NRDC 'Study' Misrepresents Warming's Effect on Water Supplies

“Global warming raises water shortage risks in one-third of U.S. counties,” blares a July 20 headline in USA Today. But don’t rush to fill and stockpile canteens, because this scare has as little merit as the dozens of other global warming “crises” that never lived up to their billing.

First, consider the source for the scare. USA Today is reporting on a “study” produced by the Natural Resources Defense Council (NRDC). A fanatical environmental activist group claiming global warming is a threat to water supplies (or anything else, for that matter) is about as objective and credible as a BP “study” claiming it was not to blame for the Gulf oil spill.

Second, global warming has been occurring for over a century and its impact on water supplies is well documented. As carbon dioxide levels have increased and as temperatures have gradually warmed, precipitation has increased and global soil moisture has improved. When an initial cause produces the same beneficial effect for over 100 years, there is little reason to run for the hills simply because a “study” by a fanatical advocacy group claims something entirely opposite.

Third, even the scientists who have been the most vocal in sounding the global warming alarm admit there is no basis to make the water shortage claims made by NRDC. As prominent and pugnacious alarmist Gavin Schmidt – a colleague of 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.”

Let’s take a look at what credible scientific sources (as opposed to fanatical environmental activist groups) say about precipitation and soil moisture trends as global temperatures have warmed.

A 2004 study in the peer-reviewed International Journal of Climatology examined long-term soil moisture trends throughout the Northern Hemisphere. ““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,” the study reported.

A 2006 study in the peer-reviewed Geophysical Research Letters studied long-term precipitation and soil moisture trends in the U.S. “-“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 studied long-term soil moisture trends throughout the world. “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,” the study reported.”

These peer-reviewed studies all tell us that global warming is not causing water shortages and drought. But don’t expect to see a story about them in USA Today.