The headline of a recent USA Today article trumpeted the claim, “Global warming raises water shortage risks in one-third of U.S. counties.” Fortunately, several drought studies in the peer-reviewed scientific literature contradict USA Today’s alarming claim.
The July 20 USA Today article is based on a single “study” produced by the Natural Resources Defense Council (NRDC), an environmental activist group that falls far short of being an objective scientific authority.
The peer-reviewed scientific literature, by contrast, shows precipitation increased and global soil moisture improved while global warming was occurring during the past century,.
A 2004 study in the peer-reviewed International Journal of Climatology examined long-term soil moisture trends throughout the Northern Hemisphere. The study reported, “The terrestrial surface is both warmer and effectively wetter.… A good analogy to describe the changes in these places is that the terrestrial surface is literally becoming more like a gardener’s greenhouse.”
A study published in the peer-reviewed Geophysical Research Letters in 2006 examined long-term precipitation and soil moisture trends in the United States. “An increasing trend is apparent in both model soil moisture and runoff over much of the U.S.… This wetting trend is consistent with the general increase in precipitation in the latter half of the 20th century. Droughts have, for the most part, become shorter, less frequent, and cover a smaller portion of the country over the last century,” the study reported.
A 2006 study in the peer-reviewed Journal of Hydrology analyzed long-term soil moisture trends throughout the world. It reported, “Evidence indicates that summer soil moisture content has increased during the last several decades at almost all sites having long-term records in the Global Soil Moisture Data Bank,”
Even the scientists who have been most vocal in sounding the global warming alarm admit there is no basis for the claims made by NRDC and USA Today. As prominent alarmist Gavin Schmidt—a colleague of prominent alarmist James Hansen at NASA’s Goddard Institute—told the Christian Science Monitor, “If you look at model projections of rainfall in arid regions—the American Southwest, the Sahel [in Africa], India, China—for 2050 or 2100, half the models say one thing, half the models say another thing.”
James M. Taylor ([email protected]) is managing editor of Environment & Climate News.