Antarctic Ice Sheet Melting

The evidence keeps piling up that the Earth is warming. We have this article in today's Washington Post, which discusses recent findings by scientists that the ice sheet that covers the Antarctic is rapidly melting:

The Antarctic ice sheet is losing as much as 36 cubic miles of ice a year in a trend that scientists link to global warming, according to a new paper that provides the first evidence that the sheet's total mass is shrinking significantly.

The new findings, which are being published today in the journal Science, suggest that global sea level could rise substantially over the next several centuries.

The new Antarctic measurements, using data from two NASA satellites called the Gravity Recovery and Climate Experiment (GRACE), found that the amount of water pouring annually from the ice sheet into the ocean -- equivalent to the amount of water the United States uses in three months -- is causing global sea level to rise by 0.4 millimeters a year. The continent holds 90 percent of the world's ice, and the disappearance of even its smaller West Antarctic ice sheet could raise worldwide sea levels by an estimated 20 feet.

There isn't unanimous agreement among scientists as to the significance of these results. Nonetheless:

Richard Alley, a Pennsylvania State University glaciologist who has studied the Antarctic ice sheet but was not involved in the new research, said more research is needed to determine if the shrinkage is a long-term trend, because the new report is based on just three years of data. "One person's trend is another person's fluctuation," he said.

But Alley called the study significant and "a bit surprising" because a major international scientific panel predicted five years ago that the Antarctic ice sheet would gain mass this century as higher temperatures led to increased snowfall.

"It looks like the ice sheets are ahead of schedule" in terms of melting, Alley said. "That's a wake-up call. We better figure out what's going on."

In other words we may not exactly know what's going on, but we'd sure as hell had better figure it out. Why? Besides what global warming could do to the coastal regions as the caps melt, it could have other severe consequences:

At the other end of the temperature spectrum, two South African researchers are reporting today in Science that their computer models indicate that by 2100 climate change may rob the south and west of Africa and areas in the upper Nile region of a significant portion of their current water supply. Warming may reduce the rainfall needed to replenish up to 25 percent of Africa's surface water, said Maarten de Wit and Jacek Stankiewicz at the University of Cape Town in Rondebosch, South Africa.

"Water is essential to human survival," they wrote, "and changes in its supply can potentially have devastating implications, particularly in Africa, where much of the population relies on local rivers for water."

We don't spend a lot of time on the issue of global warming here at TWM. But you'll find no one on this blog who believes that global warming is not a critical issue. The signs are troubling, and the potential consequences could be devastating. And we're running out of time to do anything about it.