Our record-busting summer 2011 continues to be an object of fascination to climate scientists all over the world. Alongside floods in Thailand, drought in Eastern Africa and the European heat wave, the driest, hottest year in recorded Texas history has provided a case study for gauging the influence of climate change on weather extremes.
Researchers from Oregon State University, the University of Oxford and Exeter scrutinized last summer and -- with data from 2008 (the most complete set we have) and comparable La Niña years in the 1960s -- ran them through a set of computer models. When they threw the results on a scatter plot, the spread was dramatic: Texas was 20 times more likely to see heat extremes in 2008 than in years with similar oceanic conditions in the '60s. They found much the same for drought.
"This suggests that conditions leading to droughts such as the one that occurred in Texas in 2011 are, at least in the case of temperature, distinctly more probable than they were 40-50 years ago," says the study in the Bulletin of the American Meteorological Society.
Being ever-cautious scientists, they still offer a bit of equivocation. Tying a specific event like the drought to climate change is now possible, but mostly in terms of probability, the report says. Think of it this way: I know it's a stretch, but imagine a baseball player who's hitting 20 percent more home runs because he's juiced-up. Now, can you attribute any single home run to steroids? Maybe. But what you can definitely say is, all things being equal, each home run is 20 percent more likely to occur.
That's where climate science is now. The kind of drought that continues to hurt Texas' cattle industry and worry municipal water districts is more likely to occur because of climate change. It's this distinction that the authors fear may cause the public to become confused about whether climate change has anything at all to do with the drought. A previous NOAA study put it this way: It's still tricky to blame climate change for the inverse precipitation and temperature extremes we saw last summer. But what we can say for certain is that climate change poured gasoline on the fire.
