What do Alaska Wildfires Mean for Global Climate Change?

July 31, 2019 | 3:56 pm
Public Domain
Carly Phillips
Research Scientist

Alaska is on fire.

During the (on-going) 2019 fire season, over 2 million acres have burned – an area roughly equivalent to that of Yellowstone National Park. In comparison to many fires in the conterminous United States, many fires in Alaska burn far away from population centers, and as such can be fought and responded to differently. However, to put the alarming nature of this season in context, the 2019 fire season in Alaska has already burned greater acreage than ALL fires in California during 2018 (~1.8 million acres), the year of the devastating Camp, Woolsey, and Carr fires. We can see in the figure below that 2019 is slated to burn far more acreage than an average Alaskan season and may be on a trajectory to surpass 3 million acres burned.

Trends in burned acreage and total emissions across recent, representative fire seasons in Alaska. Burned acreage data from historical fire information from Alaska Interagency Coordinating Center, calculated using uniform growth over the provided course of each fire. Points were connected by lines for visual clarity. Emissions estimated using data from Veraverbeke et al 2015, which integrates both biomass and soil combustion.

Alaska’s ecosystems are already some of the most vulnerable to climate change, with temperatures rising at a rate that’s twice the global average. Across the state, record breaking heat and drought have dried out Alaska’s ecosystems, priming them to burn.

While these fires pose risks to human life and infrastructure, they also exacerbate climate warming by releasing millions of tons of heat-trapping gases into the atmosphere as Alaska’s vegetation and carbon rich soils burn, meaning that the impact of this year’s fires could reverberate for generations.

Wildfire smoke forecast from UAFSMOKE showing PM2.5 levels over the state of Alaska. PM2.5 is a major component of wildfire smoke and a good proxy for air quality. Pink, purple, and red areas are unhealthy for sensitive groups like children and older adults.

Boreal forests are fire adapted, meaning that fire is a natural part of the ecosystem. In recent years, however, fires have become more frequent and intense, moving beyond the historic fire regime of these ecosystems. So now we’re seeing more fires that burn a larger area.

In the twenty years from 1980-2000, Alaskan fires burned approximately 13.9 million acres. In the last nineteen years, Alaskan fires have burned more than double that area, approximately 28.1 million acres.

Fire seasons of this magnitude can create dangerous conditions for those who live, work, and visit Alaska. Risk of fire has already led to evacuation of several communities throughout Alaska, and smoke from these fires can create conditions that far exceed the EPA’s clean air standards for particulate matter.

Even more human lives are at risk when you consider the individuals fighting fire and the smoke impacts that make being outdoors, even to research and respond to fire itself, a health hazard.

Beyond these immediate risks of fire, carbon emissions from these wildfires could exacerbate climate warming for decades to come.

In addition to the carbon emitted from the burning of trees and foliage during a wildfire, carbon stored within the soil and below ground can also be released. Alaska’s ecosystems store huge quantities of carbon both as permafrost and soil that has accumulated over millennia. Wildfires destabilize these stores of carbon by combusting soil and accelerating permafrost thaw, both of which release heat trapping gases to the atmosphere.

Global carbon storage, darker colors (indicating the most soil carbon) are largely in high latitude ecosystems. Riccardo Pravettoni, UNEP/GRID-Arenda

And when it comes to the quantity of these gases, Alaskan fires aren’t messing around.

In 2019, fires in the state have released roughly three times what Alaska emits annually from burning fossil fuels (Fires release ~99 Million Metric Tons of CO2), and 40% more than all 2018 fires in California (68 Million Metric Tons of CO2). In the 3 largest fire years on record (2004, 2005, and 2015), fires released approximately 8 times more.

To avoid devastating impacts of climate change, we must reduce emissions from all sectors, including protecting carbon that is already sequestered. While these fires and emissions present an unchecked liability when it comes to combating continued climate warming, they also may present an unusual opportunity – where we can fight climate change with a technique (fire management) that we already can implement successfully.  Although fire management is often ignored as a viable climate mitigation strategy, the increasingly large fires this season in Alaska suggest that we ought to reconsider and view management of Alaskan fires as critical intervention opportunity.