The Arctic continues its rapid change as a result of increasing temperatures.
The summer (September) Arctic sea ice extent continues to decline by slightly over 11 percent per decade; although the decline is slower, winter sea ice in the region is also on a clear downward trend.
According to the National Snow and Ice Data Center (NSIDC), ice extent in May was the third lowest for that month since satellite records began in 1979; in June, it was the second lowest for that month, behind only 2010. At the same time, data from the University of Washington's Polar Science Center underlines that the ice that remains is, on average, thinner than before.
The net result is a growing sense that the Arctic Ocean will be free of sea ice in the summer earlier than all but the most pessimistic predictions had previously forecast.
"There will be ups and downs, but we are on track to see an ice-free summer by 2030. It is an overall downward spiral," NSIDC director Mark Serreze told The Guardian this week.
BLOG: Loss of Sea Ice Poses Mercury Risk
Arctic Ocean sea ice is but one of the rapid and profound changes occurring in the region's cryosphere (sea and ice cover), as pointed out in a recent report, Snow, Water, Ice and Permafrost in the Arctic (SWIPA) Assessment, published by the Arctic Monitoring and Assessment Program (AMAP):
The observed changes in sea ice on the Arctic Ocean, in the mass of the Greenland Ice Sheet and Arctic ice caps and glaciers over the past ten years are dramatic and represent an obvious departure from the long‐term patterns. The warming of the Arctic, due to climate change, has been twice as high as the world average since 1980. Surface air temperatures in the Arctic since 2005 have been higher than for any five‐ year period since measurements began around 1880. Arctic summer temperatures have been higher in the past few decades than at any time in the past 2000 years.
Big Pics: Rapid Arctic Sea Ice Melt from Above
Although the long-term driver behind these declines is an increase in temperature as a result of the burning of fossil fuels, they are exacerbated by interactions with natural phenomena. For example, when summer sea ice extent plummeted to its record lowest extent in 2007, it was a result, not just of higher temperatures, but of a high pressure system that allowed sunlight to beat down on the ice through clear blue skies and warm winds that drove ice from the Siberian shore. This is reinforced by an upcoming paper in the Journal of Geophysical Research, in which James Screen of the University of Melbourne and colleagues report that summer Arctic sea ice extent can be heavily influenced by spring weather farther south: years in which ice loss is particularly dramatic tend to be characterized, as in 2007, by calm, sunny conditions and an absence of storm systems tracking north into the Arctic from Eurasia.
Speaking last month at the 4th Symposium on the Impacts of an Ice-Diminishing Arctic on Naval and Maritime Operations in Washington, D.C., Jim Overland of NOAA's Pacific Marine Environmental Laboratory pointed to the emergence of several "surprises" - trends in the Arctic that are even more extreme than most models and predictions. For example we have seen a 42 percent loss in multiyear sea ice in the Arctic between January 2004 and 2008, as well as increases in Greenland ice melt since 1979, with the largest loss of mass occurring in 2010.
Overland warned that increases in carbon dioxide combined with naturally-occurring warm climate patterns, plus feedbacks from the ice and the ocean, are creating a new climate state in the Arctic - a journey that is, in his words, a "one way trip."
Photograph by Andy Mahoney/NSIDC
Tags: Climate Change, Global Warming, Meteorology
comments ( )