Wildfires show a larger trend

  • Article by: RANDY LEE LOFTIS , Dallas Morning News
  • Updated: April 24, 2011 - 7:56 PM

La Niña may to be blame for current drought, but climate change may be worsening the conditions.


Firefighters Craig Howard, right and Jason Collard wait for radioed instructions as smoke rises from a nearby wildfire near Possum Kingdom, Texas, Tuesday, April 19, 2011.

Photo: LM Otero, Associated Press

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DALLAS - Texas horizons have been red lately, but not from great sunsets.

Wildfires have burned about 1.4 million acres and destroyed nearly 200 homes this year during one of the state's worst droughts. The calamities take on an apocalyptic, Mad Max quality, with exhausted firefighters attacking flames taller than they are and whole towns on alert for evacuation.

Scientists say the immediate cause is a La Niña, a recurring, monthslong pattern that blocks Texas' normal rains. But are the drought and fires also linked to climate change?

Going to the extremes?

Climate scientists say that question, though common whenever extreme weather arrives, is both unanswerable and misdirected. "By now, most people get that you can't attribute any single weather event on global warming," said John Nielsen-Gammon, the Texas state climatologist and a professor at Texas A&M University.

Short-term weather, even over months, is too variable to show a trend. Track weather over years or decades, however, and trends emerge, but not always the ones people expect.

Most climate models -- projections of future conditions -- say Texas will get less rainfall as global temperatures keep rising. But while the world has gotten hotter in the past 100 years, Nielsen-Gammon said, Texas rainfall has actually gone up by about 10 percent. Much of it has come from more-frequent extreme rainfall events rather than a general increase in normal rain.

Warmer air holds more water, contributing to extreme rainfall. However, higher temperatures also dry out plants and soil more quickly, worsening droughts -- perhaps including the ongoing one, Nielsen-Gammon said.

Future rain and drought patterns aren't certain, he said.

"But some things are clear: Temperatures have been going up, and models all agree that the temperature rise will continue unless we get some massive volcanic eruptions or the sun suddenly becomes much dimmer," he said.

Texas wildfires have consumed almost 4.7 million acres since 2006, according to the Texas Forest Service. Annual losses during that period varied greatly, from a high of nearly 2 million acres in 2006 to a low of 162,941 acres in 2007.

If the 2011 pattern continues, Texas will have had 1 million acres or more burned in three of the previous six years.

Climate scientist Katharine Hayhoe, a research associate professor at Texas Tech University in Lubbock, said Texas trends are already emerging -- especially a tendency toward more extreme rainfall events.

'It's either feast or famine'

"Here in West Texas, our rainfall's getting more variable," she said. "It's either feast or famine. ... We're not getting a lot in the middle."

Although no one drought or flood can be blamed on climate change, she said, the chances for such events might increase, like rolling dice loaded with an extra six. "You never know if the six you roll is the natural one or the climate-change one," Hayhoe said. "But you do know you're getting them twice as much as you used to."

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