Assessing climate change in a drought-stricken state
By KATE GALBRAITH
26 August 2011 So, is this the result of climate change? Scientists hedge, particularly when it comes to the drought, because they are reluctant to pin any single weather event on climate change. They point to La Niña, an intermittent Pacific Ocean phenomenon that affects storms, as the immediate cause. “We can’t say with certainty whether this particular drought is in and of itself a product of climate change,” said David Brown, a regional official with the National Oceanic and Atmospheric Administration. However, Dr. Brown added, these kinds of droughts will have effects that are “even more extreme” in the future, given a warming and drying regional climate. Climate change, or global warming, has become a hot topic on the presidential campaign trail. Most scientists, including Dr. Brown, say humans are altering the climate by adding heat-trapping gases like carbon dioxide and methane to the atmosphere. Even so, Gov. Rick Perry, campaigning this month in New Hampshire, declared himself a “skeptic” that climate change is the result of human actions. Drought and high temperatures are consistent with climate-change forecasts for Texas. According to John Nielsen-Gammon, the state climatologist who was appointed by Gov. George W. Bush in 2000, about 80 percent of the models that were run for a 2007 report by the Intergovernmental Panel on Climate Change, a group overseen by the United Nations, predict declining precipitation for Texas. Climate change is already raising temperatures, Dr. Nielsen-Gammon said. Texas is one to two degrees warmer than in the 1970s, he said, and “by the middle of the century, it should be another two to three degrees warmer, give or take.” […] La Niña was present for four years during the 1950s drought, which still ranks as the worst in Texas history due to its longevity. Unusually high surface temperatures in the tropical Atlantic Ocean also helped cause that drought, and those have also been present in recent years. “The main factors that contributed to the 1950s drought are also in place right now,” Dr. Nielsen-Gammon said, adding that Texas is “likely to be” at the start of a multiyear drought, though it is hard to know with certainty. […]
