An era of poor sledding

But Zwally, a scientist at NASA's Goddard Space Flight Center in Greenbelt, Md., told MSNBC.com that the press release also follows an internal NASA change that seems to be taking place to allow scientists greater freedom.

A change in policy appears to be occurring after NASA scientist Jim Hansen complained about being silenced because of the Bush administration’s opposition to mandatory curbs on greenhouse gases that many scientists tie to global warming.

“A few months ago this press release might have been seriously edited or not approved,” Zwally said.

Note to global warming skeptics: if the Bush administration tries to muzzle someone, there is a good chance that those folks have actual facts, as opposed to industry-sponsored spin.

The upshot of the new report is polar ice sheets are shrinking dramatically, and that the process could be irreversible by the end of this century. However, the reports authors are still being cautious about linking the warming trends directly to human activity, although the wamring trends outlined in the report match those predicting warming due to greenhouse-gas emissions.

Based on satellite mapping of ice sheets and published in the Journal of Glaciology, the survey validated computer models projecting impacts on Earth from global warming.

“The survey documented for the first time extensive thinning of the West Antarctic ice shelves, an increase in snowfall in the interior of Greenland and thinning at the edges,” NASA said in the press release. “All are signs of a warming climate predicted by computer models.”

The press release followed the two Antarctica and Greenland studies, which included NASA research. And while those received considerable attention because of data that showed rapid changes in the ice, the press releases sent out with them did not emphasize global warming.

In the most recent press release, NASA did not directly tie the warming to humans and the burning of fossil fuels, which emits carbon dioxide, a key greenhouse gas.

But Zwally noted that the predicted climate warming cited in the press release is caused by manmade emissions. A natural warming cycle is technically possible, he said, but not likely given how closely the warming and models track.

Zwally said he expects to have even stronger satellite data within a year.

“We’re seeing the early signs of changes in the ice sheets,” he added. “The climate warming from greenhouse gases has really just started.”

I have no doubt whatsoever that this report will soon be rebutted by Oil Barons for Clean-Like Air or some similarly unbiased group, but those of us in the reality-based community can continue to advocate for greener policies knowing our advocacy is based on sound scientific evidence.

Update: In the comments, Mahigan provides a link to another grim climactic story.