Chapter 8: The Impacts of Climate Change on Wildfires

• What are some of the factors that cause global warming?
• Which of these causes are from nature? Which ones are the result of human behaviour?
• Think of environmental problems in your own country. Which of these are natural and which are related to human interference?

Key Terms

anthropogenic effects/warming

effects or global warming due to human activity

disturbance agent

incidents that can begin to change the ecosystem

fire stewardship practice

application of knowledge of nature to use fire in a controlled and respectful way

old-growth stands

a group of trees that have been standing a very long time in the forest

prescribed burn

an organized, deliberate, and controlled burning of trees for forest management

reburn

an area in which there is a forest fire more than once in the same location and affecting the same trees

Reading

1. Since 2000, 15 forest fires have each caused at least $1 billion in damages in the United States (National Centers for Environmental Information, 2023). Wildfires have been a frequent issue in the Pacific Northwest for decades. Wildfire seasons continue to break records as the fires become more destructive every year. These disasters affect the economy, public health, and ecosystems throughout the West, including Alaska, Washington, Oregon, and California state.

2. A number of research studies suggest that climate change has been a key factor in increasing the severity of wildfires. The ongoing climate crisis increased the occurrence of heat waves and droughts and doubled the number of large-scale wildfires between 1984 and 2015 in the Westcoast United States (Wehner, 2017). Hence, thick wildfire smoke in late summer results in the most hazardous air quality in the world. Studying the relationship between wildfires and climate change helps communities better understand the role of the Pacific Northwest forests in the climate justice movement. It is crucial to advocate for the ever-changing environment around us and become prepared.

The Role of Wildfires

3. Wildfires are known to play an important role in the evolution of plants and animals in the Pacific Northwest (Brookham, 2020). They are a natural part of the ecosystem because they clean the forest floor of debris and reduce nutrient competition. The forests are comprised of vegetation in various stages of growth and regrowth, which is healthy, as it prevents wildfires from burning through the region uniformly.

4. Although some old-growth stands of trees have developed resistance to fire, high-intensity and repeated burns in recent years are causing significant damage to the forests. The extent of wildfire is closely related to several factors, including temperature, soil moisture, and the presence of organic matter. During a wildfire, numerous plant materials can become fuel -for instance, grasses, shrubs, trees, and pine needles (U.S. Department of the Interior, 2022). Fuels are getting drier in the Pacific Northwest forests and deadly wildfires are more likely to occur in short succession.

Ecological Changes

5. According to a study conducted by multiple ecologists in Seattle, longer fire seasons are expected in the Pacific Northwest forests due to climate change (Halofsky et al., 2020). The climate crisis leads to higher temperatures and shifting precipitation patterns. The warming climate decreases soil moisture, as well as enhances the drying of organic material that spreads wildfires. There is also evidence suggesting that the intensity and frequency of re-burns would increase, because of warmer and dryer conditions. Typically, it takes years for forests to regrow after a wildfire. High chances of re-burns make it especially difficult for ecosystems to recover.

6. Disturbance agents in forests are incidents such as droughts, which trigger ecological changes more significantly in warmer weather. Great damage to vegetation and soils are done. Longer and more dramatic summer droughts in the western United States will contribute to an increase in the frequency of large wildfires, thus reducing tree densities and leading to changes in carbon pools (Westerling et al., 2006). The capacity of forests to absorb carbon dioxide would be reduced. Essentially, the increase in wildfire activity due to predicted warming in the Pacific Northwest might worsen the enhanced greenhouse effect.

Climate Models and Wildfire Projections

7. Given the considerable power that wildfires hold, the scientific community has been studying wildfire factors and identifying general correlations, which allows them to develop models that contain climate variables, and then make projections about future wildfires. The climate models help people understand how rising concentrations of greenhouse gases affect temperature, precipitation, humidity, and wind, and can help researchers predict the location and severity of wildfires. Statistical research has demonstrated that significant declines in summer precipitation led to an increase in wildfire occurrence in the mountain ranges of the Cascade and Rocky Mountains. In addition, early snowmelt is believed to correlate with high wildfire frequency, since it provides opportunities for an early start of fire season (de Place & DeStephano, 2019).

Human Effects on Wildfire Risk

8. The contribution of human activities to wildfires is worth further investigation. A major discovery found in the research of the University of California, Los Angeles, is that between 1979 and 2020, anthropogenic warming (global warming due to human activity) contributed twice as much as natural changes to the increase in fire risk (Zhuang, et al. 2021). Human factors are much more significant than natural ones regarding the [widespread increase in] wildfires in the western United States.

9. However, the relationship is complex. According to a publication by the Goddard Institute for Space Studies of NASA, there is little evidence about the human effect on droughts and precipitation deficits in the United States (Wehner, 2017). But a human influence has been found, with a high degree of confidence, on soil moisture deficits during warmer weather. Furthermore, human-induced warming is to blame for earlier snow melts and the reduction of snow water, which leads to greater risks of wildfires in the Pacific Northwest forests.

Solutions and Adaptations

10. The issue of intensified wildfires in the Pacific Northwest is complicated to address. What is most urgent is to do all we can to curb climate change because this will prevent the situation from worsening. Since higher wildfire risks are attributed to human-induced warming, we should acknowledge this and strive to solve global warming, which would make wildfires more predictable and less destructive.

11. Taking action on the climate crisis eases the burden on wildfire management. Forest managers, community leaders, and policymakers have to take sustainability into consideration. It is exceptionally crucial that we protect the carbon storage in the Pacific Northwest forests. Given the substantial biodiversity in the Pacific Northwest, there are often no universal solutions to all the forests. Some common approaches include the thinning of dense forests, removing fuels, and prescribed burning. Additionally, a key approach is to empower Indigenous communities and strengthen Indigenous fire stewardship practices (Ma, 2021). For thousands of years, precious traditional knowledge has allowed Indigenous peoples to control fires.

12. Along with [reducing] climate change and developing different approaches to wildfires themselves, adaptation is also important for regional populations. Measures could be taken to compensate for the destruction caused by intensified wildfires. The goal should be that both ecosystems and communities are able to recover and rebuild efficiently. Post-fire seeding can help initiate regrowth in forests, although further scientific research is needed.

13. There are groups of people who are more vulnerable than others to the consequences of climate change: people with low incomes, women and children, and people of colour. These groups face challenges related to affordable and fire-safe housing in low-hazard areas (Wibbenmeyer, 2021). Communities could invest in air filtration systems in public buildings, preferably with support from state governments in the Pacific Northwest. Electric utility companies may improve equipment and infrastructure to avoid incidents such as large outages. Combating the intensified wildfires due to climate change requires collective effort and well-planned actions.

(1120 words)

Comprehension Questions

1. What is the key factor mentioned for the increase in the severity of wildfires on the North American west coast?
2. Give two examples of ways that climate change specifically contributes to wildfires.
3. What do climate models help us to understand? What specifically can this help us to understand about wildfires?
4. In what ways have humans contributed to the problem of increasing wildfires? Give one specific example.
5. What are some ways that we can address climate change and reduce the incidence of wildfires? Give two specific examples.

Chapter 8 Answer Key

Key Vocabulary

Vocabulary Practice

Definitions Chapter 8

Fill in the Blanks Chapter 8

Collocations Chapter 8

References

Brookham, L. (2020, September 17). Why are fires in the Pacific Northwest getting worse? Cascade Forest Conservancy. https://www.cascadeforest.org/2020/09/15/why-are-fires-in-the-pacific-northwest-getting-worse/.

de Place, E. & DeStephano, P. (2019). How does climate change affect northwest wildfires? Sightline Institute, https://www.sightline.org/2019/08/14/climate-change-affect-wildfires-season-northwest/

Halofsky, J.E., Peterson, D.L. & Harvey, B.J. (2020). Changing wildfire, changing forests: The effects of climate change on fire regimes and vegetation in the Pacific Northwest, USA.” Fire Ecology, 16(1). https://doi.org/10.1186/s42408-019-0062-8.

Ma, M. (2021, August 2). New report: State of the science on western wildfires, forests and climate change. UW News. https://www.washington.edu/news/2021/08/02/new-report-state-of-the-science-on-western-wildfires-forests-and-climate-change/

National Centers for Environmental Information. (2023). U.S. Billion-Dollar Weather and Climate Disasters. National Oceanic and Atmospheric Administration. https://www.ncei.noaa.gov/access/billions/

U.S. Department of the Interior (2022, April 20). Fuels management. Office of Wildland Fire. https://www.doi.gov/wildlandfire/fuels.

Wehner, M.F., Arnold, J.R., Knutson, T., Kunkel, K.E. & LeGrande, A.N. (2017). Chapter 8: Droughts, floods, and wildfires. In D.J. Wuebbles, D.W. Fahey, K.A. Hibbard, D.J. Dokken, B.C. Stewart, & T.K. Maycock (Eds.). Climate science special report: Fourth national climate assessment, volume I. U.S. Global Change Research Program, pp. 231-256, https://doi.org/10.7930/j0cj8bnn.

Westerling, A. Hidalgo, H.G., Cayan, D.R. & Switnam, T.W. (2006). Warming and Earlier Spring Increase Western U.S. Forest Wildfire Activity.” Science, 313(5789), 940–43, https://doi.org/10.1126/science.1128834.

Wibbenmeyer, M. (2021, October 21). Trends and solutions in wildfire management. Resources. https://www.resources.org/archives/trends-and-solutions-in-wildfire-management/

Zhuang, Y., Fu, R., Santer, B.D., Dickinson, R.E. & Hall, A. (2021). Quantifying contributions of natural variability and anthropogenic forcings on increased fire weather risk over the western United States.” PNAS, 118(45). https://www.pnas.org/doi/10.1073/pnas.2111875118