rp_0405_7.html
A Montana dust bowl?
In the West, global warming will raise temperatures rather than sea levels. To University of Montana professor Steve Running, that means big fires, parched streams and dust bowl agriculture.
In an April 8 column for the Billings Gazette, Running says full-fledged climate change – including shorter winters and drier summers – is already under way across the western United States.
Running directs UM's Numerical Terradynamic Simulation Group which operates the Montana Climate Center. In February, March and April, he notes, temperatures have increased from one-half to a full degree every decade for the last 30 to 40 years. This March was exceptionally warm and dry across the West and the fourth warmest in south-central Montana since 1895.
Evidence collected over the last 50 years implicates rising temperatures for the 15- to 30-percent decline in Montana's springtime snowpack and in bringing peak spring river flows an average of two weeks earlier. The snowpack holds about 75 percent of the West's water supply, acting as a reservoir that keeps streams flowing in the summer months.
Earlier snowmelt can lead to summer water shortages, affecting everything from agriculture and hydropower to fish habitat, Running writes. Already in the Yellowstone Basin, snow begins to melt five to 15 days earlier than it did 56 years ago.
Montana just experienced its 11th-warmest winter, with an average temperature for October 2003 through March 2004 at 3 degrees above normal. Also in 2003, Montana broke its all-time records for days without a trace of precipitation, 100-degree days and highest overnight temperatures.
The last statistic indicated reduced overnight moisture and humidity, and thus a much greater risk of fire, according to Montana Wilderness Association conservation director John Gatchell.