Wildfires - Global Warming Forecasts



Wildfires emit huge amounts of carbon dioxide, increasing the rate of global warming. That warming then increases the number and severity of wildfires.

"We may be underestimating how much carbon future fires will contribute to the atmosphere. 

The biggest concern I have is that it is possible that we are underestimating the positive feedback of fire to the climate system and affecting future climate." (1)

— Thomas Swetnam, Director
Laboratory of Tree-Ring Research
University of Arizona

2015 Wildfires - Forest Fires

2015.  By 2015 10 million acres of national forests may be at high risk of uncontrollable, catastrophic wildfires.  “In 1997, [the U.S. Forest Service] announced its goal to improve forest health by resolving the problems of uncontrollable, catastrophic wildfires on national forests by the end of fiscal year 2015. . . . However, because it lacks adequate data, the Forest Service has not yet developed a cohesive strategy for addressing several factors that present significant barriers to improving the health of the national forests by reducing fuels.  As a result, many acres of national forests in the interior West may remain at high risk of uncontrollable wildfire at the end of fiscal year 2015. . . . . In 1997, the Chief of the Forest Service adopted an internal agency recommendation to increase the number of acres on which fuels are reduced from about 570,000 acres to 3 million acres annually by fiscal year 2005 and to continue this level until the year 2015. 

However, GAO’s analysis of the agency’s initial plans and data indicate that even this level of effort may leave about 10 million acres of the current 39 million acres at high risk of catastrophic wildfire. . . . Our preliminary analysis of the Forest Service’s fuel reduction costs—which, according to the agency’s data average about $320 per acre for the combination of burning and mechanical removal that is necessary in the interior West—indicates that as much as $12 billion, or about $725 million a year, may be needed to treat the 39 million acres at high risk of uncontrollable wildfire by the end of fiscal year 2015.” (GAO, Western National Forests, A Cohesive Strategy is Needed to Address Catastrophic Wildfire Threats,  Report to the Subcommittee on Forests and Forest Health, Committee on Resources, House of Representatives, U.S. General Accounting Office, GAO/RCED-99-65, Washington, DC, April 1999, pp. 3, 4, 6, 8, 41, 45) 

Wildfire Forest Fuels Buildup

1909 U.S. Forest Service photograph of typical open Ponderosa Pine stand in the Bitterroot National Forest in Idaho.  GAO/RCED-99-65, p. 23

1989 photograph taken from the same spot in the Bitterroot National Forest in the same direction.  GAO/RCED-99-65, p. 24

2020 Wildfires - Global Warming

2020.  Global warming projected to cost New Mexico $488 million in wildfire-related costs in 2020 if greenhouse gases are not reduced.  “If nothing is done to reduce greenhouse gas emissions, New Mexico could experience some $3.2 billion in associated costs -- led primarily by wildfires and health-care.  This could translate to an individual tab of about 8 percent of annual household income by 2020, according to a report produced for the University of Oregon's the Climate Leadership Initiative's Program on Climate Economics by ECONorthwest. . .New Mexico will face more frequent wildfires amid prolonged heat waves, significant reductions in precipitation except for northern regions where increases are anticipated and increased seasonal droughts and floods.

Hotter weather -- with summer temperatures rising up to 12.6 [degrees] Fahrenheit over current averages by 2080 -- would increase air-conditioning costs, health-care complications and the state's death rate, especially for residents without access to home cooling. .  .‘Our assessment shows that climate change will impose many different types of costs on the citizens of New Mexico. . .We anticipate health-related costs of almost $421 million, wildfire-related costs of $488 million and energy-related costs of $248 million per year in 2020.’ [said the report's lead author, Ernie Niemi, a principal with ECONorthwest, a fellow with the Climate Leadership Initiative (CLI) and a [University of Oregon Program on Climate Economics] steering-committee member].” (“What if New Mexico doesn't address climate change?,” University of Oregon Media Relations, March 2, 2009)

2020.  Acres burned by wildfire in the State of Washington projected to increase by 50 percent by 2020 with an annual cost of fighting wildfires that may exceed $75 million. “Increased carbon dioxide will mean bigger trees, while higher temperatures increase the incidence of wildfire. The number of acres burned will increase by 50 percent by 2020 and by 100 percent by 2040, so the annual cost of fighting wildfires may exceed $75 million by 2020 - 50 percent higher than the current expenditures. That cost will double by 2040.  Lost timber sales, lost recreational and tourism opportunities, and health problems stemming from fires could be ‘many times higher’ than the cost of fire control, [Bob Doppelt, director of the Climate Leadership Initiative at the University of Oregon and co-author of 2007 study titled Impacts of Climate Change on Washington's Economy] said.” (Dan Richman, “Global Warming To Cost Us - Millions Will Be Spent On Higher Prices, Fixes, Study Says,” Seattle Post-Intelligencer, January 11, 2007)  View wildfire maps.

2025 Wildfires

2025.  By 2025 Montana's fire-suppression costs could triple to $84 million as result of climate change and new development growth.  “Climate change and new development in Montana will cause fire-suppression costs to skyrocket at the taxpayer’s expense if policymakers don’t better manage fire-prone areas, a recently released report [Solutions to the Rising Costs of Fighting Fires in the Wildland-Urban Interface] says. . . . Headwaters Economics conducted the study, which found that while it averages $28 million each year to protect Montana homes near forestlands from wildfire, new construction and global warming will fuel more fires and those costs could triple [to $84 million] by 2025. 

The projected $84 million or so in projected costs is more than the Montana Department of Agriculture’s current annual budget, according to the study.”  (Jessica Mayrer, Chronicle Staff Writer, “New development, climate change fuel firefighting costs,” Bozeman Daily Chronicle, Bozeman, Montana, August 28, 2009 citing findings in "Solutions to the Rising Costs of Fighting Fires in the Wildland-Urban Interface," Headwaters Economics, Bozeman, Montana, September 2009, updated December 2009, p. 12)

2030 Wildfires

2030.  Lightning-caused fires in Georgia projected to increase by 25 to 50 percent.  “In 30 years [2030], the trees [of Georgia] could all be gone. If rainfall declines 20 percent as projected by the Canadian [global warming] scenario [published in an April 2001 report by the National Science and Technology Council], most of Georgia's coastal plain, now part of the nation's ‘woodbasket,’ would be converted into open grasslands like that of Texas or Nebraska. Runoff into the nearby Savannah River would drop by 61 percent by 2030.  Without rainfall, the trees would dry out and become vulnerable to beetles and other pests. Lightning-caused fire would increase by 25 to 50 percent and would become the Southeast's prime landscape architect.”  (Jay Bookman, Staff, “Global Warming In Georgia: Southern-fried Forecast - Will climate changes be mild or dire? The latest news is chilling,” The Atlanta Journal Constitution, Atlanta, Georgia, July 29, 2001, p. B1 reporting findings in a April 2001 report published by the National Science and Technology Council)

2040 Wildfires

2040.  Number of acres burned by wildfire in the State of Washington projected to increase by 100% by 2040.  “Increased carbon dioxide will mean bigger trees, while higher temperatures increase the incidence of wildfire. The number of acres burned will increase by 50 percent by 2020 and by 100 percent by 2040, so the annual cost of fighting wildfires may exceed $75 million by 2020 - 50 percent higher than the current expenditures. 

That cost will double [$150 million] by 2040.  Lost timber sales, lost recreational and tourism opportunities, and health problems stemming from fires could be ‘many times higher’ than the cost of fire control, [Bob Doppelt, director of the Climate Leadership Initiative at the University of Oregon and co-author of 2007 study titled Impacts of Climate Change on Washington's Economy] said.” 

(Dan Richman, “Global Warming to Cost Us Millions Will Be Spent On Higher Prices, Fixes, Study Says,” Seattle Post-Intelligencer, January 11, 2007 citing findings in "Impacts of Climate Change on Washington’s Economy : A Preliminary Assessment of Risks and Opportunities," Yoram Bauman, Bob Doppelt, Director, Climate Leadership Initiative, University of Oregon, 541-346-0786, Sarah Mazze, Edward Wolf, Washington Economic Steering Committee and the Climate Leadership Initiative, Institute for a Sustainable Environment, University of Oregon, prepared for the Department of Ecology and Department of Community, Trade, and Economic Development, State of Washington, November 2006, p. 31)

2050 Wildfires

2050.  Forest wildfire burn area in the U.S. is projected to increase by over 50% and as much as 175% in some areas by 2050.  “The area of forest burnt by wildfires in the United States is set to increase by over 50% by 2050, according to research by climate scientists. The study [Impacts of climate change from 2000 to 2050 on wildfire activity and carbonaceous aerosol concentrations in the western United States], predicts that the worst affected areas will be the forests in the Pacific Northwest and the Rocky Mountains, where the area of forest destroyed by wildfire is predicted to increase by 78% and 175% respectively.

The research is based on a conservative temperature increase of 1.6 degrees Celsius over the next 40 years [2010-2050]. Published in the Journal of Geophysical Research, scientists also say that the increase in wildfires will lead to significant deterioration of the air quality in the western United States due to greater presence of smoke. . . . This work was funded by the U.S. Environmental Protection Agency (EPA) and National Aeronautics and Space Administration. Dr. Dominick Spracklen carried out the research whilst at Harvard’s School of Engineering and Applied Sciences (SEAS) in collaboration with Jennifer Logan and Loretta Mickley.” (NASA press release, “Wildfires Set to Increase 50 Percent by 2050,” NASA Earth Observatory, Twitter NASA EO, Greenbelt, Maryland, July 28, 2009 reporting findings in D.V. Spracklen, L.J. Mickley, J.A. Logan, R.C. Hudman, R. Yevich, M.C. Flannigan, and A.L. Westerlin, "Impacts of climate change from 2000 to 2050 on wildfire activity and carbonaceous aerosol concentrations in the western United States," Journal of Geophysical Research, Vol. 114, D20301, doi:10.1029/2008JD010966, published October 20, 2009. 

View Jennifer Logan's PowerPoint presentation on wildfires.

 

 Percentage Increase in Wildfire Area Burned
Western United States, 2050

This map graphic shows the percentage increase in area burned by wildfires, from the present-day to the 2050s, as calculated by the model of Spracklen et al. [2009] for the May-October fire season. The model follows a scenario of moderately increasing emissions of greenhouse gas emissions and leads to average global warming of 1.6 degrees Celsius (3 degrees Fahrenheit ) by 2050.  Most of the calculated increase in area burned is due to warmer temperatures in the West, which leads to dryer conditions and more serious wildfires.  Credit: Loretta Mickley, Harvard School of Engineering and Applied Sciences.  Spracklen et al, Oct. 2009.

Climate Change andWildfires Explained

Projected Increases in Areas Burned by Wildfires

This map shows the percent increase in expected wildfire burn areas.  Rising temperatures and increased evaporation from global warming are expected to increase the risk of fire.  The western United States is one of the regions most at risk for increased wildfire burns. 

The projections depicted in the map above were calculated based on a 1°C increase (rather than the benchmark 2°C increase) in global average temperatures, relative to the median area burned during 1950-2003.  The map is adapted from National Academy of Sciences, National Research Council of The National Academies, Climate Stabilization Targets: Emissions, Concentrations, and Impacts Over Decades to Millennia, The National Academies Press, Washington DC, February 11, 2011, p. 41.

 

When Wildfires Erupt as Water Supplies Diminish...

 

Wildfire impacts and policy questions:

  • Will there be sufficient firefighting personnel, deployment assets, equipment and evacuation resources to manage fire suppression on the scales projected in these forecasts?
  • How will fires coinciding with projected exceptionally long heat waves and water shortages impact fire suppression efforts and the availability of water supplies accessible for fire suppression and protection of property?
  • How will wildfire suppression efforts be impacted in drought areas when reservoirs dry up?
  • How will the volume of smoke from climate change wildfires on this scale impact the level of soot accumulation and heat-absorbing "dirty snow" on Arctic permafrost and the consequent rate of release of greenhouse gases from melting permafrost?
  • How will the volume of smoke from climate change wildfires on this scale impact the level of "dirty snow" soot accumulation and the consequent rate of snowpack melting and flooding?
  • How will fires occurring on this scale impact watershed security and the availability of water supplies?
  • How will fires coinciding with predicted heat waves and water shortages impact the availability of water supplies to meet water demand for hydroelectric power, agriculture, irrigation and drinking water consumption?
  • How many tons of greenhouse gases will be added to the atmosphere by fires on the scales envisioned in these forecasts?
  • Do the most recent wildfire forecasts and the forecasts summarized on this page, include greenhouse gas contributions from melting permafrost, oil shale and shale gas methane leaks in their greenhouse gas concentration and temperature estimates?  
  • If wildfires burn large areas of Arctic permafrost, leaving black charred surfaces on the burn site that absorb more heat than non-burned permafrost areas, how will this impact the permafrost melt rate as well as methane and other greenhouse gas release rates?
  • What are the probabilities of seasonal wildfires intersecting melting permafrost areas outgassing high levels of methane?
  • At what point does methane outgassing from melting permafrost pose significant risk of igniting large-scale combustible methane-fueled fires triggered by intersecting wildfires or random lightning strikes?
  • How will forecast underestimates affect the magnitude of wildfire impacts?
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    Listen to reports     of wildfires burning Arctic
    tundra and melting permafrost.

Wildfire Map

NASA Satellite view of fires around the world.  The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite shows fires around the world. Credit: NASA - Wildfires: A Symptom of Climate Change

Active Fire Map

California Wildfires and Global Warming in 2050

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Climate Change Fire Prediction

 2050 Wildfires and Global Warming (continued)

2050.  Projection that California property losses due to wildfires caused by climate change could increase by $2 billion a year by 2050. “California may be planning to slash greenhouse gas emissions, but it might also want to get busy finding ways to beat back what already lies in store for a warmer world, a new report suggests. ‘Extreme events from heat waves, floods, droughts, wildfires and bad air quality are likely to become more frequent in the future and pose serious challenges to Californians,’ said the report, a synthesis of 37 scientific papers. The report, the first update of a 2006 assessment on climate change in California, reaches starker conclusions than the first report did on flooding in the Bay Area and the state's diminishing rain and snow. Among the key finding [of the report was the finding that]:  Property losses due to wildfires could increase to $2 billion a year by 2050 and $14 billion a year by 2100.” (Mike Taugher, Contra Costa Times, “Warming to bring more flooding and fire, less rain to state,” The Oakland Tribune, Oakland, California, April 1, 2009 citing a draft version of Executive Summary of Climate Action Team Biennial Report to the Governor and Legislature, Climate Action Team, Sacramento, California, May 6, 2010)

2050.  20% increase in the number and area of wildfires in Yosemite National Park predicted for 2050.  “Wildfires within California's world famous Yosemite National Park could become more frequent and severe due to climate change, say scientists.  New research in the International Journal of Wildland Fire [published by the International Association of Wildland Fire] says warmer temperatures pose a twin threat.  As well as directly triggering fires, they could also melt the snow that covers the forest in winter.  Lightning strikes would then trigger more fires, burning more intensely. . . . That is because predicted higher temperatures will make vegetation more flammable and allow larger fires to take hold.  ‘But this research suggests that declines in snowpack will have an additional effect,’ says Dr Lutz. 

He and his colleagues estimate that [by 2050] warmer temperatures will trigger a 20% increase in both the number of fires within Yosemite and also in the area of forest that will burn with a higher severity.  These increased fires will be triggered by lightning strikes.  The reason that will happen is two-fold. First, there is some evidence to suggest that increasing levels of carbon dioxide in the atmosphere lead to more lightning strikes.  Second, and more important in Yosemite, Dr Lutz and his colleagues show that if snowpack cover in Yosemite during the winter falls by 17% by 2050, an amount predicted by conservative climate models, then lightning strikes are more likely to ignite forest fires in the park.  [Analysis of historic data showed that] when snowpack cover decreased in certain years, lightning-ignited fires increased exponentially. . . .

Overall, the number of lightning-ignited fires is predicted to increase by 19.1% from 2020 through to 2049, while the area that will burn at high severity each year will increase by 21.9%.  The projections produced by Lutz's team depend on warming continuing according to what is known as the [IPCC] B1 emissions scenario [Third Assessment Report published by the Intergovernmental Panel on Climate Change in 2001].” (Matt Walker, “Warming 'big threat' to Yosemite,” BBC, Monday, November 2, 2009 reporting findings in James A. Lutz, Jan W. van Wagtendonk, Andrea E. Thode, Jay D. Miller and Jerry F. Franklin, “Climate, lightning ignitions, and fire severity in Yosemite National Park, California, USA,” International Journal of Wildland Fire 18(7) 765–774    doi:10.1071/WF08117, published: 27 October 2009)

2085 Wildfires

Potential for Wildfires in California in 2085

2085.  Predicted wildfire frequency in California in 2085.  "The University of California at Merced prepared a study estimating how climate change may alter the frequency of large wildfires in California. The example [above] shows the potential for wildfires in 2085 as predicted by the GFDL climate projection model under the A2 emissions scenario.  The scale shows areas affected by different frequencies of wildfires under a climate change scenario by the end of this century. For example, 4.0 means the danger of wildfires would be four times more than in the historical period."  (California Climate Change Portal, "Potential Changes in Wildfire Regimes in California," Climate Change Policy & Climate Action Team, Sacramento, California, last modified December 3, 2009) 

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1) Aaron Mackey, Arizona Daily Star staff, “Fires: new climate threat?,” The Arizona Daily Star, Tucson, Arizona, April 24, 2009, p. A1 reporting findings in Bowman, Thomas Swetnam, et al, “Fire in the Earth System,” Science 481-484.DOI:10.1126/science.1163886, April 24, 2009

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Wildfires Global Warming