The rising temperatures have increased the frequency and severity of forest fires
Jeff Ott, a resident of Siskiyou County, was at home when he received multiple calls from coworkers alerting him that his house was in the path of an impending fire. Within two minutes, he snatched his computers and guitars and sped away in his ash-coated car. He was able to reach a safe hotel, but he wondered if anything would be left of his home when he returned. Mr. Ott is one of many people who was forced to evacuate Weed, California this September to escape what became known as the Mill Fire (1). While occasional fires are a feature of healthy forests, when they are too severe, they can devastate the environment and disrupt the natural ecosystem. Moreover, when these fires are near urban areas, they can pose serious threats to people, buildings, and public health. The rising temperatures caused by climate change have, quite literally, fueled these fires, increasing their frequency and intensity (2).
Any forest fire begins with a form of ignition, such as a forgotten cigarette, a neglected campfire, a lightning strike, or a spark from an electric wire. Once ignited, the fire requires nearby fuel to continue burning. This fuel could be anything flammable, including trees, grasses, or man-made buildings. The warmth of the fire will heat the fuel to its flashpoint, the temperature required to ignite. When the fuel reaches its flashpoint, the vapors contained in the fuel evaporate and mix with oxygen, producing the recognizable blaze of orange flames (3).
Since the industrial revolution, humans have developed a growing dependence on coal, natural gas, and oil to generate energy (4). Yet their efficiency has come at a price. Since the industrial revolution, the Earth’s temperature has been gradually increasing (5). Experts estimate that the average temperature of California has risen by 1.68 degrees Celsius since the 1800s (6). While less than two degrees Celsius may seem minuscule, it can lead to a significant difference in the damage caused by forest fires. The increase of one degree Celsius is estimated to augment the median burned area by up to 600% in specific kinds of forests (7).
A rise in global temperature causes rapid growth of surface air vapor pressure deficit (VDP). VDP is a measure of how dry the air is. When VDP is high, the air pulls moisture from the soil, leaving less water for plants to consume; when plants do not contain much moisture, fire can burn through them considerably faster because there is less water to evaporate (2,3). This can allow fires to spread over vast amounts of land with great speed. In 2020, the Glass Fire of California reached speeds of 40 miles per hour, burning through an acre of land every five seconds (8).
The rising temperatures caused by climate change are transforming forests in the Western United States into a tinderbox. The abundance of dry vegetation makes it easy for fires to ignite and spread across large amounts of land. As these forest fires increase in frequency and strength, they will continue to release carbon dioxide into the atmosphere. The latter will contribute to the vicious cycle of climate change, rising temperatures, and forest fires. If this cycle is to be broken, something must be done to minimize the chance of extreme fires occurring and to limit the growing threat faced by plants, animals, and people living within these forests (9).
- Feder-Sawyer, M. Hubler, S. Sasani, A. (2022, September 2). California wildfire burns at least 50 structures and forces thousands to flee. New York Times. Retrieved from https://www.nytimes.com/2022/08/01/us/california-mill-fire.html?searchResultPosition=2.
- Fu, R. (2021, November 9). Study Shows That Climate Change is the Main Driver of Increasing Fire Weather in the Western U.S. National Integrated Drought Information System. Retrieved from https://www.drought.gov/news/study-shows-climate-change-main-driver-increasing-fire-weather-western-us.
- Moore, A. (2021, December 3). Explainer: How Wildfires Start and Spread. NC State University. Retrieved from https://cnr.ncsu.edu/news/2021/12/explainer-how-wildfires-start-and-spread/.
- Brown, C. The Industrial Revolution. Khan Academy. Retrieved from https://www.khanacademy.org/humanities/big-history-project/acceleration/bhp-acceleration/a/the-industrial-revolution.
- Ritchie, E. (2018, September 7). Exactly How Much Has the Earth Warmed? And Does It Matter? Forbes. Retrieved from https://www.forbes.com/sites/uhenergy/2018/09/07/exactly-how-much-has-the-earth-warmed-and-does-it-matter/?sh=379289be5c22.
- Borunda, A. (2020, September 17). The science connecting wildfires to climate change. National Geographic. Retrieved from https://www.nationalgeographic.com/science/article/climate-change-increases-risk-fires-western-us.
- (2022, August 8). Wildfire climate connection. National Oceanic and Atmospheric Administration. Retrieved from https://www.noaa.gov/noaa-wildfire/wildfire-climate-connection#:~:text=Research%20shows%20that%20changes%20in,fuels%20during%20the%20fire%20season.
- Sweeney, D. (2020, September 29). Glass Fire burned 1 acre every 5 seconds in California. How fast can wildfires grow? The Sacramento Bee. Retrieved from https://www.sacbee.com/news/california/fires/article246092930.html.
- Brown, M. (2022, February 23). Climate change is causing more wildfires and governments are unprepared, says U.N. PBS News Hour. Retrieved from https://www.pbs.org/newshour/science/climate-change-is-causing-more-wildfires-and-governments-are-unprepared-says-u-n#:~:text=The%20report%20describes%20a%20worsening,burn%20through%20forests%20and%20peatland.
- Blumhardt, M. (2020, October 23). Two largest wildfires in Colorado history are burning at the same time, 10 miles apart. USA Today. Retrieved from https://www.usatoday.com/story/news/nation/2020/10/23/colorados-largest-wildfires-state-history-include-two-currently-burning/3743269001/.