Thursday, April 30, 2009

Trends in Antarctic Ice

Recently, the news that the area of sea ice around Antarctica had increased was trumpeted as proof that climate change isn't happening. This kind of response is fairly typical, but it bears repeating that one single study or factor cannot prove or disprove the existence of global warming. In this case, researchers from the British Antarctic Survey and NASA determined that the ozone hole led to the increased ice. Lack of ozone results in more wind coming off the continent and cooling the ocean, and then more ice. So no victory here for climate change deniers.

The ozone hole will no doubt continue to shrink, thanks to the global ban on chlorofluorocarbons (CFCs), and conditions will return to normal, meaning the effects of climate change will be more obvious. But try telling that to Dimitri Zinchenko, a Russian Antarctic sea captain who asserts that his personal experience with the ice over the past few years does not lead him to believe in climate change. Certainly Captain Zinchenko is telling the truth about what he's seen, but again, one set of observations does not give the entire story about a complex phenomenon such as climate change. The effects of climate change will be and have been varied and unpredictable. The main problem is that global systems are being disrupted. Regardless of whether these disruptions are of the classic, ice-melting, thermometer-busting kind we've come to associate with climate change, they can have serious impacts on ecosystems and human systems.

So when you hear about Antarctic ice in the news, don't be confused when the news isn't all melting and sea rise and cities underwater oh my. There may be far less dramatic changes that are also slowly adding to the growing pile of evidence in favor of an anthropogenically warming world.

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