Humans Are Only Partially Responsible For Melting Arctic Ice; The Rest Is Natural
Finally, some news that makes us feel slightly less guilty about our fossil fuel habit.
Although the rapid melting of the Arctic ice has long been attributed to climate change, a study published in the journal Nature, suggests that this may only be partially true. The rapid increase in warming and retreat of sea ice in the Arctic Ocean since 1979 may, in fact, be caused by the unusually cool waters of the Pacific Ocean.
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Qinghua Ding of the University of Washington in Seattle, and his colleagues at Monash University in Australia, and at the APEC Climate Center in South Korea analyzed temperature data from 1979 to 2012 and found that the Arctic was melting fastest in Greenland and Northeast Canada — a part of the world impacted by the North Atlantic Oscillation (NAO). The North Atlantic Oscillation (NAO) is a climate phenomenon in the North Atlantic Ocean which has a strong effect on winter weather in Europe, Greenland, the northeastern part of North America, North Africa, and even in Asia. In the years when the NAO is positive, westerly winds give Europe and North America mild winters cool summers and lots of rain. When the NAO is negative, however, you get bitterly cold winters, and heat waves in summer. In comparing temperature readings to how the NAO behaved you would expect that temperatures would be warmest and Arctic ice would melt fastest when the NAO is positive, but Ding found the opposite to be true. They also compared it to models of how the currents should behave with human forced climate change and again found no correlation.
These facts in conjunction with the fact that Arctic ice in the Pacific was melting less fast made Ding suspect that the explanation lay in the Pacific. While the waters around Greenland have been unusually warm, the waters in the Pacific have been unusually cool. Cooler waters lead to less evaporation, less hot air rising, and changed patterns of wind and rain over the Pacific. In effect, Ding discovered that the cooler Pacific has been driving waves of warm air at high altitudes into the North Atlantic — speeding up the Arctic melt. Paradoxically, this same, natural climatic cooling has been tempering the effects of climate change. When the cooling wears off, in roughly fifteen years or so, it may slow the Arctic sea ice melt — if there's any left — at the same time we're left to face the full brunt of our climactic impact.
Although there's a chance that what's happening in the Pacific is actually human made, most scientists don't seem to think so.
This doesn't leave us off the hook, however. Ding's research still points out that at least half of the melting Arctic is still related to human-made climate change. And with the planet on the line, half guilty, is all guilty.
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