Archive for Sunday, November 7, 2004

Glacial melting on the increase, study shows

November 7, 2004


I have some bad news, good news and bad news.

First, the first bad news. It came from Richard Alley and Prasad Gogineni.

Alley is a Pennsylvania State University scientist. A couple of weeks ago, he explained to a small audience at Kansas University that Antarctica, over time, has been coolest when it gets the most sunshine.

On the other hand, Antarctica has tended to warm up when carbon dioxide levels in the atmosphere rise -- even if the sunlight striking the continent decreases.

In the past, Earth has seen periodic dramatic rises in carbon dioxide, Alley said. But they're nothing compared with what's likely to come in the next 200 years if we keep burning fossil fuel.

Eventually, Alley said, we'll reach atmospheric carbon dioxide levels that rival those found the last time the Earth had NO ice on its surface.

And what if all the Earth's ice melted? Among other things, policy wonks inside the Beltway would need scuba-diving equipment to get to work.

Gogineni's bad news showed up in a late September issue of Science magazine. The KU distinguished professor of electrical engineering and computer science, along with 17 colleagues at KU and elsewhere, reported accelerated glacial thinning.

In western Antarctica, the ice is melting faster than during the 1990s. The glaciers that rim the Amundsen Sea are discharging 60 percent more ice into the sea than they accumulate from snowfall.

About 253 cubic kilometers of ice move into that sea each year. That's a volume roughly equal to 241,000 Empire State buildings.

Gogineni said that previous estimates had been lower, at 150 cubic kilometers a year.

The 253 cubic kilometer figure would raise ocean levels worldwide more than .2 millimeters a year.

Gogineni said that people thought that all of Antarctica -- not just the glaciers around the Amundsen Sea -- was contributing that much to sea-level rises.

And now a pause for the good news -- at least "good" from my selfish, provincial perspective as a U.S. citizen living in the Midwest.

Alley said that sea-level rises of maybe a few feet are likely to cause trouble for Bangladesh, New Orleans and Venice, but that many of us will get off easier.

The most drastic impacts of planetary warming will be felt on the coasts and at the poles, he said.

Now for the last bad news.

Scientists speak in probabilities. To imagine the probability of how much we would suffer with a massive melting of ice, picture a bell-shaped curve, one of those things that looks like a snail in profile.

The probability that glacial melting would be troublesome -- but wouldn't be a disaster -- for those living in temperate zones is large, Alley said.

The size of that probability is like the area under the canopy of the snail shell.

But there's a small probability -- picture the head or tail of the snail -- that the whole thing could be much worse than that.

How much worse? Well, imagine the Florida coast being relocated all the way to, oh, say, Georgia.

It occurred to me, as Alley told me this, that although the election campaign of 2004 was depressingly mean, at least we were spared the environmental conversation.

But we won't be spared forever.

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