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A nearly ice-free Arctic Ocean in the summer may happen three times sooner than scientists have estimated. New research says the Arctic might lose most of its ice cover in summer in as few as 30 years instead of the end of the century.

The amount of the Arctic Ocean covered by ice at the end of summer by then could be only about 1 million square kilometers, or about 620,000 square miles. That’s compared to today’s ice extent of 4.6 million square kilometers, or 2.8 million square miles. So much more open water could be a boon for shipping and for extracting minerals and oil from the seabed, but it raises the question of ecosystem upheaval.

While the Intergovernmental Panel on Climate Change in 2007 assessed what might happen in the Arctic in the future based on results from more than a dozen global climate models, two researchers reasoned that dramatic declines in the extent of ice at the end of summer in 2007 and 2008 called for a different approach.

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An article published this week in Nature Geoscience shows that black carbon is responsible for 50 percent,  Arctic warming from 1890 to 2007. The paper by Drew Shindell of the NASA Goddard Institute for Space (GISS) and Greg Faluvegi of Columbia University also notes that most of the Arctic warming occurred from 1976 to 2007.

The study is the first to quantify the Arctic’s sensitivity to black carbon emissions from various latitudes, and concludes that the Arctic responds strongly to black carbon emissions from the Northern Hemisphere mid-latitudes, where the emissions and the forcing are greatest.

Black carbon is an aerosol produced from the incomplete combustion of fossil fuels and biomass and is estimated to be the second or third largest contributor to climate change. Its emissions cause damage in two ways: while in the atmosphere, the dark particulates absorb sunlight and emit it as heat; when it falls back to earth it can darken snow and ice, reducing their reflectivity and accelerating melting. Arctic warming is more than twice the observed global average surface warming  above pre-industrial levels. According to another study published by Lenton, et al. in the Proceedings of the National Academy of Sciences last year, this increased warming may soon lead to the disappearance of the Arctic summer ice, which would in turn accelerate Arctic warming by exposing darker heat-absorbing water now covered by heat reflecting ice. This would also increase the risk of releasing methane and other greenhouse gases from permafrost and from methane hydrates in the ocean, which could lead to a runaway feedback process.

The mission of the Institute for Governance & Sustainable Development is to promote just and sustainable societies and to protect the environment by advancing the understanding, development and implementation of effective, accountable and democratic systems of governance for sustainable development. The Institute brings together professionals from around the world who are committed to strengthening environmental law and institutions to promote sustainable development. For more information on the Institute, please visit http://igsd.org/.

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