Antarctic Sea Ice Increase: Fodder for Global Warming Skeptics?

| Thu Jan. 10, 2008 12:37 PM PST

antarctic200.jpgHold onto your hats, kids, because climate change skeptics are sure to have a field day with this one: Researchers have found that for the past 20 years, while ice in the Arctic has been rapidly decreasing, Antarctic sea ice has actually been increasing. "See?" The skeptics will say. "If the world really were getting warmer, then it wouldn't be all cold and icy in the South Pole."

But like many global warming denialist arguments, this one doesn't leave a whole lot of room for scientific nuance. Not all that science is fully understood yet, but until it is, you can fire back at doubting Thomases with a few basic facts: For starters, South Pole ice is much thicker than North Pole ice (2 miles in the Antarctic vs. 6-10 feet in the Arctic). Also, the ice in the north sits on open ocean, so it gets warmed from beneath&8212;while in the south, much of the ice sits on a continent.

Sydney Indymedia e-mailed renowned NASA climate scientist James Hansen, and he kindly put the Antarctic trends in some context:

All of the models, and the observations, have the central parts of Greenland and Antarctica growing faster because of global warming. This is a consequence of warmer air holding more moisture, thus increasing snowfall. But the net effect of warming on both continental ice sheets is mass loss, the increased melting being a larger effect than the increased snowfall.

And according to Hansen, not all of Antarctica's sea ice is increasing:

He also said "The fact that West Antarctica is shedding mass at a substantial rate, even though there is only small warming of surrounding sea surface temperatures, is a telling fact in my opinion, and a likely consequence of the warming ocean at depth, which affects the ice shelves that buttress West Antarctica, as discussed in our paper 'Dangerous human-made interference with climate: a GISS modelE study.'"

So there you have it: As usual, climate change is much more complex than skeptics would have us believe.

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