The annual melting of Arctic sea ice is trending toward another record-low.
While it's still too early to say whether the 2009 melt will exceed the record 2007 melt -- the annual low-point isn't reached until September -- the trend line for 2009 for the first time has dipped below 2007, according to the latest data from the National Snow and Ice Data Center.
Another record would be startling, but not surprising. Just 30% of the sea ice in the Arctic at the height of the winter freeze was thicker multi-year ice, leaving 70% susceptible to rapid melting. The amount of ice in the Arctic as of February 2009 -- the height of the annual freeze -- was the lowest on record. Most arctic scientists now say they expect an ice-free Arctic in summer within the next three decades -- far ahead of the projections in the last comprehensive United Nations report on global warming.
The melting of Arctic sea ice is one of the clearest signals of global warming, and a leading indicator of what is to come. The melting is also an example -- one of many -- of a positive feedback loop that scientists expect will accelerate global warming: As sea ice melts, the darker water that is exposed absorbs more of the sun's energy, which leads to warmer waters and more melting ice.
The Arctic is referred to as the "Earth's air conditioner," moderating climate worldwide. More directly, Arctic species like polar bears, seals and walruses are becoming threatened as their habitat shrinks. The latest data may not be surprising, but it is not encouraging. It's another indicator that the world needs to take action to slow and reverse the effects of climate change, which means reducing our emissions of carbon dioxide and other greenhouse gases. To that end, there was no good news from the latest round of world climate talks, where nations were unable to reach consensus on key issues, according to AFP.
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