This blog is a re-post from the Media Matters research page. Read the entire post here, which includes individual responses from fire scientists (some from the CFSC) on the connections between climate change and wildfire.
News Outlets Avoid Topic Of Climate Change In Wildfire Stories
While numerous factors determine the frequency, severity and cost of wildfires, scientific research indicates that human-induced climate change increases fire risks in parts of the Western U.S. by promoting warmer and drier conditions. Seven of nine fire experts contacted by Media Matters agreed journalists should explain the relationship between climate change and wildfires. But an analysis of recent coverage suggests mainstream media outlets are not up to the task -- only 3 percent of news reports on wildfires in the West mentioned climate change.
Only 3 Percent Of Wildfire Coverage Mentioned Long-Term Climate Change Or Global Warming. The major television and print outlets largely ignored climate change in their coverage of wildfires in Colorado, New Mexico and other Western states. All together, only 3 percent of the reports mentioned climate change, including 1.6 percent of television segments and 6 percent of text articles.
METHODOLOGY: We searched Nexis and Factiva databases for articles and segments on (wildfire or wild fire or forest fire) between April 1, 2012, and June 30, 2012. News outlets included in this study are ABC, CBS, NBC, CNN, The New York Times, The Washington Post, The Associated Press, The Los Angeles Times, CNN.com, USA Today and The Wall Street Journal. MSNBC and Fox News were not included in this analysis because transcripts of their daytime coverage are not available in the Nexis database.
Evidence Suggests Climate Change Worsens Fire Risk In Parts Of Western U.S.
Climate Central: "Wildfires Require Several Factors To Come Together." A Climate Central article about the 2011 fire season noted that "major wildfires require several factors to come together," and that wildfires are strongly influenced by regional climate conditions, which in turn are influenced by global warming driven by greenhouse gas emissions:
As with most extreme weather and climate events, and their related impacts, major wildfires require several factors to come together in order [to] occur -- typically some combination of dry and windy weather, abundant and dry vegetation, and a spark, which can range from a carelessly tossed cigarette to a lightning strike.
Wildfires are a naturally occurring phenomenon closely tied to climate conditions, and as the world warms in response to rising amounts of greenhouse gases in the air, many studies show that wildfire frequency and severity will likely shift as well.
Historical variations in climate can explain much of the large year-to-year and decade-to-decade variations in Western US fire activity. Thus, climate change is already increasing wildfire activity in the Western US. This may seem surprising, given the number of other factors (including forest management practices) that are known to affect fire activity. [Climate Central, 6/21/11]
Major Climate Report: "Wildfires in the United States Are Already Increasing Due To Warming." In a comprehensive report commissioned by the Bush administration and released in June 2009, the U.S. Global Change Research Program said earlier snowmelt and drying of soils and plants have worsened wildfires in Western states:
Wildfires in the United States are already increasing due to warming. In the West, there has been a nearly fourfold increase in large wildfires in recent decades, with greater fire frequency, longer fire durations, and longer wildfire seasons. This increase is strongly associated with increased spring and summer temperatures and earlier spring snowmelt, which have caused drying of soils and vegetation. [U.S. Global Change Research Program, 6/16/09]
The report included the following chart showing that the number of acres burned per fire has increased significantly since the 1980s:
[U.S. Global Change Research Program, 6/16/09]
A 2010 National Research Council report summarizing the state of climate science also stated that "the length of the fire season has expanded by 2.5 months":
[L]arge and long-duration forest fires have increased fourfold over the past 30 years in the American West; the length of the fire season has expanded by 2.5 months; and the size of wildfires has increased several-fold. Recent research indicates that earlier snowmelt, temperature changes, and drought associated with climate change are important contributors to this increase in forest fire. [National Research Council, 5/19/10]
Recent Study Found Western U.S. Particularly Vulnerable To Global Warming's Impact On Fires. From the New York Times' DotEarth blog:
Researchers using a decade of satellite data on fires and a suite of climate models have produced the first thorough global estimate of changes in the frequency of fires in the world's forests under greenhouse-driven global warming. There's ample uncertainty but the study, published today in the peer-reviewed online journal Ecosphere, points to a variety of outcomes, with fires likely becoming more frequent in zones you might expect -- like temperate North America and particularly the western United States -- but rarer in the tropics. [New York Times, 6/12/12]
National Research Council: Warming Expected To Expand Area Burned By Wildfires In Western North America. In a 2010 report, the National Research Council said that "for warming levels of 1°C to 2°C, the area burned by wildfire in parts of western North America is expected to increase by 2 to 4 times for each degree (°C) of global warming." Particularly vulnerable areas "include the Pacific Northwest and forested regions of the Rockies and the Sierra," according to the report, which also included the following map showing projected increases in "area burned for a 1°C increase in global average temperature" relative to the median annual area burned from 1950-2003:
[National Research Council, 6/16/10]
Warming Has Boosted Tree-Killing Beetles, Adding Fuel For Fires. A National Academies website notes that the warming trend has boosted the population of bark beetles that kill trees in western forests:
This increase in wildfire is a legacy of both a changing climate and decades of total fire suppression that has resulted in a buildup of dead fuels. One important factor is drought. Wintertime precipitation is increasingly falling as rain instead of snow, and the snow that does accumulate is melting earlier in the spring--decreasing the amount of water available in the late summer months and contributing to longer and more intense droughts. Compounding the effects of these droughts is the increased susceptibility of drought-stressed trees to attacking insects. In the last decade, a bark beetle epidemic has exploded across 18,000 square miles of western mountain forests. Milder winter temperatures kill fewer beetles in their budworm phase than the colder winters of the past, helping to increase the bark beetle population, with devastating effects. As the beetles kill vast areas of forest, they leave standing dead wood, fueling even larger wildfires. [National Academies, accessed 6/28/12]
Responding To Increased Fire Risk Requires Policy Change, Vigilance Regarding Latest Science. The U.S. Global Change Research Program recommended that policymakers become versed in "what the latest climate science implies for changes in types, locations, timing, and potential severity of fire risks over seasons to decades and beyond" and change policy accordingly:
Living with present-day levels of fire risk, along with projected increases in risk, involves actions by residents along the urban-forest interface as well as fire and land management officials. Some basic strategies for reducing damage to structures due to fires are being encouraged by groups like National Firewise Communities, an interagency program that encourages wildfire preparedness measures such as creating defensible space around residential structures by thinning trees and brush, choosing fire-resistant plants, selecting ignition-resistant building materials and design features, positioning structures away from slopes, and working with firefighters to develop emergency plans.
Additional strategies for responding to the increased risk of fire as climate continues to change could include adding firefighting resources and improving evacuation procedures and communications infrastructure. Also important would be regularly updated insights into what the latest climate science implies for changes in types, locations, timing, and potential severity of fire risks over seasons to decades and beyond; implications for related political, legal, economic, and social institutions; and improving predictions for regeneration of burnt-over areas and the implications for subsequent fire risks. Reconsideration of policies that encourage growth of residential developments in or near forests is another potential avenue for adaptive strategies. [U.S. Global Change Research Program, 6/16/09]