Friday, February 02, 2007

Global Warming

A new report by the Intergovernmental Panel on Climate Change has just been obtained by the press:

The world's leading climate scientists said global warming has begun, is "very likely" caused by man, and will be unstoppable for centuries, according to a report obtained Friday by The Associated Press.

The scientists - using their strongest language yet on the issue - said now that world has begun to warm, hotter temperatures and rises in sea level "would continue for centuries" no matter how much humans control their pollution. The report also linked the warming to the recent increase in stronger hurricanes.

"The observed widespread warming of the atmosphere and ocean, together with ice-mass loss, support the conclusion that it is extremely unlikely that global climate change of the past 50 years can be explained without external forcing, and very likely that is not due to known natural causes alone," said the report by the Intergovernmental Panel on Climate Change - a group of hundreds of scientists and representatives of 113 governments.

The phrase "very likely" translates to a more than 90 percent certainty that global warming is caused by man's burning of fossil fuels. That was the strongest conclusion to date, making it nearly impossible to say natural forces are to blame.

What that means in simple language is "we have this nailed," said top U.S. climate scientist Jerry Mahlman, who originated the percentage system.

Nice that we are mostly all agreed on that caused by humans bit. Too bad it looks like too late to do anything much about it. I hope I'm wrong in understanding the conclusions of the report that pessimistically.

The politics of all this is quite interesting:

The senior authors of the report, from the Intergovernmental Panel on Climate Change, a U.N. body convened every five years or so, have been inundated with e-mail messages and calls from some of the 650 other authors and outside experts eager to see findings tweaked in one direction or another.

With the clock ticking down and translators juggling six official languages, and government representatives trying to ensure that findings do not clash with national interests, tussles have intensified between climate experts and political appointees from participating governments.

Scientists involved in the discussions said today that the U.S. delegation, led by political appointees, was pressing to play down language pointing to a link between intensification of hurricanes and warming caused by human activity.

I don't know what to say about that all.