TUCSON -- A public draft of a U.S. Department of Agriculture (U.S.D.A.) report scheduled for release today includes findings that climate change already has inflicted major damage on large sections of the western United States and predicts impacts will spread to more areas and become more severe.
The 227-page draft USDA report, "The Effects of Climate Change on Agriculture, Land Resources, Water Resources, and Biodiversity," was culled from reviews of more than 1,000 publications. It is one in a series of 21 analyses of global warming by federal agencies conducted under the auspices of the U.S. Climate Change Science Program, which coordinates the climate change research activities of U.S. government agencies.
The full draft USDA report covers several topics and examines impacts across the United States. Included in the draft are estimates on a broad range of serious, often interconnected impacts in the West:
- Arid Lands: The West's arid lands comprise one of the nation's fastest-growing regions, and include the cities of Las Vegas, Phoenix, Albuquerque, Tucson and Salt Lake City. Predicted impacts include "continental-scale impacts on downwind ecosystems, air quality, and human populations" from increased wind erosion; major losses of signature desert species, such as saguaro cactus and Joshua trees; and increased drought, severe rainstorms, and erosion, which will help spark widespread desertification.
- Rangelands: Predicted impacts include "climate changes . . . (that) could impact the economic viability of livestock production systems worldwide;" major economic losses to the livestock industry from the combined impacts of climate change (heat waves, loss of quality food plants) and historic land management practices; and disappearing rangelands from the Great Plains to the desert Southwest, with grasses replaced by invasive, non-native shrubs and trees.
- Forests: Predicted impacts include major increases in the size and scope of insect infestations and wildfires. Because forests absorb and store carbon, dead forests release that stored carbon back into the atmosphere, which has the potential to further increase climate change impacts.
- Fish Stocks: Impacts include dwindling salmon runs, with some rivers becoming too warm to support any salmon at all; serious fresh-water stream damage from lower water flows, higher temperatures, silting from erosion and non-native plant invasions; major losses of cold-water lake fish habitat; and substantial degradation of water quality.
UPDATE: The final report is now out; not sure yet if any of the findings have been changed. USDA news release.