In thirty years, the sea ice cover in the Arctic summer could be melted down to a few remnants north of Greenland and Canada. Image: University of Washington / NOAA
Read out Already in thirty years, the ice cover of the Arctic could have almost completely withdrawn in the summer. The American researcher feared James Overland of the National Oceanic and Atmospheric Administration (NOAA) in Seattle. So far, researchers have assumed that climate change will not lead to ice-free Arctic summers until the end of this century. An interaction of natural climatic fluctuations and greenhouse gas-induced high temperatures are the main cause of the rapid transformation of the Arctic. In their calculations, the researchers took into account the extreme loss of sea ice in September 2008 and September 2007. With these data, they fed six different climate models. In particular, three of these computer models are intended to reproduce in detail the complex physical interactions between sea ice and its surroundings. As early as 2037, the Arctic could be ice-free in summer, the researchers found. "The Arctic changes faster than expected, " comments Overland.

The summer ice is said to dwindle from the current 4.6 million square kilometers of area to one million square kilometers? always referring to the September of a year. North of Canada and Greenland it would remain in parts, while sea ice cover is decreasing mainly between Alaska and Russia.

Researchers often refer to the Arctic as a cold store on Earth: the ice-covered region cools the planet by throwing the sun's rays back into space. If the sea ice retreats, the open water absorbs the heat radiation. This heats the Arctic Ocean and air layers and could further fuel climate change.

James Overland (National Oceanic and Atmospheric Administration, Seattle) et al: Geophysical Research Letters (DOI: 10.1029 / 2009GL037820). ddp / science.de? Martin Schäfer advertisement

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