You're Getting Warmer

Last night I mentioned the report on global warming due on Friday from the UN's Intergovernmental Panel on Climate Change. Well, it's out, and you can take a look at the Summary for Policymakers (in PDF). Although the details don't seem so different from previous reports, scientists' commitments to them are much firmer. "Warming of the climate system is unequivocal," the report states, and it's "very likely" (which the report defines as greater than 90 percent likelihood) that humans are responsible.

We finally seem to have reached a point where many people will pay attention to these reports. This is the fourth report the IPCC has released since 1990, and in that time the reports have only become more certain. Some of the details have shifted, but doubt about these findings is much less than it once was.

Perhaps the most unsettling finding is that global warming is here, and no matter what we might do, it's not going away anytime soon. According to The New York Times:

<[Climate scientists] said the world was in for centuries of climbing temperatures, rising seas and shifting weather patterns — unavoidable results of the buildup of heat-trapping gases in the atmosphere.

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Moreover, the warming has set in motion a rise in global sea levels, the report says. It forecasts a rise of 7 to 23 inches by 2100 and concludes that seas will continue to rise for at least 1,000 years to come.

Even so, some scientists suggest that the report soft-peddles the likely extent of rising seas.

Dr. [Drew] Shindell, a climate expert at the NASA Goddard Institute for Space Studies who emphasized that he was speaking as an individual, said, "The melting of Greenland has been accelerating so incredibly rapidly that the I.P.C.C. report will already be out of date in predicting sea level rise, which will probably be much worse than is predicted in the I.P.C.C. report."

For their part, the scientists who put the report together seem to be leaning on a distinction that isn't quite clear to me:

The panel said there was no solid scientific understanding of how rapidly the vast stores of ice in polar regions will melt, so their estimates on new sea levels were based mainly on how much the warmed oceans will expand, and not on contributions from the melting of ice now on land.

Other scientists have recently reported evidence that the glaciers and ice sheets in the Arctic and Antarctic could flow seaward far more quickly than estimated in the past, and they have proposed that the risks to coastal areas could be much more imminent. But the climate change panel is forbidden by its charter to enter into speculation, and so could not include such possible instabilities in its assessment.

The scientists who are predicting the extent and effects of global warming won't take into consideration how the melting polar ice will affect things because they don't want to speculate. Perhaps the prediction of just how the ice will melt is too much to speculative to pin down, but how is the proper response to that to ignore its effects altogether?

Needless to say, news outlets near oceans are more concerned with how high the seas will rise than others. The South Florida Sun-Sentinel reports:

Experts are looking at predictions of sea level rise over the next 50 years from 2 feet to 10 feet.

A rise of 10 feet could swamp the state's highly populated coastline and send salt water spilling into the freshwater Everglades, said a leading South Florida-based scientist.

"It's an outlying estimate, but a 10-foot rise is within the realm of possibility," said Stephen P. Leatherman, director of the International Hurricane Research Center at Florida International University. "If that happens, not only do you have rising water to the east, but you have saltwater encroachment in the Everglades. It essentially becomes part of the ocean to the west of us."

"At that point, forget about Everglades restoration ... Most of this area is maybe 10 feet above sea level, so if you're talking about a 10-foot rise, and rising tide on top of that, then it's all over."

But the Sun-Sentinel also found naysayers:

"This is ... a U.N.-backed body that quite frankly is an advocacy group for controls on carbon emissions," said Tom Harris, executive director of the Natural Resources Stewardship Project, a leading clearinghouse for challenges to the science behind global warming. "We haven't seen the science they're drawing on in this report, and we're not going to see it tomorrow.

"There're over 10,000 reports that come out in any year on climate change ... and this group doesn't represent at all that many of the leading scientists in the field. Our own scientists have raised questions about the data they've seen from the IPCC."

Taking global warming more seriously means that we have to move from a report, even one getting more respect than it has in the past, to actual measures we can take to blunt the effect of rising temperatures. Until this discussion turns into action, we're not going to get anywhere.