Dan's Outside

Polar ice cap gone by 2030?

This post at Weather Underground caught my attention since I had just seen a National Geographic program on the mechanism and effects of global warming on polar and glacial ice.

You’ll have to scroll down a bit a the links since the portion of the story referring to this year’s astounding decrease in the polar ice cap follows some other information.

Two excerpts:

None of our computer climate models predicted that such a huge loss in Arctic ice would occur so soon. Up until this year, the prevailing view among climate scientists was that an ice-free Arctic ocean would occur in the 2070-2100 time frame. The official word on climate change, the February 2007 report from the U.N.-sponsored Intergovernmental Panel on Climate Change (IPCC), warned that without drastic changes in greenhouse gas emissions, Arctic sea ice will “almost entirely” disappear by the end of the century. This projection is now being radically revised. Earlier this year, I blogged about a new study that predicted abrupt losses of Arctic sea ice were possible as early as 2015, and that we could see an ice-free Arctic Ocean as early as 2040. Well, the Arctic Ocean has suffered one of the abrupt losses this study warned about–eight years earlier than this most radical study suggested. It is highly probable that a complete loss of summer Arctic sea ice will occur far earlier than any scientist or computer model predicted. In an interview published yesterday in The Guardian Dr. Mark Serreze, and Arctic ice expert with the National Snow and Ice Data Center, said: “If you asked me a couple of years ago when the Arctic could lose all of its ice, then I would have said 2100, or 2070 maybe. But now I think that 2030 is a reasonable estimate. It seems that the Arctic is going to be a very different place within our lifetimes, and certainly within our children’s lifetimes.” While natural fluctuations in wind and ocean circulation are partly to blame for this loss of sea ice, human-caused global warming is primarily to blame. In the words of Dr. Serreze: “The rules are starting to change and what’s changing the rules is the input of greenhouse gases. This year puts the exclamation mark on a series of record lows that tell us something is happening.”

And…

One more point–global warming skeptics often criticize using computer model climate predictions as a basis for policy decisions. These models are too uncertain, they say. Well, the uncertainty goes both way–sometimes the models will underestimate climate change. We should have learned this lesson when the ozone hole opened up–another case where the models failed to predict a major climate change. The atmosphere is not the well-behaved, predictable entity the models try to approximate it as. The atmosphere is wild, chaotic, incredibly complex, and prone to sudden unexpected shifts. By pumping large amounts of greenhouse gases into the air, we have destabilized the climate and pushed the atmosphere into a new state it has never been in before. We can expect many more surprises that the models will not predict. Some of these may be pleasant surprises, but I am expecting mostly nasty surprises.

September 7, 2007 Posted by gdanmitchell | Environment | 4 Comments