effects of the bias on the global temperature record, but Steve McIntyre, who is building an impressive track record of analyses outside the peer-review system, discussed this topic on his weblog long before the paper appeared in Nature, and has proposed an adjustment to the temperature record (based on discussions with participants on his blog). Steve’s adjustment is based on assuming:

that 75% of all measurements from 1942-1945 were done by engine inlets, falling back to business as usual 10% in 1946 where it remained until 1970 when we have a measurement point - 90% of measurements in 1970 were still being made by buckets as indicated by the information in Kent et al 2007- and that the 90% phased down to 0 in 2000 linearly.

The effects of McIntyre’s proposed adjustments (on the UKMET global temperature record) are shown in the following figure.

Other adjustments are certainly plausible, and will certainly be proposed and debated in the literature and on blogs (McIntyre discusses possible implications of the adjustments in this post.). But given how much research has been based on the existing global temperature record, it seems likely that many studies will be revisited in light of the Nature paper. In a comment in Nature that accompanies Thompson et al., Forest and Reynolds suggest:

The SST adjustment around 1945 is likely to have far-reaching implications for modelling in this period.

In the figure above, the trend in the unadjusted data (1950-present) is 0.11 Deg C per decade (slightly lower than reported by IPCC AR4, due to the recent downturn), and after the adjustments are applied the trend drops by just about half, to 0.06 Deg C per decade.

And this brings us to the IPCC. In 2007 the IPCC (PDF) concluded that:

Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations

I interpret "mid-20th century" to be 1950, and "most" to be >50%. This means that the 2007 IPCC attributed more than 0.06 Deg per decade of the temperature increase since 1950 to increasing greenhouse gases. But we know now that the trend since 1950 included a spurious factor due to observational discontinuities, which reduces the entire trend to 0.06. So logically, if the proposed adjustment is in the ballpark, it would mean that one of the following statements must be true in order for the IPCC statement to still hold:

A. The entire trend of 0.06 per decade since 1950 should now be attributed to greenhouse gases (the balance of 0.06 per decade)

B. Only >0.03 per decade can be attributed to greenhouse gases (the "most" from the original statement)

C. The proposed adjustment is wildly off (I’d welcome other suggestions for an adjustment)

D. The IPCC statement needs to be fundamentally recast

So which is it?

PS. To ensure that this blog post is not misinterpreted, note that none of the mitigation or adaptation policies that I have advocated are called into question based on the answer that one gives to the question posed in the title.

Posted on May 29, 2008 08:10 AM View this article | Comments (14)
Posted to Author: Pielke Jr., R. | Climate Change | Science + Politics | Scientific Assessments

May 28, 2008

Meantime, Back in the Real World: Power Plant Conversion Rates

A reader writes in with positive things to say, but notes that as interesting as it is to see our focus on technical issues like the short-term predictive capability of models and the fidelity of IPCC pre/post/SRES scenarios we may also balance that out with some bigger picture stuff.

To that I say: guilty as charged, fair enough. I'll be returning to the short-term prediction stuff before long, but for today's big picture perspective, consider the following points on the scale of the mitigation challenge.

The Center for Global Development estimates that there are 25,339 power plants around the world that emit carbon dioxide. If the world starts replacing or converting these plants to carbon free energy production at the rate of one plant per day, then it will take 69 years to make all of these power plants carbon neutral, and an 80% conversion would take 56 years. If you'd like assume that most emissions come from the largest plants, you can cut those numbers in half or even by 2/3 and the point remains. At a conversion rate of one plant per week -- using only the top 1/3 emitters -- it would take 145 years to convert 80% of these 1/3 (162 years to convert the entire 1/3).

But energy production from fossil fuel power plants is of course increasing, so these are conservative numbers. The rate of conversion from carbon dioixde emitting power plants currently is negative (they are growing in number, at a rate of, what, several per week? Good data sources appreciated in the comments), so the conversion clock is running in reverse. And, oh yeah, power plant emissions according to CGD are 29% of the global total.

The point of this post is not that mitigation is impossible, but that it arguably is much, much harder a challenge than typically advertised. Any guesses on when the power plant conversion rate will become positive, and a what rate it will occur? Will it occur at all?

Posted on May 28, 2008 08:51 AM View this article | Comments (4)
Posted to Author: Pielke Jr., R. | Climate Change | Energy Policy | Technology Policy

May 25, 2008

IPCC Scenarios and Spontaneous Decarbonization

Joe Romm has helpfully posted up his full reply to Nature on PWG (PDF), and we are happy to link to it as promised. And after reading Joe's original letter and his comments, the source of his complaint -- and confusion -- is now clear. This post explains that Joe has confused the differences between different IPCC SRES scenarios with spontaneous decarbonization within each individual scenario.

Figure 1.png

The Figure above is from our Nature paper. It shows for the six SRES families (A1B, A1FI, A1T, A2, B1, B2) cumulative emissions to 2100. For now lets ignore the light blue part of each bar (which represents the spontaneous or automatic decarbonization that we discuss in the paper, and which I return to below).

Joe Romm points out in his critique:

The Special Report on Emission Scenarios (SRES), which the Commentary cites, makes clear that while the SRES scenarios don’t technically have climate policies, they can and do have energy efficiency and decarbonization policies, which are the same thing. That’s clear from examining the B1 scenario, which includes aggressive policies that help limit total global warming to about 2°C

He is correct in this assertion. The effect of these policies in the B1 sceanrio can be seen in the difference between the height of the green plus red (G+R) parts of the B1 bar and the same G+R portion of the bars for the other scenarios. Clearly, the B1 G+R is closer to the dotted line than any of the others (though A1T is also close). The "energy and decarbonization policies" that Joe Romm refers to are those that account for the difference in height between the G+R parts of the bars in our graph across scenarios -- which is completely different than the assumptions of automatic decarbonization within each scenario which are reflected in the light blue parts of the bars.

Automatic decarbonization occurs in the IPCC scenarios not because of specific policies that the report discusses, but because of assumptions that it uses within individual scenarios (specifically, assumptions of decreasing carbon and energy intensities). Whatever policies are associated with these assumptions are not discussed by the IPCC. The decarbonization of the global economy reflected by the light blue portions of the bars in the figure above are indeed accurately characterized as being "automatic" or "spontaneous."

In its editorial discussing our paper, Nature clearly understood this. Joe Romm apparently does not. He has confused the differences between aggregate emissions across scenarios with assumptions of automatic decarbonization within scenarios.

Now that Joe has released his original letter to Nature, it is clear why they asked him to correct his error of interpretation. It is also clear why his claims that we have made an error in our analysis is incorrect.

Posted on May 25, 2008 03:52 PM View this article | Comments (18)
Posted to Author: Pielke Jr., R. | Climate Change | Energy Policy | Technology Policy

A Familiar Pattern is Emerging

This post provides a good example how some climate bloggers try to shut down debate over policy options by personalizing policy debates.

William Nordhaus, one of the leading economists who has worked on climate change, has a new book coming out, which is good news for anyone interested in the subject. His book was reviewed in The New York Review of books by Freeman Dyson.

But rather than take on the arguments made by Nordhaus, Real Climate and Joseph Romm attack Nordhaus' arguments by proxy. They attack Freeman Dyson for invoking arguments raised by Nordhaus. In the process they ignore the substance of the issues and turn the issue into a referendum on an individual with whom they have policy differences. This tag-team smear job is becoming a bit too familiar.

In Nordhaus' book he discusses five policy approaches, summarized by Freeman Dyson as follows:

Nordhaus examines five kinds of global-warming policy, with many runs of DICE for each kind. The first kind is business-as-usual, with no restriction of carbon dioxide emissions—in which case, he estimates damages to the environment amounting to some $23 trillion in current dollars by the year 2100. The second kind is the "optimal policy," judged by Nordhaus to be the most cost-effective, with a worldwide tax on carbon emissions adjusted each year to give the maximum aggregate economic gain as calculated by DICE. The third kind is the Kyoto Protocol, in operation since 2005 with 175 participating countries, imposing fixed limits to the emissions of economically developed countries only. Nordhaus tests various versions of the Kyoto Protocol, with or without the participation of the United States.
The fourth kind of policy is labeled "ambitious" proposals, with two versions which Nordhaus calls "Stern" and "Gore." "Stern" is the policy advocated by Sir Nicholas Stern in the Stern Review, an economic analysis of global-warming policy sponsored by the British government.[*] "Stern" imposes draconian limits on emissions, similar to the Kyoto limits but much stronger. "Gore" is a policy advocated by Al Gore, with emissions reduced drastically but gradually, the reductions reaching 90 percent of current levels before the year 2050. The fifth and last kind is called "low-cost backstop," a policy based on a hypothetical low-cost technology for removing carbon dioxide from the atmosphere, or for producing energy without carbon dioxide emission, assuming that such a technology will become available at some specified future date. According to Nordhaus, this technology might include "low-cost solar power, geothermal energy, some nonintrusive climatic engineering, or genetically engineered carbon-eating trees."

What do Real Climate and Joseph Romm do? Rather than engage the substance of the policy arguments, they go on the attack, with Real Climate using the term "b#ll&hit" and Romm "unmitigated disinformation." Of course the policy issues that they don't like -- discount rates, cost estimates, air capture -- all come from Nordhaus, not Dyson. But rather than engage the substance they viciously attack an individual.

The only apparently original view from Dyson that Real Climate takes issue with is when Dyson notes that (in a second book discussed in the review, by Ernesto Zedillo) chapters by Richard Lindzen and Stefan Rahmstorf (of Real Climate) are both unsatisfactory:

These two chapters give the reader a sad picture of climate science. Rahmstorf represents the majority of scientists who believe fervently that global warming is a grave danger. Lindzen represents the small minority who are skeptical. Their conversation is a dialogue of the deaf. The majority responds to the minority with open contempt.

A sad picture indeed.

Posted on May 25, 2008 03:02 PM View this article | Comments (12)
Posted to Author: Pielke Jr., R. | Climate Change | Science + Politics

May 23, 2008

Homework Assignment: Solve if you Dare

The graph above shows three trend lines.

BLUE: Temperature Trend prediction from the 1990 IPCC report
RED: Temperature Trend prediction from the 2007 IPCC report
GREEN: Observed Trend for 2001-2007 (from average of four obs datasets)

All data is as described in this correspodence (PDF).

Your assignment:

Which IPCC prediction is the trend observed 2001-2007 more consistent with and why? Show your work!

You are free to bring in whatever information and use whatever analysis that you want.

Posted on May 23, 2008 12:08 AM View this article | Comments (24)
Posted to Author: Pielke Jr., R. | Climate Change | Prediction and Forecasting | Scientific Assessments

May 22, 2008

Nature Letters on PWG

The 8 May 2008 issue of Nature published 4 letters in response to the Pielke, Wigley, and Green commentary on IPCC scenarios (PDF). This provides a few excerpts from and reactions to these letters.

Vaclav Smil of the University of Manitoba writes:

I largely agree with the overall conclusion of Pielke et al. that the IPCC assessment is overly optimistic, but I fear that the situation is even worse than the authors imply.

Smil is realistic about the challenge of mitigation:

The speed of transition from a predominantly fossil-fuelled world to conversions of renewable flows is being grossly overestimated: all energy transitions are multigenerational affairs with their complex infrastructural and learning needs. Their progress cannot substantially be accelerated either by wishful thinking or by government ministers’ fiats.

But pessimistic about action:

Consequently, the rise of atmospheric CO2 above 450 parts per million can be prevented only by an unprecedented (in both severity and duration) depression of the global economy, or by voluntarily adopted and strictly observed limits on absolute energy use. The first is highly probable; the second would be a sapient action, but apparently not for this species.

Christopher Field, from Stanford University agrees with our analysis and its implications:

The trends towards increased carbon and energy intensity may or may not continue. In either case, we need new technologies and strategies for both endogenous and policy-driven intensity improvements. Given recent trends, it is hard to see how, without a massive increase in investment, the requisite number of relevant technologies will be mature and available when we need them.

Richard Richels, of the Electric Power Research Institute, Richard Tol, of the Economic and Social Research Institute (Ireland), and Gary Yohe, of Wesleyan University support our analysis and our interpretation of its significance:

Pielke et al. show that the 2000 Special Report on Emissions Scenarios (SRES) reflects unrealistic progress on both the supply and demand sides of the energy sector. These unduly optimistic baselines cause serious underestimation of the costs of policy-induced mitigation required to achieve a given stabilization level.
This is well known among experts but perhaps not to the public, which may explain why some politicians overstate the impact of their (plans for) climate policy, and why others argue incorrectly that ‘available’ off-the-shelf technologies can reduce emissions at very little or no cost.

They also make an absolutely critical point about climate policy – it is necessarily incremental and adaptive:

The focus of policy analysis should not be on what to do over the next 100 years, but on what to do today in the face of many important long-term uncertainties. The minute details of any particular scenario for 2100 are then not that important. This can be achieved through an iterative risk management approach in which uncertain long-term goals are used to develop short-term emission targets. As new information arises, emission scenarios, long-term goals and short-term targets are adjusted as necessary. Analyses would be conducted periodically (every 5–10 years), making it easier to distinguish autonomous trends from policy-induced developments — a major concern of Pielke and colleagues. If actual emissions are carefully monitored and analysed, the true efficacy and costs of past policies would be revealed and estimates of the impact of future policy interventions would be less uncertain.
Such an approach would incorporate recent actions by developed and developing countries. In an ‘act then learn’ framework, climate policy is altered in response to how businesses change their behavior in reaction to existing climate policies and in anticipation of future ones. This differs from SRES-like analyses, which ignore the dynamic nature of the decision process and opportunities for mid-course corrections as they compare scenarios without policy with global, century-long plans.

Ottmar Edenhofer, Bill Hare, Brigitte Knopf, Gunnar Luderer Potsdam of the Institute for Climate Impact Research (Germany) suggest that the range of rates for the future decarbonization of energy in the IPCC reports is in fact appropriate:

Over the past 30 years, the decrease in energy intensity has been 1.1% a year — well above the 0.6% a year assumed in 75% of the energy scenarios assessed by the IPCC.
Developments in China since 2000 do raise concerns that the rate of decrease in energy and carbon intensity could slow down, or even be reversed. However, similar short-term slow-downs in technical progress have occurred in the past, only for periods of more rapid development to compensate for them. India, for example, does not show the decreasing trend in energy efficiency seen in China.

The figure of 75% of scenarios of the IPCC assuming 0.6% per year decrease in energy intensity is difficult to interpret. But here is what the IPCC itself says on this (WGIII Ch. 3, p. 183 PDF):

In all scenarios, energy intensity improves significantly across the century – with a mean annual intensity improvement of 1%. The 90% range of the annual average intensity improvement is between 0.5% and 1.9% (which is fairly consistent with historic variation in this factor). Actually, this range implies a difference in total energy consumption in 2100 of more than 300% – indicating the importance of the uncertainty associated with this ratio.

So if 5% fall below 0.5%, it is hard to understand what the authors mean by "0.6% a year assumed in 75% of the energy scenarios assessed by the IPCC." Contrary to the other letters Edenhofer et al. conclude:

The IPCC’s main policy conclusions stand: present technologies can stop the rise in global emissions.

The final letter is from Joseph Romm, of the Center for America Progress. He chooses to parse what is meant by the term "climate policies" in the vernacular of the IPCC:

They criticize the IPCC for implicitly assuming that the challenge of reducing future emissions will mostly be met without climate policies. But the IPCC’s Special Report on Emissions Scenarios makes clear that, although the scenarios don’t technically have climate policies, they can and do have energy efficiency and decarbonization policies, which amount to the same thing

It is not clear why this semantic point matters for interpreting our analysis as it has no implications for either our technical analysis or its interpretation. Of course, the IPCC defined the notion of "climate policies" quite precisely for a reason -- because the policies that relate to improved energy efficiency and decarbonization assumed by the IPCC to occur in their scenarios in the absence of climate policy mean that these other policies would be implemented with no effort focused on the stabilization of greenhouse gases in the atmosphere (no cap and trade, no Kyoto, no carbon tax, etc. etc.). These policies, whatever they are, would happen spontaneously or automatically without any concern for climate. This assumption was explicit in the terms of reference for the IPCC SRES exercise for the purpose of clearly identifying the marginal benefits and costs of climate-specific policies.

Romm then simply repeats the conclusions of the IPCC:

the IPCC report makes clear that we have the necessary technologies, or soon will, and focuses on creating the conditions for rapid technological deployment

Interestingly, with a letter in Nature Romm, who has been a strong critic of our paper on his blog, had a perfect opportunity to explain what might have been incorrect in our technical analysis, and did not. We can assume that he was unable to find any flaws and thus chose to focus on the implications of the analysis, which he does not enagage, choosing simply to restate a position that he held before our paper came out.

As can be seen clearly in the letters, there is not a consensus among energy policy experts on the role of technological innovation in efforts to mitigate climate change. This is a debate which has only just begun, and for which there are a range of legitimate and informed points of view, despite the efforts of some to demagogue anyone who disagrees with their views.

World Bank and UK Government on Climate Change Implications of Development

The World Bank and UK government issued a report today titled, "Strategies For Sustained Growth And Inclusive Development." Here is what the report says about the implications for climate change of development in the developing world (p. 86), something that the report calls absolutely necessary:

Clearly the advanced countries are at per capita [carbon dioxide] output levels that, if replicated by the developing world, would be dramatically in excess of safe levels. World carbon emissions are now at about twice the safe level, meaning that if the current output is sustained, the CO2 stock in the atmosphere will rise above safe levels in the next 40 years. The figures for a range of countries, including developing countries, are shown in Figure 9.
If the developing countries did not grow, then safe levels of emissions would be achieved by reducing advanced country emissions by a factor of two or a little more. But with the growth of the developing countries, the incremental emissions are very large because of the size of the populations. To take the extreme case, if the whole world grew to advanced country incomes and converged on the German levels of emissions per capita, then to be safe from a warming standpoint, emissions per capita would need to decline by a factor of four. Reductions of this magnitude with existing technology are either not possible, or so costly as to be certain of slowing global and developing country growth.

What these calculations make clear is that technology is the key to accommodating developing country and global growth. We need to lower the costs of mitigation. Put differently, we need to build more economic value on top of a limited energy base. For that we need new knowledge.

What actions does the report call for (p. 90)?

The Commission recommends the following nine steps. Taken together, they will cut emissions, thereby staving off some of the worst dangers of global warming. They will reveal more about the cost of cutting emissions, and they will encourage new technologies that reduce these costs. These steps are also fair.
1. The advanced economies should cut emissions first and they should do so aggressively. This will slow the accumulation of carbon in the atmosphere. It will also reveal a great deal about how much it truly costs to cut carbon emissions.

2. More generous subsidies should be paid to energy-efficient technologies and carbon reduction technologies, which will reduce the cost of mitigation.

3. Advanced economies should strive to put a price on carbon.

4. The task of monitoring emissions cuts and other mitigation measures should be assigned to an international institution, which should begin work as soon as possible.

5. Developing countries, while resisting long-term target-setting, should offer to cut carbon at home if other countries are willing to pay for it. Such collaborations take place through the Clean Development Mechanism provisions in the Kyoto protocol. Rich countries can meet their Kyoto commitments by paying for carbon cuts in poorer countries.

6. Developing countries should promise to remove fuel subsidies, over a decent interval. These subsidies encourage pollution and weigh heavily on government budgets.

7. All countries should accept the dual criteria of efficiency and fairness in carbon mitigation. In particular, richer countries, at or near high-income levels, should accept that they will each have the same emissions entitlements per head as other countries.

8. Developing countries should educate their citizens about global warming. Awareness is already growing, bringing about changes in values and behavior.

9. International negotiations should concentrate on agreeing to carbon cuts for more advanced economies, to be achieved 10 or 15 years hence.
These mitigation efforts should be designed so as to reveal the true costs of mitigation.

Interestingly, the report calls for developing countries to "resist long-term target setting" while at the same time expressing skepticism about the "true costs of mitigation." The report shows that there is a wide range of views on what sort of mitigation actions make sense in the debate over climate policy that cannot be captured by the facile "denialist-alarmist" dichotomy that some observers would like to enforce on the debate. One oversight is that the report does not address the issue of adaptation.

IPCC Predictions and Politics

The May 1, 2008 issue of New Scientist magazine has an interesting article that parallels some of the discussions that we’ve had on this site lately. Here is an interesting excerpt:

"Politicians seems to think that the science is a done deal," says Tim Palmer, "I don’t want to undermine the IPCC, but the forecasts, especially for regional climate change, are immensely uncertain".
Palmer is a leading climate modeller at the European Centre for Medium-Range Weather Forecasts in Reading, UK, and he does not doubt that the Intergovernmental Panel on Climate Change (IPCC) has done a good job alerting the world to the problem of global climate change. But he and his fellow climate scientists are acutely aware that the IPCC's predictions of how the global change will affect local climates are little more than guesswork. They fear that if the IPCC's predictions turn out to be wrong, it will provoke a crisis in confidence that undermines the whole climate change debate.

The IPCC's forecasts could be wrong in many different ways, over different time periods and spatial scales, including underestimating future changes. And it is not even clear that scientists involved with the IPCC have a collective view on what it would even mean for the IPCC to be "wrong". As we've argued here often, action on climate change makes sense even if the predictions of the IPCC are not yet perfect. But this is a hard case to make when defenders of those predictions allow no room for imperfections to be seen, or questions to be asked.

Posted on May 22, 2008 01:06 AM View this article | Comments (12)
Posted to Author: Pielke Jr., R. | Climate Change | Prediction and Forecasting | Science + Politics

May 21, 2008

An Inconsistent With Spotted, and Defended

Readers following recent threads know that I've been looking for instances where scientists make claims that some observations are "inconsistent with" the results from climate models. The reason for such a search is that it is all too easy for modelers to claim that anything and everything under the sun is "consistent with" their predictions, sometimes to avoid the perception of a loss of credibility in the political battle over climate change.

I am happy to report that claims of "inconsistent with" do exist. Here is an example from a paper just out by Knutson et al. in Nature Geoscience:

Our results using the ensemble-mean global model projections (Fig. 4) are inconsistent with the notion of large, upward trends in tropical storm and hurricane frequency over the twentieth century, driven by greenhouse warming.

The climate modelers at Real Climate apparently don't like the phrase "inconsistent with" in the context of models and try to air brush it away when they write of Knutson et al.:

. . .we know that (i) the warming [of the oceans] is likely in large part anthropogenic, and (ii) that the recent increases in TC frequency are related to that warming. It hardly seems a leap of faith to put two-and-two together and conclude that there is likely a relationship between anthropogenic warming and increased Atlantic TC activity.

Knutson et al. respond in the comments that this in fact is not how to interpret their paper, and -- kudos to them -- take strong, public issue with the weaselly words implying a connection that they don't show (emphasis added in the below, and I've copied the whole comment for the entire context):

Mike [Mann],
Statement (i), that "the warming [of the tropical Atlantic Ocean] is likely in large part anthropogenic." is reasonable, taking "anthropogenic" to mean "greenhouse gas", given the work of Santer et al (2006, PNAS), Knutson et al (2006, J. Clim.), and Gillett et al (2008, G.R.L.). To quote from Gillett et al:

…our results indicate that greenhouse gas increases are indeed likely the dominant cause of [tropical Atlantic] warming…

However, statement (ii), that "the recent increases in [Atlantic] TC (tropical cyclone) frequency are related to that warming" is vague – with "related to" allowing an interpretation that includes anything from a negative relationship, to a minor contribution, to local SST warming being the dominant dynamical control on TC frequency increase. Some might interpret "related to" to mean "are dominantly controlled by", and we think the evidence does not justify such a strong statement. In particular, the results of Knutson et al (2008) do not support such an attribution statement,if one focuses on the greenhouse gas part of the anthropogenic signal. Quoting from page 5 of the paper:

Our results using the ensemble-mean global model projections (Fig. 4) are inconsistent [emphasis added] with the notion of large, upward trends in tropical storm and hurricane frequency over the twentieth century, driven by greenhouse warming

We agree that TC activity and local Atlantic SSTs are correlated but do not view this correlation as implying causation. The alternative, consistent with our results, is that there is a causal nonlocal relationship between Atlantic TC activity and the tropical SST field. The simplest version uses the difference between Atlantic and Tropical-mean SST changes as the predictor (Swanson 2008, Non-locality of Atlantic tropical cyclone intensities, G-cubed, 9, Q04V01). This picture is also consistent with non-local control on wind shear (e.g. Latif et al 2007, G.RL.), atmospheric stability (e.g., Shen et al 2000, J. Clim.) and maximum potential intensity (e.g., Vecchi and Soden, 2007, Nature).

We view the SST change in the tropical Atlantic relative to the rest of the tropics as the key to these questions. Warming in recent decades has been particularly prominent in the northern tropical Atlantic, but such a pattern is not evident in the consensus of simulations of the response to increasing greenhouse gases. So, whether changes in Atlantic SST relative to the rest of the tropics - that according to our hypothesis have resulted in the changes in hurricane activity - were primarily caused by changes in radiative forcing, or whether they were primarily caused by internal climate variability, or (most likely) whether both were involved, is obviously an important issue, but this is not addressed by our paper

Now a word of caution -- Knutson et al. 2008 is by no means the last word on hurricanes and global warming, and the issue remains highly contested, and will remain so for a long time. Of course, you heard that (accurate) assessment of the state of this particular area of climate science here a long time ago (PDF;-)

Knutson et al. is notable because it clearly identifies observations "inconsistent with" what the models report which should give us greater confidence in research focused on generating climate predictions. We should have greater confidence because if practically everything observed is claimed to be "consistent with" model predictions, then climate models are pretty useless tools for decision making.

May 19, 2008

Do IPCC Temperature Forecasts Have Skill?

[UPDATE] Roger Pielke, Sr. tells us that we are barking up the wrong tree looking at surface temperatures anyway. He says that the real action is in looking at oceanic heat content, for which predictions have far less variability over short terms than do surface temperatures. And he says that observations of accumulated heat content over the past 4 years "are not even close" to the model predictions. For the details, please see for your self at his site.]

"Skill" is a technical term in the forecast verification literature that means the ability to beat a naïve baseline when making forecasts. If your forecasting methodology can’t beat some simple heuristic, then it will likely be of little use.

What are examples of such naïve baselines? In weather forecasting historical climatology is often used. So if the average temperature in Boulder for May 20 is 75 degrees, and my prediction is for 85 degree, then any observed temperature below 80 degrees will mean that my forecast had no skill. In the mutual fund industry stock indexes are examples of naive baselines used to evaluate performance of fund managers. Of course, no forecasting method can always show skill in every forecast, so the appropriate metric is the degree of skill present in your forecasts. Like many other aspects of forecast verification, skill is a matter of degree, and is not black or white.

Skill is preferred to "consistency" if only because the addition of bad forecasts to a forecasting ensemble does not improve skill unless it improves forecast accuracy, which is not the case with certain measures of "consistency," as we have seen. Skill also provides a clear metric of success for forecasts, once a naïve baseline is agreed upon. As time goes on, forecasts such as those issued by the IPCC should tend toward increasing skill, as the gap between a naive forecast and a prediction grows. If a forecasting methodology shows no skill then it would be appropriate to question the usefulness and/or accuracy of the forecasting methodology.

In this post I use the IPCC forecasts of 1990, 2001, and 2007 to illustrate the concept of skill, and to explain why it is a much better metric that "consistency" to evaluate forecasts of the IPCC.

The first task is to choose a naïve baseline. This choice is subjective and people often argue over it. People making forecasts usually want a baseline that is easy to beat, people using or paying for forecasts often want a more rigorous baseline. For this exercise I will use the observed temperature trend over the 100 years ending in 2005, as reported by the 2007 IPCC, which is 0.076 degrees per decade. So in this exercise the baseline that the IPCC forecasts have to beat is a naïve assumption that future temperature increases will increase by the same rate as has been observed over the past 100 years. Obviously, one could argue for a different naïve baseline, but this is the one I’ve chosen to use.

I will also use the ensemble average "best guess" from the IPCC for the most appropriate emissions scenario as the prediction. And for observations I will use the average value from the four main group tracking global temperature trends. These choices could be made differently, and a more comprehensive analysis would explore different ways to do the analysis.

So then, using these metrics how does the IPCC 1990 best estimate forecast for future increases in temperature compare for 1990-2007? The figure below shows that the IPCC forecast, while over-predicting the observed trend, outperformed this naïve baseline. So the forecast can be claimed to be skillful, but not by very much.

A more definitive example of a skillful forecast is the 2001 IPCC prediction, which the following figure shows demonstrated a high degree of skill.

Similarly, the 2000-2007 forecast of the IPCC 2007 also shows a high degree of skill, as seen in the next figure.

But in 2008 things get interesting. With data from 2008 included, rather than ending in 2007, then the 2007 IPCC forecast is no longer skillful, as shown below.

If one starts the IPCC predictions in 2001, then the lack of skill is even greater, as seen below.

What does all of this mean for the ability of the IPCC to predict longer-term climate change? Perhaps nothing, as many scientists would claim that it makes no sense to discuss IPCC predictions on time scales less than 20 or 30 years. If so, then it would also be inappropriate to claim that IPCC forecasts on the shorter scales are skillful or accurate. One way to interpret the recent Keenlyside et al. paper in Nature is that their analysis suggests that the IPCC predictions of future temperature evolution won't be skillful unless they account for various factors not included in the IPCC predictions.

The point of this exercise is to show that there are simple, unambiguous alternatives to using the notion of "consistency" as the basis for comparing IPCC forecasts with observations. "Consistency" between models and observations is a misleading, and I would say fairly useless way to talk about climate forecasts. Measures of skill provide an unambiguous way to evaluate how the IPCC is doing over time.

But make no mistake, the longer the IPCC forecasts lie in a zone of "no skill" -- which the most recent ones (2007) currently do (for the time of the forecast to present) -- the more interest they will receive. This time period may be for only one more month, or perhaps many years. I don't know. This situation creates interesting incentives for forecasters who want their predictions to show skill.

Posted on May 19, 2008 09:21 AM View this article | Comments (42)
Posted to Author: Pielke Jr., R. | Climate Change | Prediction and Forecasting | Scientific Assessments

Old Wine in New Bottles

The IPCC will be using new scenarios for its future work, updating those produced in 2000, the so-called SRES scenarios. This would be good news, since, as we argued in Nature last month, the IPCC scenarios contain some dubious assumptions (PDF). But from the looks of it, it does not appear that much has changed, excpet the jargon. The figure below compares the new scenarios as presented in a report from a meeting of the IPCC held last month (source: PDF) with those from the 2000 IPCC SRES report. I have presented the two sets of scenarios on the same scale to facilitate comparison. Do they look much different to you?

May 16, 2008

The Helpful Undergraduate: Another Response to James Annan

In his latest essay on my stupidity, climate modeler James Annan made the helpful suggestion that I consult a "a numerate undergraduate to explain it to [me]." So I looked outside my office, where things are quiet out on the quad this time of year, but as luck would have it, I did find a young lady named Megan, who just happened to be majoring in mathematics who agreed to help me overcome my considerable ignorance.

The first thing I had to do was explain to Megan the problem we are looking at. I told her that we had 55 estimates of a particular quantity, with a mean of 0.19 and standard deviation of 0.21. At the same time we had 5 different observations of that same quantity, with a mean of –0.07 and standard deviation of 0.07. I wanted to know how similar or different from each other these two sets of data actually were.

I explained to her that James Annan, a modest, constructive, and respectful colleague of mine who happened to be a climate modeler ("Cool" she said), had explained that the best way to compare these datasets was to look at the normal distribution associated with the data (N(0.19. 0.21) and plot on that distribution the outlying value from the smaller dataset.

Since the outlying value of the observations fell well within the distribution of the estimates, James told us, the two dataset could not be claimed to be different -- case closed, anyone saying anything different must be an ignorant climate denying lunatic.

"Professor Pielke," Megan said, "You are funny. James surely didn’t react that way, because since he is a climate modeler he must surely recognize that there are many ways to look at statistical problems. We even learned that just this year in our intro stats class. Besides, I can’t imagine a scientific colleague being so rude! You must have misinterpreted him."

Since Megan was being so helpful in my education, I simply replied that we should stick to the stats. Besides, if she really knew that I was a climate denying moron, she might not continue to help me.

Megan said, "There is another way to approach this problem. Have you heard of an unpaired t-test for two different samples? (PDF)"

I replied, "Of course not, I am just a political scientist."

Megan said, "We learned in stats this year that such a test is appropriate for comparing two distributions with equal variance to see how similar they are. It is really very easy. In fact you can run these tests online using a simple calculator. Here is one such website that will do all of the work for you, just plug in the numbers."

So we plugged our numbers into the magic website as follows:

Sample 1:

Mean = 0.19
SD = 0.21
N = 55

Sample 2

Mean = -0.07
SD = 0.07
N = 5

And here is what the magic website reported back:

Unpaired t test results
P value and statistical significance:

The two-tailed P value equals 0.0082

By conventional criteria, this difference is considered to be very statistically significant.

Confidence interval:
The mean of Group One minus Group Two equals -0.2600
95% confidence interval of this difference: From -0.4502 to -0.0698

Intermediate values used in calculations:
t = 2.7358
df = 58
standard error of difference = 0.095

"Wow," I said to Megan, "These are lots of numbers. What do they all mean?"

"Well," Megan helpfully replied, "They mean that there is a really good chance that your two distributions are inconsistent with each other."

"But," I protested, "Climate modeler James Annan came up with a different result! And he said that his method was the one true way!"

"You are kidding me again, Professor Pielke," she calmly replied, "Dr. Annan surely recognizes that there are a lot of interesting nuances in statistical testing and using and working with information. There are even issues that can be raised about the appropriateness of test that we performed. So I wouldn't even be too assured that these results are the one true way either. But they do indicate that there are different ways to approach scientific questions. I am sure that Dr. Annan recognizes this, after all he is a climate scientist. But we'll have to discuss those nuances later. I'm taking philosophy of science in the fall, and would be glad to tutor you in that subject as well. But for now I have to run, I am on summer break after all."

And just like that she was gone. Well, after this experience I am just happy that I was instructed to find a smart undergraduate to help me out.

[UPDATE An alert reader notes this comment by Tom C over at James' blog, which is right on the mark:

James -
What you and Roger are arguing about is not worth arguing about. What is worth arguing about is the philosophy behind comparing real-world data to model predictions. I work in the chemical industry. If my boss asked me to model a process, I would not come back with an ensemble of models, some of which predict an increase in a byproduct, some of which predict a decrease, and then claim that the observed concentration of byproduct was "consistent with models". That is just bizarre reasoning, but, of course, such a strategy allows for perpetual CYAing.

The fallacy here is that you are taking models, which are inherently different from one another, pretending that they are multiple measurements of a variable that differ only due to random fluctuations, then doing conventional statistics on the "distribution". This is all conceptually flawed.

Moreover, the wider the divergence of model results, the better the chance of "consistency" with real-world observations. That fact alone should signal the conceptual problem with the approach assumed in your argument with Roger.

Another commenter tries to help out James by responding to Tom C, but in the process, also hits the nail on the head:

I don't see what the problem is, Tom C. It seems obvious that the less specific a set of predictions is, the more difficult it is to invalidate. So yes, consistency doesn't neccessarily mean that your model is meaningful, especially over such short terms.

Right! "Consistent with" is not a meaningful statement. Which is of course where all of this started.

[UPDATE #2]

The figure below shows the IPCC distribution of 55 forecasts N[0.19, 0.21] as the blue curve, and I have invented a new distribution (red curve) by adding a bunch of hypothetical nonsense forecasts such that the distribution is now N[0.19, 1.0].

The blue point represents a hypothetical observation.

According to the metric of evaluating forecasts and observations proposed by James Annan my forecasting ability improved immensely simply by adding 55 nonsense forecasts, since th blue observational point now falls closer to the center of the new (and improved distribution).

ipcc+55.png

Now if James wants to call this an improvement ("more consistent whit" -- "higher statistical significance" -- etc.], but any approach that lends greater consistency by making adding worse forecasts to your distributions fails the common sense test.

[UPDATE #3]

Real Climate says this about a model-observation comparison in a recent paper by Knutson et al. in Nature Geoscience on hurricanes:

The fact that the RCM-based downscaling approach can reproduce the observed changes when fed modern reanalysis data is used by Knutson et al as a 'validation' of the modeling approach (in a very rough sense of the word–there is in fact a non-trivial 40% discrepancy in the modeled and observed trends in TC frequency). But this does not indicate that the downscaled GCM projections will provide a realistic description of future TCs in combination with a multi-model GCM ensemble mean. It only tells us that the RCM can potentially provide a realistic description of TC behavior provided the correct input.

Have a look at the figure below, and the distributions of modeled and observations. Its funny how the differences in these distributions is considered to be "non-trivial" but the larger differences in temperature trends is "not inconsistent with" model predictions. Further proof of the irrelevance of the notion of "consistency."

knutson distro.png

Posted on May 16, 2008 11:55 AM View this article | Comments (102)
Posted to Author: Pielke Jr., R. | Climate Change | Prediction and Forecasting | Risk & Uncertainty

The Politicization of Climate Science

[Update: The ever helpful David Roberts of Grist Magazine points out that an op-ed in the Washington Times yesterday makes the same logical error that I point out in this post below made by Patrick Michaels -- namely that short-term predictive failures obviate the need for action. The op-ed quotes me and says that I am "not previously a global warming skeptic," which is correct, but implies that somehow I am now . . . sorry, wrong. It also quotes my conclusion that climate models are "useless" without the important qualifiers **for decision making in the short term when specific decisions must be made**. Such models are great exploratory scientific tools, and were helpful in bringing the issue of greenhouse gases to the attention of decision makers. I've emailed the author making these points, asking him to correct his piece.]

Here I'd like to explain why one group of people, which we might call politically active climate scientists and their allies, seek to shut down a useful discussion with intimidation, bluster, and name-calling. It is, as you might expect, a function of the destructive politics of science in the global warming debate.

We've had a lot of interest of late in our efforts to explore what would seem to be a simple question:

What observations of the global climate system (over what time scale, with what certainty, etc.) would be inconsistent with predictions of the IPCC AR4?

The motivation for asking this question is of course the repeated claims by climate scientists that this or that observation is "consistent with" such predictions. For claims of consistency between observations and predictions to have any practical meaning whatsoever, they must be accompanied by knowledge of what observations would be inconsistent with predictions. This is a straightforward logical claim, and should be uncontroversial.

Yet efforts to explore this question have been met with accusations of "denialism," of believing that human-caused global warming is "not a problem," of being a "conspiracy theorist." More constructive responses have claimed that questions of inconsistency cannot really be addressed for 20-30 years (which again raises the question why claims of consistency are appropriate on shorter timescales), have focused attention on the various ways to present uncertainty in predictions from a suite of models and also on uncertainties in observations systems, and have focused attention on the proper statistical tests to apply in such situations. In short, there is a lot of interesting subjects to discuss. Some people think that they have all of the answers, which is not at all problematic, as it makes this issue no different than most any other discussion you'll find on blogs (or in academia for that matter).

But why is it that some practicing climate scientists and their allies in the blogosphere appear to be trying to shut down this discussion? After all, isn't asking and debating interesting questions one of the reasons most of us decided to pursue research as a career in the first place? And in the messy and complicated science/politics of climate change wouldn't more understanding be better than less?

The answer to why some people react so strongly to this subject can be gleaned from an op-ed in today's Washington Times by one Patrick Michaels, a well-known activist skeptical of much of the claims made about the science and politics of climate change. Here is what Pat writes:

On May Day, Noah Keenlyside of Germany's Leipzig Institute of Marine Science, published a paper in Nature forecasting no additional global warming "over the next decade."
Al Gore and his minions continue to chant that "the science is settled" on global warming, but the only thing settled is that there has not been any since 1998. Critics of this view (rightfully) argue that 1998 was the warmest year in modern record, due to a huge El Nino event in the Pacific Ocean, and that it is unfair to start any analysis at a high (or a low) point in a longer history. But starting in 2001 or 1998 yields the same result: no warming.

Michaels is correct in his assertion of no warming starting in these dates, but one would reach a different conclusion starting in 1999 or 2000. He continues,

The Keenlyside team found that natural variability in the Earth's oceans will "temporarily offset" global warming from carbon dioxide. Seventy percent of the Earth's surface is oceanic; hence, what happens there greatly influences global temperature. It is now known that both Atlantic and Pacific temperatures can get "stuck," for a decade or longer, in relatively warm or cool patterns. The North Atlantic is now forecast to be in a cold stage for a decade, which will help put the damper on global warming. Another Pacific temperature pattern is forecast not to push warming, either.
Science no longer provides justification for any rush to pass drastic global warming legislation. The Climate Security Act, sponsored by Joe Lieberman and John Warner, would cut emissions of carbon dioxide — the main "global warming" gas — by 66 percent over the next 42 years. With expected population growth, this means about a 90 percent drop in emissions per capita, to 19th-century levels.

He has laid out the bait, complete with reference to Al Gore, claiming that recent trends of no warming plus a forecast of continued lack of warming mean that there is no scientific basis for action on climate change.

There are several ways that one could respond to these claims.

One very common response to these sort of arguments would be to attack Michaels putative scientific basis for his policy arguments. Some would argue that he has cherrypicked his starting dates for asserting no trend. Other would observe that the recent trends in temperature are in fact consistent with predictions made by the IPCC. This latter strategy is exactly the approach used by the bloggers at Real Climate when I first started comparing 2007 IPCC predictions (from 2000) with temperature observations.

The "consistent with" strategy is a potential double-edged sword because it grants Pat Michaels a large chunk of territory in the debate. Once you attack the scientific basis for political arguments that are justified in those terms, you are accepting Michaels claim that the political arguments are in fact a function of the science. So in this case, by attacking Michaels scientific claims, you would be in effect saying

"Yes while it is true that these policies are justified on scientific conclusions, Pat Michaels has his science wrong. Getting the science right would lead to different political conclusions that Michaels arrives at."

Here at Prometheus for a long time we've observed how this dynamic shifts political debates onto scientific debates. Any I discuss this in detail in my book, The Honest Broker (now on sale;-).

Now, the "consistent with" strategy is a double-edged sword because the future is uncertain. It could very well be the case that there is no additional warming over the next decade or longer, or perhaps a cooling. Given such uncertainty, scientists with an eye on the politics of climate change are quick to define pretty much anything that could be observed in the climate system as "consistent with" IPCC predictions in order to maintain their ability to deflect the sort of claims made by Patrick Michaels. For if everything observed is consistent with IPCC predictions, there is no reason to then call into question the scientific basis used to justify policies.

But this strategy runs a real risk of damaging the credibility of the scientific community. It is certainly possible to claim, as some of our commenters have and the folks at RC have, that 20 years of cooling is "consistent with" IPCC predictions, but I can pretty much guarantee that if the world has experienced cooling for 20 years from the late 1990s to the 2000-teens that the political dynamics of climate change and the standing of skeptics will be vastly different than it is today.

Now I am sure that many scientist/activists are just trying to buy some time (e.g., buy offering a wager on cooling, as RC has done), waiting for a strong warming trend to resume. And it very well might, since this is the central prediction of the IPCC. Blogger /activist/scientist Joe Romm gushed with mock enthusiasm when the March temperatures showed a much higher rate of warming than the previous three months. We'll see what sort of announcement he or others put up for the much cooler April temperatures. But all such celebrations, on any side of the debate, do is set the stage for the acceptance of articles like that by Pat Michaels who point out the opposite when it occurs. One way to buy time is to protest, call others names, and muddy the waters. This strategy can work really well when questions of inconsistency take place over a few months and the real world assumes the pattern of behavior found in the central tendency of the IPCC predictions, but if potential inconsistency goes on any longer than this then you start looking like you are protesting too much.

So what is the alternative for those of us who seek action on climate change? I see two options, both predicated on rejecting the linkage between IPCC predictions and current political actions.

1) Recognize that any successful climate policies must be politically robust. This means that they have to make sense to many constituencies for many reasons. Increasing carbon dioxide in the atmosphere will have effects, and these effects are largely judged to be negative over the long term. Whether or not scientists can exactly predict these effects over decades is an open question. But the failure to offer accurate decadal predictions would say nothing about the judgment that continued increasing carbon dioxide is not a good idea. Further, for any climate policies to succeed they must make sense for a lot of reasons -- the economy, trade, development, pork, image, etc. etc. -- science is pretty much lost in the noise. So step one is to reject the premise of claims like that made by Pat Michaels. The tendency among activist climate scientists is instead to accept those claims.

2) The climate community should openly engage the issue of falsification of its predictions. By giving the perception that fallibility is not only acceptable, but expected as part of learning,it would go a long way toward backing off of the overselling of climate science that seems to have taken place. If the IPCC does not have things exactly correct, and the world has been led to believe that they do, then an inevitable loss of credibility might ensue. Those who believe that the IPCC is infallible will of course reject this idea.

Who knows? Maybe warming will resume in May, 2008 at a rapid rate, and continue for years or decades. Then this discussion will be moot. But what if it doesn't?

May 15, 2008

Comparing Distrubutions of Observations and Predictions: A Response to James Annan

James Annan, a climate modeler, has written a post at his blog trying to explain why it is inconceivable that recent observations of global average temperature trends can be considered to be inconsistent with predictions from the models of the IPCC. James has an increasing snarky, angry tone to his comments which I will ignore in favor of the math (and I'd ask those offering comments on our blog to also be respectful, even if that respect is not returned), and in this post I will explain that even using his approach, there remains a quantitative justification for arguing that recent trends are inconsistent with IPCC projections.

James asks:

Are the models consistent with the observations over the last 8 years?

He answers this question using a standard approach to comparing means from two distributions, a test that I have openly questioned its appropriateness in this context. But lets grant James this methodological point for this discussion.

James defines the past 8 years as the past 8 calendar years, 2000-2007, which we will see is a significant decision. As reported to us by his fellow modelers at Real Climate, James presents the distribution of models as having a mean 8-year trend of 0.19 degrees per decade, with a standard deviation of 0.21. So lets also accept this starting point.

In a post on 8-year trends in observational data Real Climate reported the standard deviation of these trends to be 0.19. (Note this is based on NASA data, and I would be happy to use a different value if a good argument can be made to do so.) I calculated the least-squares best fit line for the monthly data 2000-2007 from the UKMET dataset that James pointed to and arrived at 0.10 degrees/C per decade (James gets 0.11).

So lets take a look at how the distribution of 8-year trends in the models [N(0.19, 0.21)] compares to the analogous 8-year trend in the observations [N(0.10, 0.19)]. This is shown in the following graph with the model distribution in dark blue, and the observations in red.

obsVmods1.100-1207.png

Guess what? Using this approach James is absolutely correct when he says that it would be incorrect to claim that the temperatures observed from 2000-2007 are inconsistent with the IPCC AR4 model predictions. In more direct language, any reasonable analysis would conclude that the observed and modeled temperature trends are consistent.

But now lets take a look at two different periods, first the past eight years of available data, so April 2000 to March 2008 (I understand that April 2008 values are just out and the anomaly is something like half the value of April 2000, so making this update would make a small difference).

obsVmods2.400-308.png

You can clearly see that the amount of overlap between the distributions is smaller than in the first figure above. If one wanted to claim that this amount of overlap demonstrates consistency between models and observations I would not disagree. But at the same time, there is also a case to be made that the distributions are inconsistent, as the amount of overlap is not insignificant. There would be an even stronger case to be made for inconsistency using the satellite data, which shows a smaller trend over this same period.

But now lets take a look at the period January 2001 to present, shown below.

obsVmods3.101-308.png

Clearly, there is a strong argument to be made that these distributions are inconsistent with one another (and again, even stronger with the satellite data).

So lets summarize. I have engaged these exercises to approach the question: "What observations of the climate system would be inconsistent with predictions of IPCC AR4?"

1. Using the example of global average temperatures to illustrate how this answer might be approached, I have concluded that it is not "bogus" or "denialist" (as some prominent climate modelers have suggested) to either ask the question or to suggest that there is some valid evidence indicating inconsistency between observations and model predictions.

2. The proper way to approach this question is not clear. With climate models we are not dealing with balls and urns, as in idealized situations of hypothesis testing. Consider that the greater the uncertainty in climate models -- which results from any research that expands the realization space -- will increase the consistency between observations and models, if consistency is simply defined as some part of the distribution of observations overlapping with the distribution of forecasts. Thus, defining a distribution of model predictions simply as being equivalent to the distribution of realizations is problematic, especially if model predictions are expected to have practical value.

3. Some people get very angry when these issues are raised. Readers should see the reactions to my posts as an obvious example of how the politics of climate change are reflected in pressures not to ask these sort of questions.

One solution to this situation would be to ask those who issue climate predictions for the purposes of informing decision makers -- on any time scale -- to clearly explain at the time the prediction is issued what data are being predicted and what values of those data would falsify the prediction. Otherwise, we will find ourselves in a situation where the instinctive response of those issuing the predictions will be to defend their forecasts as being consistent with the observations, no matter what is observed.

Posted on May 15, 2008 09:09 AM View this article | Comments (46)
Posted to Author: Pielke Jr., R. | Climate Change | Prediction and Forecasting | Scientific Assessments

May 14, 2008

Lucia Liljegren on Real Climate's Approach to Falsification of IPCC Predictions

Lucia Liljegren has wonderfully clear post up which explains issues of consistency and inconsistency between models and observations using a simple analogy based on predicting the heights of Swedes.

She writes;

I think a simple example using heights is helps me explain the answer to these questions:
1. Is the mean trend in surface temperature over time predicted by the IPCC consistent with the temperature trends we have been experiencing? (That is: is 2C/century consistent with the trend we’ve seen? )
2. Is the lowest uncertainty bound the IPCC shows the public consistent with the trend in GMST (global mean surface temperature) we have seen since 2001?

I think these questions are important to the public and policy makers. They are the questions people at many climate blogs are asking and they are the questions many voters and likely policy makers would like answered.

I think the answer to both questions is "No, the IPCC predictions are inconsistent with recent data."

Please go to her site and read the entire post.

She concludes her discussion as follows:

The IPCC projections remain falsified. Comparison to data suggest they are biased. The statistical tests accounts for the actual weather noise in data on earth.
The argument that this falsification is somehow inapplicable because the earth data falls inside the full range of possibilities for models is flawed. We know why the full range of climate models is huge: It contains a large amount of "climate model noise" due to models that are individually biased relative to the system of interest: the earth.

It will continue to admit what I have always admitted: When applying hypothesis tests to a confidence limit of 5%, one does expect to be wrong 5% of the time. It is entirely possible that the current falsification fall in the category of 5% incorrect falsifications. If this is so, the “falsified” diagnosis will reverse, and not we won’t see another one anytime soon.

However, for now, the IPCC projections remain falsified, and will do so until the temperatures pick up. Given the current statistical state ( a period when large “type 2″ error is expected) it is quite likely we will soon see “fail to falsify” even if the current falsification is a true one. But if the falsification is a “true” falsification, as is most likely, we will see “falsifications” resume. In that case, the falsification will ultimately stick.

For now, all we can do is watch the temperature trends of the real earth.

Posted on May 14, 2008 02:06 PM View this article | Comments (5)
Posted to Author: Pielke Jr., R. | Climate Change | Prediction and Forecasting | Scientific Assessments

May 12, 2008

How to Make Two Decades of Cooling Consistent with Warming

The folks at Real Climate have produced a very interesting analysis that provides some useful information for the task of framing a falsification exercise on IPCC predictions of global surface temperature changes. The exercise also provides some insight into how this branch of the climate science community defines the concept of consistency between models and observations, and why it is that every observation seems to be, in their eyes, "consistent with" model predictions. This post explains why Real Climate is wrong in their conclusions on falsification and the why it is that two decades of cooling can be defined as "consistent with" predictions of warming.

In their post, RealClimate concludes:

Claims that a negative observed trend over the last 8 years would be inconsistent with the models cannot be supported. Similar claims that the IPCC projection of about 0.2ºC/dec over the next few decades would be falsified with such an observation are equally bogus.

Real Climate defines observations to be "consistent with" the models to mean that an observation, with its corresponding uncertainty range, overlaps with the spread of the entire ensemble of model realizations. This is the exact same definition of "consistent with" that I have criticized here on many occasions. Why? Because it means that the greater the uncertainty in modeling -- that is, the greater the spread in outcomes across model realizations -- the more likely that observations will be “consistent with” the models. More models, more outcomes, greater consistency – but less certainty. It is in this way that pretty much any observation becomes "consistent with" the models.

As we will see below, the assertion by Real Climate that "a negative observed trend over the last 8 years would be inconsistent with the models cannot be supported" is simply wrong. Real Climate is more on the mark when they write:

Over a twenty year period, you would be on stronger ground in arguing that a negative trend would be outside the 95% confidence limits of the expected trend (the one model run in the above ensemble suggests that would only happen ~2% of the time).

Most people seeking to examine the consistency between models and observations would use some sort of probabilistic threshold, like a 95% confidence interval, which would in this case be calculated as a joint probability of observations and models.

So let’s go through the exercise of comparing modeled and observed trends to illustrate why Real Climate is wrong, or more generously, has adopted a definition of "consistent with" that is so broad as to be meaningless in practice.

First the observations. Thanks to Lucia Liljegren we have the observed trends in global surface temperature 2001-present (which slightly less than 8 years), with 95% confidence intervals, for five groups that keep such record. Here is that information she has presented in degrees Celsius per decade:

UKMET -1.3 +/- 1.8
NOAA 0.0 +/- 1.6
RSS -1.5 +/- 2.2
UAH -0.9 +/- 2.8
GISS 0.2 +/- 2.1

Real Climate very usefully presents 8-year trends for 55 model realizations in a figure that is reproduced below. I have annotated the graph by showing the 95% range for the model realizations, which corresponds to excluding the most extreme 3 model realization on either end of the distribution (2.75 to be exact). (I have emailed Gavin Schmidt asking for the data, which would enable a bit more precision. ) The blue horizontal line at the bottom labeled "95% spread across model realizations" shows the 95% range of 8-year trends present across the IPCC model realizations.

I have also annotated the figure to show in purple the 8+ year trends from the five groups that track global surface temperatures, with the 95% range as calculated by Lucia Liljegren. I have presented each of the individual ranges for the 5 groups, and then with a single purple horizontal line the range across the five observational groups.

Quite clearly there is a large portion of the spread in the observations that is not encompassed by the spread in the models. This part of the observations is cooler than the range provided by the models. And this then leads us to the question of how to interpret the lack of complete overlap.

One interpretation, and the one that makes the most sense to me, is that because there is not an overlap between modeled and observed trends at the 95% level (which is fairly obvious from the figure, but could be easily calculated with the original data) then one could properly claim that the surface temperature observations 2001-present fail to demonstrate consistency with the models of IPCC AR4 at the 95% level. They do however show consistency at some lower level of confidence. Taking each observational dataset independently, one would conclude that UKMET, RSS, and UAH are inconsistent with the models, whereas NASA and NOAA are consistent with them, again at a 95% threshold.

Another interpretation, apparently favored by the guys at Real Climate, is that because there is some overlap between the 95% ranges (i.e., overlap between the blue and purple lines), the models and observations are in fact consistent with one another. [UPDATE: Gave Schmidt at RC confirms this interpretation when he writes in response to a question about the possibility of falsifying IPCC predictions: "Sure. Data that falls unambiguously outside it [i.e., the model range]."] But this type of test for consistency is extremely weak. The Figure below takes the 95% spread in the observations and illustrates how far above and below the 95% spread in the models some overlap would allow. If the test of “consistent with” is defined as any overlap between models and observations, then any rate of cooling or warming between -10 deg C/decade and +13.0 dec C/decade could be said to be “consistent with” the model predictions of the IPCC. This is clearly so absurd as to be meaningless.

So when Real Climate concludes that . . .

Claims that a negative observed trend over the last 8 years would be inconsistent with the models cannot be supported

. . . they are simply incorrect by any reasonable definition of consistency based on probabilistic reasoning. Such claims do in fact have ample support.

If they wish to assert than any overlap between uncertainties in observed temperature trends and the spread of model realizations over an 8-year period implies consistency, then they are arguing that any 8-year trend between -10/C and +13/C (per century) would be consistent with the models. This sort of reasoning turns climate model falsification into a rather meaningless exercise. [UPDATE: In the comments, climate modeler James Annan makes exactly this argument, but goes even further: "even if the model and obs ranges didn't overlap at all, they might (just) be consistent".

Of course in practice the tactical response to claims that observations falsify model predictions will be to argue for expanding the range of realizations in the models, and arguing for reducing the range of uncertainties in the observations. This is one reason why debates over the predictions of climate models devolve into philosophical discussions about how to treat uncertainties.

Finally, how then should we interpret Keenlyside et al.? It is, as Real Climate admits, outside the 95% range of the IPCC AR4 models for its prediction of trends to 2015. But wait, Keelyside et al. in fact use one of the models of the IPCC AR4 runs, and thus this fact could be used to argue that the range of possible 20-year trends is actually larger than that presented by the IPCC. If interpreted in this way, then this would get us back to the interesting conclusion that more models, initialized in different ways, actually work to expand the range of possible futures. Thus we should not be surprised to see Real Climate conclude

Similar claims that the IPCC projection of about 0.2ºC/dec over the next few decades would be falsified with such an observation [of "a negative observed trend"] are equally bogus.

And this gentle readers is exactly why I explained in a recent post that Keelyside et al. now means that a two-decade cooling trend (in RC parlance, a “negative observed trend over 20 years”) is now defined as consistent with predictions of warming.

Inconsistent With? One Answer

UPDATE: Real Climate has already dismissed the paper linked below as a failed effort.

Climate Audit provides a pointer to this paper (PDF) by Koutsoyiannis et al. which has the following abstract:

As falsifiability is an essential element of science (Karl Popper), many have disputed the scientific basis of climatic predictions on the grounds that they are not falsifiable or verifiable at present. This critique arises from the argument that we need to wait several decades before we may know how reliable the predictions will be. However, elements of falsifiability already exist, given that many of the climatic model outputs contain time series for past periods. In particular, the models of the IPCC Third Assessment Report have projected future climate starting from 1990; thus, there is an 18‐year period for which comparison of model outputs and reality is possible. In practice, the climatic model outputs are downscaled to finer spatial scales, and conclusions are drawn for the evolution of regional climates and hydrological regimes; thus, it is essential to make such comparisons on regional scales and point basis rather than on global or hemispheric scales. In this study, we have retrieved temperature and precipitation records, at least 100‐year long, from a number of stations worldwide. We have also retrieved a number of climatic model outputs, extracted the time series for the grid points closest to each examined station, and produced a time series for the station location based on best linear estimation. Finally, to assess the reliability of model predictions, we have compared the historical with the model time series using several statistical indicators including long‐term variability, from monthly to overyear (climatic) time scales. Based on these analyses, we discuss the usefulness of climatic model future projections (with emphasis on precipitation) from a hydrological perspective, in relationship to a long‐term uncertainty framework.

The paper provides the following conclusions:

*All examined long records demonstrate large overyear variability (long‐term fluctuations) with no systematic signatures across the different locations/climates.
*GCMs generally reproduce the broad climatic behaviours at different geographical locations and the sequence of wet/dry or warm/cold periods on a mean monthly scale.

*However, model outputs at annual and climatic (30‐year) scales are irrelevant with reality; also, they do not reproduce the natural overyear fluctuation and, generally, underestimate the variance and the Hurst coefficient of the observed series; none of the models proves to be systematically better than the others.

*The huge negative values of coefficients of efficiency at those scales show that model predictions are much poorer that an elementary prediction based on the time average.

*This makes future climate projections not credible.

*The GCM outputs of AR4, as compared to those of TAR, are a regression in terms of the elements of falsifiability they provide, because most of the AR4 scenarios refer only to the future, whereas TAR scenarios also included historical periods.

Posted on May 12, 2008 12:55 AM View this article | Comments (1)
Posted to Author: Pielke Jr., R. | Climate Change | Prediction and Forecasting

May 09, 2008

Real Climate's Bold Bet

The Real Climate guys have offered odds on future temperature changes, which is great because it gives us a sense of their confidence in predictions of future global average temperatures. Unfortunately, RCs foray into laying odds is not as useful as it might be.

The motivation for this bet is the recent Keenlyside et al. paper that has caused a set of mixed reactions among the commenters in the blogosphere. Some commenters here have stridently argued that the predictions in the Keelyside et al. paper are perfectly consistent with predictions of climate models in the IPCC. However, when one such commenter here was asked to show a single IPCC climate model run showing no temperature increase for the 2 decades following the late 1990s he submitted an irrelevant link and disappeared. Others have argued that the Keenlyside et al. projections (and this includes Keenlyside) are inconsistent with the IPCC predictions. Real Climate apparently falls into this latter camp.

The Real Climate Bet (and there is also one for a later period) is that the period 1994-2004 will have a higher average temperature than the period 2000-2010. Since the periods have in common 2000-2004, we can throw those out as irrelevant. Thus, the bet is really about whether the period 1994-1998 will be warmer than the period 2005-2010. And since we know the temperatures for 2005 to present, the bet is really about what will happen in 2009 and 2010. (Using UKMET temps here.)

It is strange to see the Real Climate guys wagering on 2-year climate trends when they already taught us a lesson that 8 years is far to short for trends to be meaningful. But perhaps there is some other reason why they offer this bet. That reason is that they are playing with a stacked deck, which is what you do when looking for suckers. The following figure shows why.

For the Real Climate guys to lose the bet global average temperatures for 2009 and 2010 would have to fall by about 0.30 from the period 2005-present (and I've assumed Jan-Mar as the 2008 value, 2008 obviously could wind up higher or lower). Real Climate has boldly offered 50-50 odds that this will happen. This is a bit like giving 50-50 odds that Wigan will come back from a 3-0 halftime deficit to Manchester United. Who would take that bet?

Another interpretation of the odds provided by RC is that they actually believe that there is a 50% chance that global temperatures will decrease by more than 0.30 over the next few years. Since I don't think they actually believe that, it is safe to conclude that they've offered a suckers bet. Too bad. When Real Climate wants to offer a 50-50 bet in which the bettor gets to pick which side to take in the bet (i.e., the definition of 50-50) then we'll know that they are serious.

Posted on May 9, 2008 08:23 AM View this article | Comments (24)
Posted to Author: Pielke Jr., R. | Climate Change | Prediction and Forecasting | Risk & Uncertainty

May 08, 2008

Consistent With, Again

On NPR's Fresh Air earlier this week, Al Gore suggests that Typhoon Nargis, which may have killed 100,000 people in Myanmar, is linked to greenhouse gas emissions, or does he? He said "we’re seeing consequences that scientists have long predicted might be associated with continued global warming."

What could he have meant? If you ask me, I'd say that the "consistent with" chronicles continue . . .

PS. Those wanting to do something positive in the face of this tragedy might visit this site.

Posted on May 8, 2008 02:16 PM View this article | Comments (2)
Posted to Author: Pielke Jr., R. | Climate Change | Disasters | Science + Politics

Teats on a Bull

Here is a very thoughtful comment sent in by email on the ""consistent with chronicles". I haven't identified the author, since he didn't ask me to post it. But it is worth a read about how climate science is received by one rancher in West Tennessee. I appreciate the feedback.

I am neither an academic nor a scientist. I raise cattle in West Tennessee. I came across your ruminations on the uses and meaning (or lack thereof) of the expression "consistent with" in environmental debates. I enjoyed it very much. You make some very valid, interesting, and to your critics irritating points.
You hear "consistent with" employed in other circumstances as well, as for example when a prosecuting attorney says certain evidence is "consistent with" his or her theory of who committed a crime. However a good defense attorney will almost surely point out that the evidence in question is "consistent with" other explanations as well. Thus, at least in legal dealings, the "consistent with" argument doesn't get one very far.

Which brings me to my point. You're absolutely right to ask what kinds of evidence would be inconsistent with environmental theories, for just the reasons you outline, but of equal or perhaps greater importance is the question "With what other theories or explanations is the same evidence consistent?" It is not so terribly unusual for facts or evidence to be consistent with multiple theories, even ones that contradict one another. I'm clearly not qualified to judge, but could the cited evidence also be "consistent with" environmental theories involving sunspot activity, the Gulf Stream, el Nino, or lord knows what else?

There's another problem I see with the "consistent with" construction: it never addresses the issue of probability. One sees this frequently with the use of "possible." For many folks the claim that something, no matter how implausible, is "possible" is enough to end a discussion. The mere theoretical possibility of something is to their minds proof of its reality. And the truth is it's virtually impossible to prove, especially to such people, that something is impossible. The best one can do is assess probabilities. However, to the true believer, even the highest statistical improbability carries little if any weight. The same, I think, is true for those who offer the "consistent with" argument. Although to their minds they may be equivalent, "consistent with" is not the same thing as "equal to," just as "possible" is not the same thing as "actual."

My personal feeling is that "consistent with" is a hedge term that has about as much meaning, and carries about as much weight, as what we here in West Tennessee call a WAG, or wild ass guess. The number of things a thing can be "consistent with" is so large as to rob the expression of meaning, or communicative value. If my veterinarian looked at one of my cows and informed me that her swollen belly was "consistent with" her being pregnant, I'm not sure I'd find that of much value, as it's also "consistent with" a number of other things, some benign, some fatal.

"Consistent with" doesn't help me make decisions on the farm. With regards to the much more vast and consequential issue of global weather predictions, "consistent with" is to me about as useful as teats on a bull.

Again, you produced a fine article and I enjoyed reading it. Keep pushing environmentalist towards honesty and clarity. A very great deal is at stake, as I'm sure you know.

Iain Murray on Climate Policy

Over at his blog Iain Murray, who is with the Competitive Enterprise Institute, has a thoughtful response to my initial post on elements of any successful approach to climate change. I won't try to summarize Iain's lengthy post, so go there read it and come back. (Thanks to BP for the pointer.)

Here are some very quick responses of my own.

1. I appreciate Iain's efforts to "propose an alternative framework that may be more appealing to conservative policy-makers." In the U.S there is a wide gap between Democrats and Republicans on many aspects of climate policy. If this gap is to close in the form of shared agreement on action, it will result from having an open discussion of policies resulting in compromises, and not by the finger-pointing, name calling, and derision that so often accompanies political debates on climate change. As Walter Lippmann once wrote, the goal of politics is not to get people to think alike, but to get people who think differently to act alike.

2. On adaptation Iain and I see to agree more than disagree. I recognize that the concept of "sustainable development" carries with it much symbolic baggage and people read into the concept an awful lot. I don't see a Malthusian perspective in the concept, far from it. I actually see that technological progress that eliminates limits and opens possibilities as key to sustainable development. There is much more to say, but on issues of technology and trade, i see no real significant disagreements here.

3. Iain is correct in pointing out the real costs associated with making carbon-based energy more expensive. This is the main reason that I see that its political prospects are seriously limited. But even so, Iain probably recognizes that what he calls "costs" are viewed by many people as "benefits". That is, many people would like energy to be more pricier, even if it results in costs for some other people . For some, they focus on the non-market costs of carbon-based energy and thus evaluate the costs/benefits with some implicit valuation of the intangibles, but others simply prefer the outcomes associated with pricier energy. I have no expectation that people with vastly different values will come to agreement on costs and benefits associated with pricing carbon, hence, I see its prospects as limited in any case.

4. Iain likes the idea of making carbon-free energy "more affordable" but has some different recommendations than I do on how it might be done. Great. I don't think that anyone has a magic bullet solution, so agreement on the goal ought to be a enormous first step in its achievement. This is one reason why I listed a laundry list of options. I would hope that Iain would agree that the world really hasn't set forth in this direction in any real seriousness, at least not as compared to the intensity of action focused on pricing carbon. But we seem to agree on the goals here.

Iain has some more specific actions described at his blog that are worth a read. If anyone else wants to share their reactions to this discussion they are welcome to do so in the comments or as a guest blog.

May 06, 2008

Elements of Any Successful Approach to Climate Change

This post summarizes, in capsule form, what I believe to be the necessary elements of any successful suite of policies focused on climate mitigation and adaptation. This post is short, and necessarily incomplete with insufficient detail, nonetheless, its purpose is to set the stage for future, in depth discussions of each element discussed below. The elements discussed below are meant to occur in parallel. All are necessary, none by itself sufficient. I welcome comments, critique, and questions.

1. Adaptation

Whatever the world does on mitigation, adaptation will be necessary. And by adaptation I don’t simply mean adaptation to the marginal impacts of human-caused climate change, as presented under the Framework Convention on Climate Change. I mean adaptation to climate, and as such, a concept much more closely related to the original notion of sustainable development. Adaptation is therefore core to any approach to

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