Wildfires are becoming more frequent and severe as a result of climate change, as forests in arid parts of the world become hotter and drier. In the mid-1980s, wildfires in the United States consumed just under two million acres a year on average; now, eight million acres burn each year (1). We can expect to see more wildfires in the future, especially in regions with a Mediterranean climate and low rainfall in the summer, such as the western U.S. and Canada, Spain and Portugal, Chile, and parts of coastal Australia.

Wildfire-prone regions are warming — the western U.S. has warmed as much as 3.5℉ since 1901 (2). This leads to more droughts that dry out forests. In California, more than 147 million trees have died due to extreme droughts since 2010 (3). Dead plants and trees catch fire more easily than live plants, and provide more fuel for fires to burn. Climate change is also expanding the range of some invasive insects and plant diseases, creating more dead plants for fires to consume.

And there’s a feedback loop: wildfires intensify climate change by releasing large amounts of carbon dioxide (CO2) and other greenhouse gases into the atmosphere. California's 2018 wildfire season released nearly as much CO2 as did the state's electric power plants that year (4). During Australia’s 2020 bushfire season, wildfires pumped out more CO2 than the 116 least-polluting countries emit in a year (5).

Climate change is only one part of the problem: for almost a century, U.S. forest managers tried to put out all wildfires as quickly as possible. But many western plants, and the ecosystems they belong to, evolved with fire. The focus on "total suppression" has unwittingly built up dead plant matter that would otherwise have burned in smaller, less damaging wildfires.

Another issue is that in California, a lot of houses are being built in the “wildland-urban interface”—where development bumps into large tracts of wildfire-prone public lands, like national forests. In the continental U.S., the wildland-urban interface is the fastest growing land use type. That’s because housing shortages are pushing people to live further out from urban centers, and because developers are incentivized to build in these rural areas. Houses, businesses and infrastructure in this zone are most at risk for wildfire damage (6).

Even if we reduced greenhouse gas emissions to limit warming, there is enough dead plant matter in California to fuel 30 more years of worsened wildfires. And there isn’t a good way to get rid of that fuel without adding more emissions.

The most successful strategies for adapting to wildfires will likely be those that focus on learning to live with them, as people have learned to live with flooding in parts of the coastal South and along the Mississippi River. This is already happening in the United States. For example, after the 2011 Labor Day Wildfires, two Texas counties implemented a Community Wildfire Protection Plan – including restoring and maintaining natural areas, revisiting development incentives, and public engagement – to reduce the damage of future fires (7).

Published September 28, 2020.

Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International license (CC BY-NC-SA 4.0).

Photo Credit: U.S. Department of Agriculture via Flickr

FOOTNOTES

1 “Monitoring Trends in Burn Severity.” MTBS Fire Viewer, United States Geological Survey, 2020, www.mtbs.gov/viewer/index.html.
2 "Climate Change Indicators: U.S. and Global Temperature; Figure 3. Rate of Temperature Change in the United States, 1901–2015." United States Environmental Protection Agency, 2020, https://www.epa.gov/climate-indicators/climate-change-indicators-us-and-global-temperature#ref3.
3 2018 Tree Mortality Aerial Detection Survey Results. U.S. Forest Service, Pacific Southwest Region, 11 Feb. 2019, https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fseprd609295.pdf​.
4 “Wildfire Preliminary Emissions & Burned Area Estimates 2000–2019.” California Air Resources Board, 1 Oct. 2020, https://ww2.arb.ca.gov/wildfire-emissions; "California Greenhouse Gas Emissions for 2000 to 2017." California Air Resources Board, 1 Oct. 2020, https://ww3.arb.ca.gov/cc/inventory/pubs/reports/2000_2017/ghg_inventory_trends_00-17.pdf.
5 “Wildfires continue to rage in Australia.” Copernicus Atmosphere Monitoring Service/ECMWF, 6 January 2020, https://atmosphere.copernicus.eu/wildfires-continue-rage-australia.
6 Radeloff, Volker C., et al. “Rapid Growth of the US Wildland-Urban Interface Raises Wildfire Risk.” Proceedings of the National Academy of Sciences, vol. 115, no. 13, 2018, pp. 3314–3319., doi:10.1073/pnas.1718850115.
7 City of Austin. "Austin/Travis County Community Wildfire Protection Plan." 30 Sept 2020, http://www.austintexas.gov/page/austintravis-county-community-wildfire-protection-plan.