Wednesday, December 28, 2011

Punishing drought just getting started in Texas

Greg Harman in the Current (San Antonio): Natural weather cycles delivered the worst one-year drought in the historic record to Texas in 2011. Scientists examining tree rings had to go back as far as 1789 to find a worse one. It was global climate change, however, that supplied the added heat that further reduced precipitation and exacerbated an already ugly dryness into levels of record-breaking heat.

When Texas state Rep. Doug Miller suggested that State Climatologist John Nielsen-Gammon had said climate change was not involved, the typically cautious, Bush-appointee offered the Current his correction: "Global warming contributed to the high temperatures, especially with this drought. So it enhanced evaporation and decreased water supply and therefore made the drought more intense then it would otherwise have been." Apart from the body-blow the dry stretch gave growers and ranchers (statewide herds were reduced by an estimated 600,000), the drought wiped out as many as 500,000 trees — possibly as much as 10 percent of the forestland — according to preliminary estimates from the Texas Forest Service.

Not only will drought continue through 2012, according to Nielsen-Gammon, but the current period of "enhanced drought susceptibility" could run into the 2020s. While Gammon's October report to the Lege fails to raise any climate-change alarms beyond suggesting that "an increase of several degrees Fahrenheit by mid-century in Texas is well within the realm of possibility" others have forecast as much — and worse — for some time.

Back in early 2009, the U.S. Climate Change Science Program surveyed the range of international scientific literature to determine that the Western and Central United States is returning to an era of "megadrought" conditions capable of lasting for hundreds of years....

US Drought Monitor detail for the US south as of December 20, 2011

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