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Photo of Koni SteffenDr. Konrad Steffen, Director for the Cooperative Institute for Research in Environmental Sciences (CIRES), will give a talk on "Changes in the Arctic Ice Cover" on Thursday, February 26, 2009. The talk will be from 2:00 - 3:00 pm in the CSTPR Conference Room.

The talk is free and open to the public and will be held at the Center for Science and Technology Policy Research's conference room. Click here for directions.

Abstract: Air temperatures on the Greenland ice sheet have increased by 4 deg. C since 1991. The ice sheet melt area increased by 30% for the western part between 1979-2006, with record melt years in 1987, 1991, 1998, 2002, 2005, and possibly the most extreme melt year in 2007. The increasing trend in the total area of melting bare ice is unmistakable at 13% per year, significant at a probability of 0.99. Hence, the bare ice region, the wet snow region, and the equilibrium line altitude have moved further inland and resulting in increased melt water flux towards the coast. Warm and extended air temperatures are to blame for 1.5 m water equivalent surface reduction at the long-term equilibrium line altitude, 1100 m elevation at 70 deg. N during summer 2007. Increase in ice velocity in the ablation region and the concurrent increase in melt water suggests that water penetrates to great depth through moulins and cracks, lubricating the bottom of the ice sheet. New insight was gained of subsurface hydrologic channels and cavities using new instrumentation and a video system during the melt peak in August 2007. Volume and geometry of a 100 m deep moulin were mapped with a rotating laser, and photographs with digital cameras. Sub-glacial hydrologic channels were investigated and filmed using a tethered, autonomous system, several hundred meters into the ice. These new results will be discussed in view of the rapid increase in melt area and mass loss of the Greenland ice sheet due to increasing air temperatures.

Biography: Isolated and frozen for much of the year, a lonely research station called Swiss Camp sits on the Greenland ice sheet, one of the largest bodies of ice on the planet. For many summers, Dr. Konrad Steffen and his team of scientists have trekked to Swiss Camp to study the ice sheet. His research has yielded unexpected, alarming results: ice melt is occurring at a rate of 13% per year, and the ice is not replenished in winter as it had been for millennia. Dr. Steffen’s research indicates that the rapid increase in melt area and mass loss of the Greenland ice sheet is due to increasing air temperatures. Dr. Steffen is a professor of geography at the University of Colorado teaching climatology and remote sensing. He has led field expeditions to the Greenland ice sheet and other Arctic regions for the past 33 years to measure the dynamic response of ice masses under a warming climate. He is the director of the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado, Boulder. His research has been studied by international scientists, experts and governmental officials and featured on television, radio, and in many scientific journals and popular magazines.

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