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Disappearing Polar Bears and Permafrost: Is a Global Warming Tipping Point Embedded in the Ice?

Date: Wednesday, October 17, 2007 Time: 12:00 AM Location: Washington D.C.

Opening Statement By Chairman Brad Miller

This Committee held three hearings on the 2007 report of the Intergovernmental Panel on Climate Change (IPCC), one of last week’s winners of the Nobel Prize for Peace. The report of the working group on impact, adaptation and vulnerability stated that the rapid climate changes occurring in the earth’s polar regions would have “cascading effects on key regional bio-physical systems and cause global climatic feedbacks.” (“Climate Change 2007: Impacts, Adaptation and Vulnerability,” Chapter 15, p. 655, Fourth Assessment Report of the IPCC.)

The report described the polar regions as geopolitically and economically important and extremely vulnerable to current and projected climate change. And the report said the polar regions had the greatest potential to affect global climate change and thus human populations and biodiversity. Id.

In the past twelve months, there have been two remarkable stories related to the Arctic that suggest that those climate changes may be happening even faster than predicted and with significant negative consequences. Earlier this month, the National Snow and Ice Data Center at the University of Colorado reported that the Arctic sea ice cover in the summer of 2007 had fallen to its lowest point since 1979. Sea ice coverage was 39 percent below the long-term average from 1979 to 2000, and perhaps half the sea ice coverage of the 1950s.

According to the Center, Arctic sea ice has long been recognized as a sensitive climate indicator. When global temperatures rise, the sea ice cover shrinks. And global temperatures in the Arctic have risen four degrees Fahrenheit since 1950. The lead scientist for the Snow and Ice Center warned that, “The sea ice cover is in a downward spiral and may have passed the point of no return. As the years go by, we are losing more and more ice in summer and growing back less and less ice in winter. We may well see an ice-free Arctic Ocean in our lifetimes. The implications for global climate, as well as Arctic animals and people, are disturbing.”

There has not been an ice-free summer in the Arctic in a million years.

Not surprisingly, the U.S. Geological Survey in September issued a report projecting that, based on projected sea ice melts, two-thirds of the world’s polar bears will be gone by 2050. The USGS projects that in three of the four ice eco-regions of the Arctic, it is most likely that the bears will be extinct by 2100. In the fourth region, the modeling projects almost even odds that the bears will be somewhere between having a small population to being extinct, but a small population may not be enough to sustain the species.

Polar bears are adapted to hunting from sea ice. They hunt primarily ringed seals and, to a lesser degree, bearded seals. Less sea ice means less habitat. The USGS analysis relied on models to project polar bear populations that are more conservative about the melting of sea ice than the steeper decline being observed in the Arctic. Further, the modeling did not consider the consequences of permafrost melt and other environmental influences that would apply if the world begins to extract more resources from the Arctic, and if a Northwest Passage becomes a reliable shipping route. Those activities would have an obvious negative effect on any remaining polar bear population.

Diminishing bears and sea ice are only the most widely reported aspects of a warming Arctic. Global climate scientists worry about “tipping points”—atmospheric processes that could lead to rapid and irreversible changes in the overall global climate or in sea level rise. The Arctic contains several potential sources of a tipping-point in the boreal forests, the albedo effects of melting ice and -- one of the most frightening -- carbon and methane release from melting permafrost.

Again, the polar regions – the Arctic and the Antarctic – have the greatest potential of any region to affect global climate everywhere. The impacts of global warming will be greater in the polar region, and those impacts will also produce feedback effects that have globally significant consequences. First, ice and snow reflect solar radiation in a process known as “albedo.” It helps keep the Arctic cold and the earth cooler. When there is less ice and less snow, exposed soil and water absorb solar radiation instead of reflecting it, and more solar radiation and warmth reaches land and stays in the atmosphere. It’s a cycle: Ice melts and snow cover is reduced, resulting in less reflectivity and more warming, resulting in more ice melting and reduction of snow cover.

Second, because of higher temperatures in the Arctic, the permafrost beneath large sections of Europe, Russia, Alaska and Canada is also beginning to melt. There are estimated to be almost 1,000 gigatons of carbon trapped in the Arctic permafrost. A gigaton is a billion tons. Human use of fossil fuels currently emits approximately seven gigatons of carbon annually. In 2005, scientists at the Snow and Ice Data Center projected 50 percent of the topmost layer of permafrost would melt by 2050 and as much as 90 percent by 2100. If that happens, the resulting releases of C02 and methane could have a warming effect on our climate that defies imagination. Another potential source for carbon release rests in the boreal forests of the North. Warmer weather has made them vulnerable to insect pests, and drought has resulted in the largest forest fire ever witnessed on Alaska’s Northern Slope. It may also have damaged the permafrost.

None of the models used in the IPCC projections of the impact of global warming took into account the potential release of these gigatons of carbon. A vast area of the world that has been a net carbon sink could become a carbon dioxide and methane producer that would dwarf the production of carbon dioxide and methane now resulting from human activities. As Dr. Ted Schuur wrote in Science magazine in June of 2006, “Factors inducing high-latitude climate warming should be mitigated to minimize the risk of a potentially large carbon release that would further increase global warming.”

Rapid Arctic ice and permafrost melt are the kind of events with “cascading effects” that tip the planet’s climate into an uncontrollable cycle of warming. The result could be an acceleration of the melting of the ice sheets in Greenland, inundating coastal communities and the devastating the world economy.

For twenty years we have heard warnings from scientists—first in a forum here held by Mr. Gore, an alumnus of this committee.

Now we are seeing the consequences of global warming in the endangering of polar bears, in the eroding infrastructure of the Arctic and in the melting sea ice.

Dr. James Hansen of NASA said a year ago that we have ten years to act. If he is right, we have nine years left to put this country, and the world, on a path to reducing aggressively our carbon emissions. We certainly can do it, and probably at a relatively modest cost, if we have the will.

Some dismiss the threat of global warming as gloom and doom, and proclaim themselves to be sunny optimists who believe things will turn out all right. Willfully ignoring dangers and turning a blind eye to all evidence that there are problems that need our urgent attention is not optimism, it is folly. It is optimism to believe that we can prove equal to the challenges before us, however daunting. But we better get about it.



1 - Dr. Richard Alley
Evan Pugh Professor of Geosciences, Department of Geosciences Pennsylvania State University Pennsylvania State University
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2 - Dr. Glenn Juday
Professor, School of Natural Resources and Agricultural Sciences University of Alaska University of Alaska
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3 - Dr. Sue Haseltine
Associate Director for Biology U.S. Geological Survey Department of the Interior U.S. Geological Survey Department of the Interior
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4 - Ms. Kassie R. Siegel
Director, Climate, Air and Energy Program Center for Biological Diversity Center for Biological Diversity
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