Speaker of the U.S. House Nancy Pelosi (D-CA) and Rep. Ed Markey (D-MA) convened hearings November 1 to investigate an alleged connection between global warming and the recent California wildfires.
But scientists have already determined global warming is resulting in more prevalent precipitation, moister soils, and less drought than has occurred in cooler climates.
The May 25, 2007 issue of Geophysical Research Letters reports, “An increasing trend is apparent in both model soil moisture and runoff over much of the U.S.” The study adds, “Droughts have, for the most part, become shorter, less frequent, and cover a smaller portion of the country over the last century.”
The July 2004 issue of International Journal of Climatology reported global rainfall and soil moisture have both risen dramatically during the past 50 to 100 years. “The terrestrial surface is both warmer and effectively wetter,” the journal reported. The wetter trend is especially well documented in North America, where “a good analogy to describe the changes … is that the terrestrial surface is literally becoming more like a gardener’s greenhouse.”
The National Oceanic and Atmospheric Administration reports, “A number of tree-ring records exist for the last two millennia which suggest that 20th century droughts may be mild when evaluated in the context of this longer time frame.”
Earth has a dynamic atmosphere, and there will always be periodic, localized droughts, scientists note. Southern California is one of the few regions that has recently experienced more drought than usual.
The droughts that occur in our current period of moisture and warmth are decidedly short term, limited in geographic reach, and quite minor when compared to those that have dominated colder climatic periods, scientists have learned.
It is disingenuous, to say the least, to blame localized drought conditions on global warming.
James M. Taylor ([email protected]) is a senior fellow of The Heartland Institute and managing editor of Environment & Climate News.