More on the USDA's climate report

Last week's USDA report on the "effects of climate change on agriculture, land, and water resources, and biodiversity" is full of specifics like these:

• Grain and oilseed crops will mature more rapidly, but increasing temperatures will increase the risk of crop failures, particularly if precipitation decreases or becomes more variable.
• Higher temperatures will negatively affect livestock. Warmer winters will reduce mortality but this will be more than offset by greater mortality in hotter summers. Hotter temperatures will also result in reduced productivity of livestock and dairy animals.
• Forests in the interior West, the Southwest, and Alaska are already being affected by climate change with increases in the size and frequency of forest fires, insect outbreaks and tree mortality. These changes are expected to continue.
• Much of the United States has experienced higher precipitation and streamflow, with decreased drought severity and duration, over the 20th century. The West and Southwest, however, are notable exceptions, and increased drought conditions have occurred in these regions. (Meanwhile, the Las Vegas Sun reports on Las Vegas' water woes in part 1 of a series.)
• Weeds grow more rapidly under elevated atmospheric CO2. Under projections reported in the assessment, weeds migrate northward and are less sensitive to herbicide applications.
• There is a trend toward reduced mountain snowpack and earlier spring snowmelt runoff in the Western United States.
• Horticultural crops (such as tomato, onion, and fruit) are more sensitive to climate change than grains and oilseed crops.
• Invasion by exotic grass species into arid lands will result from climate change, causing an increased fire frequency. Rivers and riparian systems in arid lands will be negatively impacted.

The Los Angeles Times has this to say:

The Senate is scheduled to vote this week on a sweeping bill that would require carbon emissions to be slashed 70% by mid-century. Its chances for passage are slim; President Bush opposes it, as he has opposed all meaningful attempts to curb global warming, on the grounds that it would harm the economy. He ought to read the USDA study, along with a similar but more comprehensive report released last week by his science advisors, which specifies the effects of global warming and its very real costs.

The USDA analysis points out the quandary we're already in after decades of inaction: The impacts during the next few decades are unavoidable. "Much of this change will be caused by greenhouse gas emissions that have already happened," the report says. In other words, we have to plan for adjusting to climate change, as well as preventing it from spiraling into a crisis in this century and beyond.