As Sea Ice Reaches Annual Minimum, Impacts of Arctic Warming Grow

[Note from author Nick Sundt: On 17 September 2009, the day after this posting, the National Snow and Ice Data Center issued a detailed statement, Arctic Sea Ice Reaches Annual Minimum Extent, with additional data and graphics.  Check it out.]
The extent of sea ice in the Arctic appears to have reached its annual minimum on 12 September 2009 – the third lowest on record (see figure from the National Snow and Ice Data Center). Since summer sea ice extent plunged to a record low in 2007, it has not recovered to previous levels (2008 had the second lowest sea-ice extent).  Furthermore, there has been a recent and dramatic decline in the volume of sea ice, i.e. the ice is getting thinner. 
As climate change triggers a sharp decline in sea ice, there are serious consequences within the Arctic region. Among recent (September) developments:
** Record high temperatures. Researchers report in Science (4 September) that temperatures in the Arctic were the warmest in 2,000 years – and would otherwise be cooling were in not for rapidly increasing atmospheric concentrations of greenhouse gases.
** Major ecological impacts reported. A group of scientists report in the journal Science on 11 September that climate change has “severely perturbed” Arctic ecosystems and that the “rapid changes may be a bellwether of changes to come at lower latitudes.” They report that some of the most rapid ecological changes are among species that “depend on ice for foraging, reproduction, and predator avoidance,” including the ivory gull, Pacific walrus, ringed seal, hooded seal, narwhal, and polar bear.
** Increased navigability of Arctic waters. Two German commercial vessels completed the first commercial transit of the Northeast Passage, travelling from South Korea and arriving in Yamburg, Siberia, on 12 September. From there, they will proceed to Rotterdam.
** Some recent examples of sea-ice related impacts on wildlife in Alaska:
**** Walruses. As in 2007, Walruses have gathered along the northwest coast of Alaska as sea ice retreated beyond the continental shelf. When the edge of the ice recedes beyond the edge of the shelf, it is over water too deep for the Walrus to feed in; they are forced to feed from land rather than from the sea ice. On 8 September, the Fish and Wildlife Service (FWS) announced a review of the walrus’ status, to determine whether it should be added to the list of threatened and endangered species under the Endangered Species Act. According to the FWS, the decision was based “in part, upon projected changes in sea ice habitats associated with climate change.”
**** Pacific brants. The USGS reported on 9 September that the winter distribution of the Pacific brant, a goose that nests mostly in Alaska, is shifting northward – with a larger part of the population wintering in Alaska instead of areas to the south. According to the USGS, a reduction of coastal sea ice is one of the contributing factors. With less sea ice, the geese have easier access to their primary food during the non-breeding season: eelgrass.
Arctic climate change has serious consequences outside of the Arctic. It is:
** affecting atmospheric circulation in the Northern Hemisphere, with serious implications for precipitation and freshwater resources across the U.S. and elsewhere in the Northern Hemisphere.
** affecting the most important source of fish (the waters around Alaska) consumed in America
** triggering “feedbacks” that accelerate regional and global climate change
** affecting ocean circulation
** accelerating sea level rise
** affecting global maritime commerce and national security.
These impacts will increase as climate change accelerates.
Two Responses are Essential. The alarming consequences of actual and potential climate change in the Arctic highlight the need for two essential steps: (1) slow climate change by reducing emissions, (2) prepare for the rapidly emerging consequences of climate change. Legislation that addresses those two challenges must be passed by the Senate and sent by Congress to the President this year. Here is what you can do to help make that happen.
** Arctic Climate Feedbacks: Global Implications (PDF, 10.3 MB). Report edited by Martin Sommerkorn & Susan Joy Hassol and published by the WWF International Arctic Programme. This report provides a comprehensive look at how human-induced climate change is affected the Arctic earlier than expected. This assessment of the most recent science shows that numerous arctic climate feedbacks will make climate change more severe than indicated by other recent projections, including those of the Intergovernmental Panel on Climate Change Fourth Assessment report (IPCC 2007). This report outlines how climate change is already destabilizing important arctic systems and the impacts of these changes on the Earth’s climate system. See also the press release: Warming In The Arctic Could Have Far-Reaching Consequences For U.S. And Planet (September 02, 2009)
** WWF International Arctic Programme.
National Snow and Ice Data Center:
** Latest Arctic Sea Ice News and Analysis
** National Snow and Ice Data Center, Arctic Amplification (August 2009)
** Frequently Asked Questions about Arctic sea ice
Arctic Regional Ocean Observing System (Arctic ROOS): Observations
Kaufman, D. S., D. P. Schneider, N. P. McKay, et al. 2009. “Recent warming reverses long-term Arctic cooling.” Science, p. 1236-1239. See also press release, Arctic at warmest levels in 2,000 years or more.
Eric Post, Mads C. Forchhammer, M. Syndonia Bret-Harte, Terry V. Callaghan, Torben R. Christensen, Bo Elberling, Anthony D. Fox, Olivier Gilg, David S. Hik, Toke T. Høye, Rolf A. Ims, Erik Jeppesen, David R. Klein, Jesper Madsen, A. David McGuire, Søren Rysgaard, Daniel E. Schindler, Ian Stirling, Mikkel P. Tamstorf, Nicholas J.C. Tyler, Rene van der Wal, Jeffrey Welker, Philip A. Wookey, Niels Martin Schmidt, and Peter Aastrup, 2009. “Ecological Dynamics Across the Arctic Associated with Recent Climate Change.” Science 11 September 2009: 1355-1358. See press release, UH: The change in Arctic nature foreshadows the global environment of the future, from University of Helsinki, 11 Sep 2009.
Opting Out of Migration: As Climate Warms, Arctic-Nesting Geese Elect to Winter in Alaska Instead of Mexico. Press release from USGS, 9 Sep 2009.
Protection of Pacific Walrus Under the Endangered Species Act May Be Warranted, U.S. Fish and Wildlife Service Finds. Press release (8 Sep 2009) from U.S. Fish and Wildlife Service.
3rd Symposium on the Impacts of Ice-Diminishing Arctic on Naval and Maritime Operations. Held from 9-11 June 2009 in Annapolis, Maryland.
Kwok, R., G. F. Cunningham, M. Wensnahan, I. Rigor, H. J. Zwally, and D. Yi (7 July 2009), Thinning and volume loss of the Arctic Ocean sea ice cover: 2003–2008, Journal of Geophysical Research.

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