Wild fires are getting bigger and burning with greater intensity with an extended fire season, due in large part to climate change, according to testimony this week of Thomas Tidwell, Head of the US Forest Service to the US Senate Energy and Natural Resources Committee.
In his statement on Tuesday to the Senate Committee Tidwell said:
Around the world, the last two decades have seen fires that are extraordinary in their size, intensity and impacts. In Australia in 2009, the Black Saturday Bushfires killed 170 people. Domestically, Florida, Georgia, Utah, California, Texas, Arizona, New Mexico and Colorado, have all experienced the largest and/or the most destructive fires in their history just in the last six years. On average wildfires burn twice as many acres each year as compared to 40 years ago, and there are on average seven times as many fires over 10,000 acres per year.
In 2012 over 9.3 million acres burned in the United States. The fires of 2012 were massive in size, with 51 fires exceeding 40,000 acres. Of these large fires, 14 exceeded 100,000 acres. The increase in large fires in the west coincides with an increase in temperatures and early snow melt in recent years. This means longer fire seasons. The length of the fire season has increased by over two months since the 1970s.
"The largest issue we now face is how to adapt our management to anticipate climate change impacts and to mitigate their potential effects," Tidwell told the committee.
Increasingly severe wildfires also have a huge monetary effect with Fire activities jumping from 13 percent of the U.S. Forest Service's total agency budget in 1991 to over 40 percent in 2012 according to Tidwell. This transfer of funding resources to fighting fires takes its toll on management and maintenaince of US forest activity including repair and upgrade of trail work like the Pacific Crest National Scenic Trail to prevent sedimentation and erosion damage to watersheds.
As the climate becomes drier along with higher, more extreme temperatures, the trend will be longer more intense fire seasons. There are also more people living in fire prone communities which will challenge wildfire management.
"The spread of homes and communities into areas prone to wildfire is an increasing management challenge. From 2000 to 2030, we expect to see substantial increases in housing density on 44 million acres of private forest land nationwide, an area larger than North and South Carolina combined (USDA Forest Service, 2005) . Currently, more than 70,000 communities are now at risk from wildfire, and less than 15,000 have a community wildfire protection plan or an equivalent plan. (USDA Forest Service , 2012)" said Tidwell.
We know the impact of extreme fire weather first hand in Australia, with the extreme heatwave in January 2013 causing extreme fireweather in South east Australia. The Tasmanian bushfires wiped out the town of Dunalley with people fleeing the inferno by boat. Prime Minister Julia Gillard later linked the intensity of the bushfire to climate change. This follows the catastrophic Black Saturday bushfires in Victoria in 2009 which killed 170 people.
Climate Models project drier conditions for US, more extreme fire weather
In December 2012 Scientists using NASA satellite data and climate models projected drier conditions likely will cause increased fire activity across the United States in coming decades. The analysis was based on current fire trends and predicted greenhouse gas emissions.
"Climate models project an increase in fire risk across the U.S. by 2050, based on a trend toward drier conditions that favor fire activity and an increase in the frequency of extreme events," said Doug Morton of NASA's Goddard Space Flight Center in Greenbelt, Md.
There is currently a substantial Soil Moisture anomaly for much of the US midwest and southwest. Reduced soil moisture affects humidity and contributes to drought conditions and the severity of fire weather. Soil moisture deficit is one of the indicators for Use in Prediction of Forest Fire Danger Index in Australia.
Watch on Youtube (33:47) the Press Conference from the AGU 2012 Fall Meeting, held on December 5, 2012 giving an overview of Fire in a Changing Climate. The presentation was done by Louis Giglio from University of Maryland, Christopher Williams from Clark University, Doug Morton from NASA Goddard Space Flight Centre, and Hsiao-Wen Lin from University of California at Irvine.
Christopher Williams, Assistant Professor of Geography from Clark University stated to a question: "The trends that we see in fire activity, as well as in carbon emissions, are consistent with what we would expect with continued rise in dryness across regions that are already flammable."
To another question on whether fire suppression and different fire management practices could change the trends we are seeing, Williams replied:
"One of the interesting things that we see now going on is that management activities currently taking place I would suggest are likely to become less effective as the climate changes and conditions become increasingly dry. The challenge here is that we have a changing backdrop of fire activity and fire risk. With climate changes that are forecast, and to some degree that have seen taking place so far we can expect management activities to be challenged even further to limit fire activity. There is an aspect of fuel associated with the forest flammability, and some of that is related to the climate change itself. For the most part we can expect management activities to be less effective if the trends in dryness that are forecast come to pass."
Drought still persists in much of the midwest. You can see this in the Seasonal drought outlook published on June 6, although Drought conditions have retracted in area from last year. Persistent drought damages crops, and impacts groundwater storage in aquifers, and exacerbates fire weather. Climate change may be driving the US Southwest towards a megadrought.
The low soil moisture and persistent drought sets the scene for another exceptional fire season in the United States. Already there are substantial wild fires near Santa Fe in New Mexico (Tres Lagunas and Thompson Ridge Fires in New Mexico), and in Southern California (Powerhouse fire).
North of Los Angeles, over 2000 fire fighters have been battling the Powerhouse fire for more than a week. More than 2,800 people and 700 homes have been subject to evacuation orders, according to the Guardian newspaper. At least 24 residences were destroyed with fighting the fire estimated to have cost $11.4 million. Over 30,000 acres have now been burnt by this fire.
Despite the fire season now extending an extra 2 months each year and doubling in the extent of land burnt in 2012, Federal wildland firefighters have been cut by 19 percent over two years.
- Thomas Tidwell, Chief USDA Forest Service, 4 June 2013 - Statement to Committee on Energy and Natural Resources US Senate on Wildland Fire Management (PDF)
- Common Dreams, 5 June 2013 - Hotter Planet Creating 'Extraordinary' Wild Fires says Head of US Forest Service
- NASA, 4 December 2012 - Climate Models Project Increase in U.S. Wildfire Risk
- Presentation at AGU 2012 - Fire in a Changing Climate (PDF)
- Image of soil Moisture anomaly from NOAA Climate Prediction Centre on Soil Moiture