New (Federal) Climate Report Foresees Big Changes
By ANDREW C. REVKIN
Published: May 28, 2008
The rise in concentrations of carbon dioxide in the atmosphere from human activities is influencing climate patterns and vegetation across the United States and will significantly disrupt water supplies, agriculture, forestry and ecosystems for decades, a new federal report says.
The changes are unfolding in ways that are likely to produce an uneven national map of harms and benefits, according to the report, released Tuesday and posted online at climatescience.gov.
The authors of the report and some independent experts said the main value of its projections was the level of detail and the high confidence in some conclusions. That confidence comes in part from the report’s emphasis on the next 25 to 50 years, when shifts in emissions are unlikely to make much of a difference in climate trends.
The report also reflects a recent, significant shift by the Bush administration on climate science.
During Mr. Bush’s first term, administration officials worked to play down a national assessment of climate effects conducted mainly during the Clinton administration, but released in 2000.
The new report, which includes some findings that are more sobering and definitive than those in the 2000 climate report, holds the signatures of three cabinet secretaries.
According to the report, Western states will face substantial challenges because of growing demand for water and big projected drops in supplies.
From 2040 to 2060, anticipated water flows from rainfall in much of the West are likely to approach a 20 percent decrease in the average from 1901 to 1970, and are likely to be much lower in places like the fast-growing Southwest. In contrast, runoff in much of the Midwest and East is expected to increase that much or more.
Farmers, foresters and ranchers nationwide will face a complicated blend of changes, driven not only by shifting weather patterns but also by the simultaneous spread of nonnative plant and insect pests.
Some invasive grasses, vines and weeds, for example, do better in higher temperatures and carbon dioxide concentrations than do crops and preferred livestock forage plants.
Corn and soybean plants are likely to grow and mature faster, but will be more subject to crop failures from spikes in summer temperatures that can prevent pollination, said one of the authors, Jerry L. Hatfield, a plant physiologist with the United States Department of Agriculture, in a conference call with reporters.
David E. Schimel, a lead author and director of a federal system of ecological monitoring stations, said in the call that mitigating emissions in the long run was still important even though not much could be done to change the short-term climate picture.
More at:
The New York Times
