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New government climate report foresees big changes

Posted by: Aqua Blog Maven on May 28, 2008 at 5:19 am

From the New York Times:

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 be well below half the average from 1901 to 1970, and 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. Alaska is projected to see a doubling of runoff from precipitation over the same periods.

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 non-native 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 there was relatively high confidence in the report’s forecasts because it focuses on the next 25 to 50 years, a period when efforts to curb emissions of greenhouse gases are unlikely to have much effect. “Mitigation is very important,” he said in the phone call. “But over the next few decades, independent really of what happens to concentration trends, the word the physics community uses is we’re ‘committed’ to a certain amount of temperature change.”

Read the full text of this article from the New York Times by clicking here.

A much more extensive article from the San Diego Union-Tribune adds this:

Besides focusing on farming, the report addressed the likely future of the nation’s natural resources. Among other things, it predicted that forest and range fires will become more common, soil erosion will increase and signature plants in the Southwest – including Joshua trees – could disappear.

Unlike many climate reports that make projections for 2100, this research team limited its time frame to the next 25 to 50 years. Scientists’ climate models show much more certainty in the shorter time period than they do for a century or more. They said the world is locked into some amount of warming in the near term because of past greenhouse-gas emissions, but that the long-term future could be different if those emissions are lowered. “Slight changes in things like temperature and precipitation can potentially have dramatic effects,” said Steven Archer, a lead author of the new report and a professor of natural resources at the University of Arizona.

Climate change looks to be a mixed bag for California: in some cases, California might be able to grow more heat-tolerant crops, but on the other hand, rising temperatures will affect fruit size, reduce dairy production, and may necessitate relocation of certain crops. Some crops, such as corn, rice and beans, may become less productive, while other crops such as cotton and peanuts might benefit. However:

Whatever happens to specific crops, the overarching issue will be water – a commodity that’s in increasingly short supply in the West. The USDA report said a trend toward earlier snowmelt challenges irrigation systems that rely on the mountains releasing water slowly over several months. “If politically it continues to be impossible to build more water storage in (California), then that bodes ill for having enough irrigation water,” Sumner said.

Read the article from the San Diego Union-Tribune by clicking here.

From the U.S. Climate Change Science Program at www.climatescience.gov: The report referenced in the article can be found by clicking here; the press release from the US Department of Agriculture can be found by clicking here.

May 28, 2008 · Filed Under Climate change & water supply