Looks like we won't have to wait 50 years to see the effects of rising global temperatures, after all. According to a new study by the U.S. Climate Change Science Program, those changes are already well underway across the country:

"Climate change is currently impacting the nation's ecosystems and services in significant ways, and those alterations are very likely to accelerate in the future, in some cases dramatically," the report says. "Even under the most optimistic CO2 emission scenarios, important changes in sea level, regional and super-regional temperatures and precipitation patterns will have profound effects." ...

In addition, the number and frequency of forest fires and insect outbreaks are "increasing in the interior West, the Southwest, and Alaska," while "precipitation, stream flow, and stream temperatures are increasing in most of the continental United States" and snowpack is declining in the West.

The Agriculture Department, the study's lead sponsor, issued a statement yesterday highlighting some of the report's findings for farmers, noting that the higher temperatures mean that grain and oilseed crops will mature more rapidly but face an increased risk of failure and "will negatively affect livestock."

It's a good reminder, too, that even if the world does get its act together to avert runaway global warming (which could very well happen if temperatures rise more than 2 degrees above pre-industrial levels, thanks to a whole gamut of carbon-cycle feedbacks), there are still plenty of changes that won't be preventable, and the United States ought to start worrying about adaptation as well as mitigation. John McCain's big climate speech was sharp on this point, although massive adapatation efforts are certainly hard to square with his "slap a price on carbon and then get out of the way" philosophy. 

Also, one other footnote here: Back in 2005, the CCSP turned into something of a hornet's nest when one of its senior associates, Rick Piltz, came forward and accused a White House official of editing government climate reports in order to emphasize doubts about global warming and downplay the downsides. (The appointee in question, Philip Cooney, ended up resigning and scurried back to the oil industry.) Anyway, it's probably never safe to assume that the White House is being totally hands-off on this stuff, but the latest report does sound a lot more severe than anything else the administration has released to date, so maybe the appointees are finally backing off, at least on this front.

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