The Davis Mountains glow orange with flames (Credit: Frank Cianciola)
“It’s not just because the temperature is higher, it’s a combination of changes that are set in motion by the changing climate,” said David Cleaves, the climate change adviser to the chief of the U.S. Forest Service (Climate Central, April 27). “What’s happening today in Texas and the Southwest should be a wake-up call on climate change. These are the kinds of conditions that we expect to see more often as climate warms,” said Dr. Julia Cole, Professor of Geosciences, University of Arizona (Project on Climate Science, April 25)
More recent post:
Talking about the Texas disasters — climate and political
Earlier posts:
Ben Santer on the attribution of extreme weather events to climate change
U.S. Seasonal Drought Outlook, April-July 2011 (National Oceanic and Atmospheric Administration)
Climate Central, the independent, non-profit journalism and research organization, reported on April 27 (read the full article with accompanying graphics here):
Texas Wildfires Continue to Rage Amidst Historic Drought Conditions
By Dave Levitan
… The wildfires still burning through Texas are some of the worst the state has ever seen. Even after weeks of fighting, on April 27 there were still 17 major fires burning, covering about 573,000 acres, according to the Texas Forest Service. And since January, 840 fires have consumed more than 1.5 million acres. That already far eclipses the 293,000 acres that burned in Texas in all of 2010, and is approaching the 3.4 million acres that burned across the entire U.S. last year. …
The fires continue to rage, though, with help from a historically severe drought across the region. More frequent and intense droughts are a consistent finding of many climate projections, although attributing a particular drought, such as the current one, to climate change is fraught with complexity. “These are drought conditions that one might expect to see every 20 to 50 years,” said David Brown, regional director with the National Oceanic and Atmospheric Administration’s (NOAA) Regional Climate Services, in a conference call with reporters. …
Brown added that this drought was “a long time in coming.” Last month was the driest March Texas has had in the 117 years of available records, and a strong La Niña pattern in the Pacific Ocean “often corresponds to dry winter conditions in the southern United States,” Brown said. La Niña, characterized by cooler than average water temperatures in the equatorial Pacific Ocean, tends to steer the jet stream north of Texas, causing rains to bypass the state, as well as other parts of the southern tier. …
A Climate Change Connection?
It is hard to say exactly why this drought and the associated fires have been so persistent and devastating, but some experts note that long-term climate change may play a role.
“It’s not just because the temperature is higher, it’s a combination of changes that are set in motion by the changing climate,” said David Cleaves, the climate change advisor to the chief of the U.S. Forest Service, part of the Department of Agriculture. He added that rising temperatures and the potential for more frequent extreme weather events — both heavy rainfall as well as extended drought — could conspire to make conditions that much more conducive to fire.
“It starts with a lot of rain and a flush of growth, followed by extreme drought,” Cleaves said. “So you have even more vegetation to burn than you would have normally had because of the rain part, but then it’s drier because of the [drought].” This has played out to some extent in Texas, where the summer of 2010 was unusually wet, and the drought conditions that followed have left plenty of dry vegetation to serve as “fuel” for the fires. (See this related Climate Central graphic on how rains can actually lead to more fires in some areas) …
The Forest Service’s Quadrennial Fire Review, last published in 2009, suggested that this decade could see 12 million acres per year lost to fire in the U.S., an increase over previous averages. That raises questions about the role of climate change. In fact, climate change has already been found responsible for changes in the extent of areas burned in other regions of North America, like the forests of the Northwest, and is known to pose a threat to water availability in the Southwest. Future projections also show large increases in areas burned by wildfires as temperatures increase in the Western U.S. in coming decades. …
Hot Shot crews making their way to the fire line (Credit: Texas Forest Service)
From the Project on Climate Science, April 25:
Congressional Recess Confronted By Climate Reality
Denial of Science in Washington Overshadowed by Record Drought at Home
Washington, DC — Fresh off a vote in the House of Representatives to substitute ideology for science, Members of Congress returned home to Texas and the Southwest to find the most severe drought in more than 100 years. Humans are overloading the air with heat-trapping carbon and the result is a warming planet. Scientists have found that as warming continues, evaporation will increase and droughts will likely intensify. This is compounded by a climate change-induced shift northward of westerly storm tracks meaning less rain for the area. …
Members of Congress are misleading their constituents by not acknowledging that the climate is changing and heat-trapping pollution is responsible. A majority of the House voted to reject an amendment affirming an understanding of climate science to a bill in the House. While the bill would compromise the Environmental Protection Agency’s (EPA) ability to enforce the Clean Air Act, the rejected amendment simply called on Congress to at least accept the EPA’s scientific finding that greenhouse gas pollution threatens the health and welfare of Americans with a wide range of impacts, including more frequent and severe droughts and wildfires. …
Connie Woodhouse, Associate Professor Geography & Regional Development, University of Arizona:
“The current drought cannot be absolutely attributed to climate change, but it is consistent with the warming and drying conditions expected for this area based on climate change projections,” said Connie Woodhouse, Associate Professor Geography & Regional Development, University of Arizona. “Water resources in Texas are already stressed. The inevitable warming and drying in the future will only make droughts like this worse.” …
“Records from tree rings show us that droughts much more severe than any we’ve experienced to date have occurred in the western US in the past and there is no reason to think droughts of this magnitude could not occur in the future… but under warmer temperatures. Increases in water demand where supplies are limited, along with inevitable droughts, and the added effects of climate change dictate some serious thinking about the ways we use water,” added Dr. Woodhouse. …
Julia Cole, Professor of Geosciences, University of Arizona:
“What’s happening today in Texas and the Southwest should be a wake-up call on climate change. These are the kinds of conditions that we expect to see more often as climate warms,” said Dr. Julia Cole, Professor of Geosciences, University of Arizona. “Droughts like this can be triggered by natural causes like the La Niña that is now dying down in the Pacific. But the same pattern of drought is expected to become more frequent as the world warms. In both cases, we expect to see the storms that normally bring rain to the southwestern US move northwards, and our region to become drier. Warming temperatures will only make the drying worse.” …
“The science is unequivocal – the world is warming and human actions are principally responsible. Of course, human actions can also help us avoid the worst consequences of climate change, but not without real changes in business as usual,” added Dr. Cole.
U.S. Drought Outlook through July 2011 (Source: NOAA)