Thinner than Normal Arctic Sea Ice Poised for a Rapid Decline in 2010

The National Snow and Ice Data Center (NSIDC) announced today that Arctic sea ice reached a seasonal maximum coverage on 31 March, with the monthly average well below average levels during the final decades of the 20^th century. As rising atmospheric greenhouse gases have driven up temperatures in the region and globally, the monthly average extent for March has declined an average of 2.6% between 1978 and 2010 (see figure below). 

Source: National Snow and Ice Data Center

Sea ice extent shrinks during the melt season (usually beginning in March and extending into September) and expands during the growth period (usually from September into March).  The end of the growth period for Arctic sea ice came a few weeks late this year, allowing the formation of additional new ice and pushing the overall extent close to the 1979-2000 average near the end of the month (see figure below).

Above: "The graph above shows daily sea ice extent as of April 4, 2010. The solid light blue line indicates 2010; green shows 2007; dark blue indicates 1999, the year with the previous latest maximum extent, which occurred on March 29, 1999; and solid gray indicates average extent from 1979 to 2000. The gray area around the average line shows the two standard deviation range of the data. Sea Ice Index data."  Caption and Image from National Snow and Ice Data Center

 

Climate change contrarians, exploited the ephemeral surge in new ice to misleadingly suggest that the Arctic was back to normal and that climate change concerns were overblown.

 

But the data released today by the NSIDC indicate that conditions are anything but normal in the region.  The average ice extent for March 2010 was 250,000 square miles (nearly the size of Texas) below the 1979-2000 average for March.  More importantly, the ice is becoming thinner; there is much less thick multi-year ice in the region now than during the 1980s and 1990s – and much more first-year ice that is thin and more likely to melt away during the melt season.  See figure below; and this illustration and this figure from Climate Central.

Above: Map of Global Surface Temperature Anomalies, Winter 2009-2010.  Areas that were anomalously cool run from light blue to purple.  Areas that were anomalously warm range from light yellow to deep red.  Source: NASA GISS.

Above: "This map of air temperature anomalies for March 2010, at the 925 millibar level (roughly 1,000 meters or 3,000 feet above the surface), shows warmer than usual temperatures over most of the Arctic Ocean, but colder than usual temperatures in the Bering and Barents seas, where sea ice extent is above normal. Areas in orange and red correspond to positive (warm) anomalies. Areas in blue and purple correspond to negative (cool) anomalies. Source for caption: NSIDC."  Source for image: NSIDC, courtesy NOAA/ESRL Physical Sciences Division.

Online Resources:

• Cold snap causes late-season growth spurt.  National Snow and Ice Data Center, 6 April 2010.
• Arctic Sea Ice is Shrinking, Despite Contrarian Claims.  Press release (6 April 2010) from the Union of Concerned Scientists.
• Climate Central:
  • Arctic Changes: The Big Picture: Three minute video
  • Arctic Changes graphics collection
• Dramatic Ice Loss Spreads to Northwest Coast of Greenland.  WWF Climate Blog, 23 March 2010.
• NOAA: Decline of Arctic Sea Ice is Affecting Fall and Winter in U.S. and Elsewhere .  WWF Climate Blog, 20 March 2010.
• Vast Reservoirs of Methane in Arctic Seafloor Are Leaking Large Amounts of Powerful Greenhouse Gas to Atmosphere .  WWF  Climate Blog, 4 March 2010.
• Warm Ocean Waters are Speeding Greenland Glacier Melt. Climate blog posting, 21 February 2010. 
• Looking for Above Normal Temperatures? They are in the Arctic.  Climate blog posting, 5 January 2010. 
• Arctic Climate Impact Science - an update since ACIA.  Published in April 2008 by WWF International Arctic Programme.
• Arctic Warming Threatens Future Of The Planet -  Press release (16 December 2008) from WWF.  
• 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.