The Arctic Snowball Effect


It's been a bad summer up north:

The Arctic sea ice extent [Sunday] fell below its previous record low and is currently losing frozen sea at the rate of ~29,000 square miles (~75,000 square kilometers) a day. That's equivalent to an area the size of South Carolina every 24 hours. … Note that this year's record low was set more than three weeks earlier than the 2007 record. And summer isn't over yet. There's more melting to come.

Michael Lemonick explains how all that ice isn't just ice; it's part of our defense against the sun – and its loss accelerates climate change:

Arctic ice, whether on land or on the sea, is a powerful reflector that bounces a lot of sunlight back into space rather than letting it warm the Earth. When that ice melts, it exposes the darker ground or water underneath, turning the region into an energy absorber rather than a reflector. Sea ice is especially vulnerable to melting, and over the past 30 years or so there’s been a downward trend in sea ice coverage in summer. The result is a feedback loop that accelerates global warming, with melting ice leading to more warming of the water below leading to more melting. The Arctic is warming at nearly twice the rate of the rest of the globe, largely due to those feedback loops. In addition, recent research shows that the loss of sea ice cover may be contributing to extreme weather events throughout the Northern Hemisphere, and may be partly responsible for major cold air outbreaks and paralyzing snowstorms in the northeastern U.S. and western Europe during the past few years.

(Image: Visualization showing the extent of Arctic sea ice on Aug. 26, 2012. By Scientific Visualization Studio, NASA Goddard Space Flight Center)