The report was prepared by a 13 federal agencies and was overseen by the White House Office of Science and Technology Policy, under the umbrella of a joint venture called the United States Global Change Research Program. Under a 1990 law, the group is required to report every 10 years on climate change effects on the environment.
The group found that the average U.S. temperature has risen 2 degrees Fahrenheit in the past 50 years and might rise another 4 to 11 degrees by 2100; precipitation has increased 5 percent overall over the past 50 years; and that Northern areas are likely to become wetter while the Southwest becomes drier.
“What we would want to have people take away is that climate change is happening now, and it’s actually beginning to affect our lives,” said Thomas Karl, director of the National Climatic Data Center at the National Oceanic and Atmospheric Administration, according to the New York Times. “It’s not just happening in the Arctic regions, but it’s beginning to show up in our own backyards.”
Karl spoke about the findings in a press conference Tuesday with NOAA Director Jane Lubchenco and chief White House science adviser John Holdren.
Michael McCracken, a lead author of the Global Change Research Program’s 2000 report, told the New York Times that the new report is a useful overview of the current state of climate science in the U.S., but that there is “not much that is new” added to what previous U.S. and international science panels have found.
However, the report comes at a key time, as Congress is considering a bill supported by President Obama that would place a national cap on greenhouse gas emissions for the first time.
Although the report does not deal with that issue directly, it does say that evidence of change is “unequivocal.” It sketches out some of the effects already being seen, including more powerful tropical storms, increased drought in the Southwest, heat waves in the Northeast and reduced mountain snowpack in the West and Northwest, and says that the severity of those effects in the future will depend at least partly on how quickly the U.S. and other nations reduce emissions.