With the start of the rainy season, fire activity in the Western United States has slowed. As of November 1, over 2.4 million acres had burned across California, with nearly 40% of that total coming from the Dixie Fire. Another 1.1 million acres burned in Oregon and Washington state, meaning the West Coast of the US saw 3.5 million acres go up in smoke.
The start of this year’s rainy season coincides with the climate-focused COP26 meeting of world leaders in Glasgow, and continued negotiations of climate provisions in the domestic Build Back Better bill. This year’s fires provide clear examples of just how much is at stake with current global and national negotiations.
When it comes to wildfires in the region, humans have modified just about every aspect of historical fire regimes, changing the frequency and severity of wildfires across our landscapes, and extending fire season to the entire year. These changes are ecosystem specific and have led to a cascade of consequences from reducing air and water quality to worsening climate warming by releasing greenhouse gases.
This year’s fires also reinforced that the impacts of wildfires are global, and not just when it comes to carbon emissions and our changing climate.
Wildfire smoke from fires in California and Oregon disrupted air quality as far east as our nation’s capital and we know that particulates from wildfires have been linked to everything from COVID-19 cases to deposition of black carbon on Greenland’s ice sheet. Even the rains that slowed this year’s fire activity provided a glimpse into the risks of increasingly severe wildfires, namely the higher risks of landslides, floods and debris flows in fire-denuded landscapes.
Climate change, on top of precarious forest conditions, has set the stage for dangerous wildfires, and without human action, these extreme seasons are likely to persist well into the future.
Legacy of fire suppression
Fire has shaped western North America’s landscapes for millennia. Until colonization, these landscapes burned regularly due to fires set by Indigenous communities to manage natural resources and wildfires ignited by lightning.
Spanish colonizers in the late 18th century expressed disdain for Indigenous land management practices and issued proclamations to criminalize intentional burning. In 1850, the first California legislature, convened before California became a state, passed An Act for the Government and Protection of Indians, which among other shameful provisions, outlawed intentional burning and even recommended fines or punishment for failing to “use proper exertions to extinguish the fire.” In 1911, following the “Great Fires of 1910,” the Weeks Act facilitated government purchase of millions of acres of land, and cemented fire suppression as federal policy.
This whole-scale fire suppression led to the accumulation of understory vegetation and debris that regularly occurring, low-severity fire had historically removed. This buildup of fuels increases the risk of high-severity fires that, in a departure from historical fires, can climb into the canopy and kill entire stands of trees. Fire suppression also increased the connectivity of our forested landscapes, meaning modern fires can spread more easily between continuous forested areas that historically were broken up by non-forest ecosystems like woodlands and grasslands. As a result, we see fires burning more severely over large areas, aggravated by climate-amplified fire weather, and with heightened risk to communities as we build further into the wildland urban interface.
Climate change and its impacts have added an additional layer of risk to these precarious forest conditions. This past season, we saw record-breaking heatwaves, and the continued emergence of a human-driven North American mega drought, drying out ecosystems and priming them to burn.
Climate change and science advances
Despite the daunting challenges that wildfires present, our understanding of current and future wildfires has developed rapidly, providing insight into California’s future and shining light on strategies for adaptation.
Warmer temperatures, due to climate change, have increased the drying power of the atmosphere (vapor pressure deficit), drying out forested ecosystems. Recent research has shown how forests are roughly 50% drier as a result of human-driven climate change, and how warmer, drier autumns are increasing the likelihood of extreme, late season fires. Similarly, dramatic winter rains in California can encourage the growth of grasses and other easy-to-ignite vegetation, which can then serve as tinder in summer months.
Climate change has also increased the burden on fire management and suppression agencies–the number of days of high fire danger have increased over the past 40 years, with even more dangerous days on the horizon. An increase in atmospheric drying power over 40 years, especially at night, strains fire-fighting resources, since expected nighttime moderation in fire behavior occurs for a shorter time period than it would have historically. New research has also linked short-term exposure to particulates in wildfire smoke to an increased risk of mortality, highlighting the consequences to not only those directly engaging with wildfires, but also global communities. In California, this exposure has increased dramatically over the past 5 years.
Future fire and fuel treatments
While the latest science forecasts a smoky future, the 2021 fire season also illustrated the importance, but also the limitations, of fuel reduction treatments. These treatments don’t stop forests from burning, but they do decrease the likelihood of high severity burns and extreme fire behavior, making the protection of human life and infrastructure more manageable.
In what many in the fire science community are hailing as treatment success, prescribed burns and fuel treatments changed the Caldor fire’s behavior, and assisted fire fighters in their efforts to protect communities and contain the blaze. Importantly, extreme fire weather, what the National Weather Service calls red flag conditions, can still overwhelm fuel treatments.
Investments in future wildfire resilience and adaptation
Following several extreme fire years, the need and urgency for investments in wildfire resilience in our forests and watersheds has been top of mind. Many strategies to reduce wildfire risk focus on restoring historical fire regimes to the landscape, through the reintroduction of intentional fire or the mechanical removal of biomass to mimic fire effects.
On a federal level, the House Rules Committee’s draft of the Build Back Better Act, earmarks $15 billion for wildfire risk reduction, including fuel reduction treatments like controlled burns and mechanical thinning, and funding for community wildfire defense grants. The Bipartisan Infrastructure legislation allows communities to apply directly to FEMA for hazard mitigation grants, and provides funds to NOAA to improve wildfire detection via satellite.
At a state level, California’s recent climate change package earmarks $1.5 billion for wildfire risk reduction and resilience, and includes funding to support the reintroduction of Indigenous-led intentional burning. Another recently-passed bill provides support to grow a workforce aimed at accelerating fuel reduction and mandates the creation of a cultural burning liaison to facilitate the restoration of Indigenous burning practices. These are just two examples of the multiple steps that California is taking to increase the resilience of its landscapes and protect its communities.
While federal and state action toward wildfire risk reduction represent important steps in our path towards resilience, treatments will still need to be implemented according to the best available ecological science, and consistent funding will be required to maintain fire-resilient forests and watersheds. Wildfires will always be a part of California’s future, but with strategic action and science-informed policies, we can influence the health of our ecosystems, and the type of fire that dominates our landscapes.