As the Arctic heats up three to four times faster than the rest of Earth, hotter temperatures have super-charged northern fires, causing them to burn more area, more frequently, and more intensely.
These fires have a range of harmful impacts on communities, ecosystems, and wildlife in the north. When it comes to carbon, they represent a unique now-and-future threat to global climate. That’s because much of the boreal forest, which circles the high northern latitudes, is underlain by carbon-rich frozen ground called permafrost. Stocked with carbon from dead animal and plant matter that’s accumulated over hundreds to thousands of years, permafrost functions as Earth’s “deep freezer,” keeping the planet cool by keeping carbon out of the atmosphere.
When permafrost thaws, microbes begin to access and break down the once-frozen carbon, releasing it to the atmosphere where it contributes to warming. Wildfires accelerate this process by burning off the organic soil layer that protects permafrost— opening the door on the freezer. And as temperatures in the north rise and boreal forests dry out and experience greater climate stress, the fires these forests evolved with have become more frequent and severe, with consequences for both permafrost and our climate.
Why are boreal forests important to climate?
The boreal forest, the largest forested biome on Earth, covers large stretches of North America, Europe, and Russia and stores 25% of the planet’s terrestrial carbon. Roughly 80% of this carbon is stored belowground in the form of soil organic matter and permafrost. So when the forest burns, the carbon released from the trees is just the tip of the iceberg. Eighty percent or more of carbon emissions from boreal fires in North America and in central Siberia come from belowground combustion of soil organic matter.
Boreal forests have been reliable safekeepers of this belowground carbon historically by providing an insulating soil organic layer that protects permafrost. But increasingly severe fires are changing that picture.
What happens to permafrost when the boreal burns?
Wildfires threaten this belowground carbon in boreal forests in multiple ways, both during and long after the fire itself.
As a fire burns, it combusts the carbon stored in trees and plants, releasing it into the atmosphere along with smoke and harmful pollutants. Intense fires also burn through duff and soil layers that carpet the forest floor.
Burning these insulating layers exposes the permafrost below to warmer temperatures for years after a fire. A recent synthesis study led by Postdoctoral Researcher Dr. Anna Talucci of Woodwell Climate found that in burned sites across the boreal and tundra regions, the depth of seasonally thawed ground increased for two decades after a fire.
That means that long after a fire is extinguished, permafrost is still thawing and releasing carbon in the form of carbon dioxide and methane. Where this ground is rich in ice, it can sink and collapse after a fire, causing ponding, erosion, and creating bogs and wetlands that release methane.
All of this carbon released to the atmosphere contributes to further warming, which in turn contributes to drying forests, hotter temperatures, and more lightning ignitions in the boreal forests. That’s because warming has boosted both lightning ignition efficiency, or the likelihood that lightning starts a fire, and the number of lightning strikes in the region.
Average yearly burned area across Alaska and Canada has roughly doubled since the 1960s. Emissions from Canada’s 2023 fire season exceeded total fossil fuel emissions from every other nation except the U.S., China, and India for that year. And the frequency of extreme wildfires across the circumpolar boreal region increased seven-fold from 2003 to 2023.
These trends, amplified by the permafrost-fire feedback, worsen both Arctic impacts and global emissions and could hamper our ability to meet agreed-on climate goals.
Gaps in boreal fire research
Wildfires in boreal forests are already weakening the region’s carbon storage capacity, signalling a crucial shift in the global climate system. Addressing critical gaps in our understanding of the fire-permafrost feedback will help prepare for such shifts and their local and global implications.
Research teams including Permafrost Pathways and collaborators are refining tools to predict what increasing fires mean for regional and global carbon emissions and climate targets. Such insights are needed to inform the Intergovernmental Panel on Climate Change’s (IPCC) inventory of global emissions, which does not yet include fire emissions or fire-caused permafrost thaw emissions. Efforts to better model and predict the complex interactions between permafrost and fire are also critical to informing adaptation and management responses.
The region’s vastness, as well as geopolitical conditions, presents challenges to collecting field data. Here, modeling can help scale the insights from what field data is available. And developing more accurate fire maps in Alaska and Siberia, where less burned area satellite data exists, could equip researchers and communities with better near-real-time information. Long-term monitoring efforts that study pre- and post-fire conditions, such as those led by Łı́ı́dlı̨ı̨ Kų́ę́ First Nation at the Scotty Creek Research Station, are providing critical insights about fire’s acute and long-term effects on permafrost.
What we can do: solutions that support resilience
The impacts from widespread severe northern wildfires transcend boundaries, affecting health and ways of life for communities living in the Arctic and around the globe.
But there are solutions at hand. Cultural burning, an important practice for many Arctic Indigenous communities, can help boreal forests build resilience by removing fuels with low-intensity seasonal fire. And collaborative management approaches that suppress fires in permafrost regions have been shown to be a cost-effective climate mitigation tool that has co-benefits for human health and the global climate.
But the most important solution to help keep the global wildfire-permafrost feedback loop in check is to reduce greenhouse gas emissions. Lowering overall emissions will slow rising temperatures in the north and give communities, boreal forests, and other ecosystems a better chance to recover and to adapt.
Associate Scientist, Dr. Brendan Rogers has walked in many forests, but primary forests, he says, “just feel different.”
Rogers’ work often takes him to the cool, dark understories of black spruce and pine boreal forests, where he’s learned the subtle markers of a truly old, healthy, stable forest ecosystem.
“Generally cooler, often wetter, the trees are bigger but sparser and more likely to be conifers than shrubs or deciduous broadleaf trees,” says Rogers. “The ground is squishy to walk on, from the build-up of peat-like soils, mosses, and lichens.”
Primary forests are also a critical piece in the climate puzzle. They represent centuries of sequestered carbon, and every year they remain standing these forests continue to pull carbon from the atmosphere and lock it away in their trees and soils. They are also the subject of intense debates in forest management circles because, according to Rogers, despite knowing intuitively when you are standing in a primary forest, quantitatively identifying one is a tricky task.
That fact hasn’t deterred Rogers and his collaborator Dr. Brendan Mackey at Griffith University, from their work to identify and map metrics indicative of primary forests. In a joint project launched in 2018, Rogers and Mackey created an index of one such metric— forest stability.
Measuring forest stability
Forest stability is a measure of a forest’s resistance to disturbances, both manmade and natural. A stable forest has a high level of ecosystem integrity—a holistic term referring to the combination of ecosystem structure, function, species composition, and adaptive capacity. Stability reflects the ability of a forest to maintain all of those elements in the face of disturbance.
To quantify stability, Rogers and Mackey isolated two metrics that correlate heavily with integrity in forests— “greenness” and water stress. Greenness, also known as the fraction of photosynthetically active radiation (fPAR), indicates the amount of thriving, photosynthesizing plants. Water stress is an index of anomalies in vegetation moisture, indicating an area is dryer than usual. Both of these metrics can be remotely derived from satellites and, when combined with additional data, form an index of overall stability level.
This index was first tested by a postdoctoral scientist at Woodwell Climate, Dr. Tatiana Shestakova, who pulled data from NASA’s MODIS satellite sensor to map stability in sample regions in the Kayapo Indigenous Territory in the Brazilian Amazon and southern Taiga region of Siberia. After testing the model, Rogers, Mackey, and Shestakova expanded it to map stability across the entirety of Ontario, Quebec, boreal Siberia, and the Amazon rainforest.
The studies used a method called a time series analysis, which compares satellite data stretching back to 2002 to determine whether a forest had experienced a large-scale disturbance, reducing vegetation greenness and increasing water stress and thus lowering overall stability. These insights were only possible due to the long, consistent dataset produced by MODIS.
“It can be a little bit dicey to assess stability on shorter time scales,” says Rogers. “Because when you work with remote sensing data, forests can fluctuate year to year and sometimes you can’t completely eliminate things like cloud contamination or other errors from the data, so a longer time series helps smooth the data and lets you see the true patterns.”
Prioritizing protection for primary forests
These maps of stability have a crucial role to play in informing forest management policy.
“We’re trying to analyze and spatially map the ecological condition of forests,” says Mackey. “Because this information is needed to help guide where investments for forest protection and restoration go and how they should be prioritized.”
For a long time, Mackey says, management conversations did not distinguish between types of forests, lumping monoculture tree plantations into the same category as ancient natural forests, despite the vast differences in their carbon storage, biodiversity, ecosystem benefits, and overall resistance against disturbances.
“We weren’t seeing the forest for the wood,” Mackey jokes.
Quantifying a characteristic like stability makes it easier for managers to see the difference between the two, identify the forests best able to provide myriad ecological benefits, and ideally, prioritize those for protection.
Mackey uses the example of woodland caribou in Canada, which are considered a threatened species. These animals require large areas of intact primary forest to support successful populations. Overlaying forest stability on top of caribou habitat maps can help decisionmakers narrow in on the largest, highest-stability tracts of forest as top priority for conservation.
According to Rogers, a future goal would be to eventually link maps of forest stability with carbon estimates in order to create forest protection plans with climate mitigation in mind. Research in primary forests has shown they continue to sequester carbon year over year, even though tree growth has tapered off. With primary forests in many places under intense political and economic pressures, it will become even more important to demonstrate the many co-benefits of protecting the earth’s stable forests.
“There’s no forest anywhere that isn’t threatened,” says Mackey. “Development, infrastructure, roading, damming, logging, clearing for agriculture. It’s happening everywhere.”
Stable forests are resilient forests
Tracking stability of forests also allows us to approach a much harder-to-define characteristic of primary forests—resilience.
Stability and resilience go hand in hand, though they are not the same thing. While resilience speaks to an ecosystem’s adaptive capacity or its ability to recover to its original state after some disturbance, stability is a measure of resistance, which is why it correlates so highly to primary forests that haven’t experienced any recent large-scale disturbance.
“If the stability index is showing recovery, then there’s obviously some resilience happening, but beyond that, primary forests tend to be more resistant to certain disturbances,” says Mackey. “Sometimes resistance is better even than being resilient. You’re not destroyed in the first place.”
Highly stable forests do tend to have better adaptive capacities as well, which is why they are so critical to protect.
“By and large,” says Rogers, “forests are resilient.” The stable ones can handle disruptions, and if you leave them to recover they will do just that, as he and Mackey have seen in the data.
But resilience is not infinite. If you hit too hard too fast—overlapping disturbances on an already unstable forest—you can overwhelm its resilience. Fires, larger and more frequent as a result of climate change, have already begun to override boreal forests’ adaptation. And there are more changes coming as the planet continues heating up.
For now, at least, Rogers says, “resilience is still largely what we see out there.”
Fire is a necessary element in northern forests, but with climate change, these fires are shifting to a far less natural regime— one that threatens the ecosystem instead of nurturing it.
Boreal tree species, like black spruce, have co-evolved over millennia with a steady regime of low-frequency, high-intensity fires, usually ignited by lightning strikes. These fires promote turnover in vegetation and foster new growth. On average, every 100 to 150 years, an intense “stand-replacing” fire might completely raze a patch of forest, opening a space for young seedlings to take root.
But rapid warming in northern latitudes has intensified this cycle, sparking large fires on the landscape more frequently, jeopardizing regeneration, and releasing massive amounts of carbon that will feed additional warming. Here’s how climate change is impacting boreal fires.
Climate Impacts on Boreal Fire
In order for a fire to start, you need three things— favorable climatic conditions, a fuel source, and an ignition source. These elements, referred to as the triangle of fire, are all being exacerbated as boreal forests warm, resulting in a fire regime with much larger and more frequent fires than the forests evolved with.
Climate conditions
Forest fires only ignite in the right conditions, when high temperatures combine with dryness in the summer months. As northern latitudes warm at a rate three to four times faster than the rest of the globe, fire seasons in the boreal have lengthened, and the number of fire-risk days have increased.
In some areas of high-latitude forest, climate change has changed the dynamics of snowfall and snow cover disappearance. The rate of spring snowmelt is often an important factor in water availability on a landscape throughout the summer. A recent paper, led by Dr. Thomas Hessilt of Vrije University in collaboration with Woodwell Associate Scientist, Dr. Brendan Rogers, found that earlier snow cover disappearance resulted in increased fire ignitions. Early snow disappearance was also associated with earlier-season fires, which were more likely to grow larger— on average 77% larger than historical fires.
Fuel
The second requirement for fires to start is available “fuel”. In a forest, that’s vegetation (both living and dead) as well as carbon-rich soils that have built up over centuries. Here, the warming climate plays a role in priming vegetation to burn. A paper co-authored by Rogers has demonstrated temperatures above approximately 71 F in the forest canopy can be a useful indicator for the ignition and spread of “mega-fires,” which spread massive distances through the upper branches of trees. The findings suggest that heat-stressed vegetation plays a big role in triggering these large fires.
Warming has also triggered a feedback loop around fuel in boreal systems. In North America, the historically dominant black spruce is struggling to regenerate between frequent, intense fires. In some places, it is being replaced by competitor species like white spruce or aspen, which don’t support the same shaded, mossy environment that insulates frozen, carbon-rich soils called permafrost, making the ground more vulnerable to deep-burning fires. When permafrost soils thaw and burn, they release carbon that has been stored—sometimes for thousands of years—contributing to the acceleration of warming.
Ignition
Finally, fires need an ignition source. In the boreal, natural ignitions from lightning are the most frequent culprit, although human-caused ignitions have become more common as development expands into northern forests.
Because of lightning’s ephemeral nature, it has been difficult to quantify the impacts of climate change on lightning strikes, but recent research has shown lightning ignitions have been increasing since 1975, and that record numbers of lightning ignitions correlated with years of record large fires. Some models indicate summer lightning rates will continue to increase as global temperatures rise.
There is also evidence showing that a certain type of lightning— one more likely to result in ignition— has been increasing. This “hot lightning” is a type of lightning strike that channels an electrical charge for an extended period of time and tends to correlate more frequently with ignitions. Analysis of satellite data suggests that with every one degree celsius of the Earth’s warming, there might be a 10% increase in the frequency of these hot lightning strikes. That, coupled with increasingly dry conditions, sets the stage for more frequent fire ignitions.
Fire Management as a Climate Solution
So climate change is intensifying every side of the triangle of fire, and the combined effects are resulting in more frequent, larger, more intense blazes that contribute more carbon to the atmosphere. While the permanent solution to bring fires back to their natural regimes lies in curbing global emissions, research from Woodwell Climate suggests that firefighting in boreal forests can be a successful emissions mitigation strategy. And a cost effective one too— perhaps as little as $13 per metric ton of carbon dioxide avoided, which puts it on par with other carbon mitigation solutions like onshore wind or utility-scale solar. It also has the added benefit of protecting communities from the health risk of wildfire smoke.
Rogers, along with Senior Science Policy Advisor, Dr. Peter Frumhoff, and Postdoctoral researcher Dr. Kayla Mathes have begun work in collaboration with the Yukon Flats National Wildlife Refuge in Alaska to pilot this solution as part of the Permafrost Pathways project. Yukon Flats is underlain by large tracts of particularly carbon-rich permafrost soils, making it a good candidate for fire suppression tactics to protect stored carbon.
The project will be the first of its kind— working with communities in and around the Refuge as well as US agencies to develop and test best practices around fighting boreal fires specifically to protect carbon. Broadening deployment of fire management could be one strategy to mitigate the worst effects of intensifying boreal fires, buying time we need to get global emissions in check.
When it comes to reversing climate change, trees are a big deal. Globally, forests absorb nearly 16 billion metric tonnes of carbon dioxide per year, and currently hold 861 gigatonnes of carbon in their branches, leaves, roots, and soils. This makes them a valuable global carbon sink, and makes preserving and maintaining healthy forests a vital strategy in combating climate change.
But not every forest absorbs and stores carbon in the same way, and the threats facing each are complex. A nuanced understanding of how carbon moves through forest ecosystems helps us build better strategies to protect them. Here’s how the world’s different forests help keep the world cool, and how we can help keep them standing.
Tropical forest carbon
Tropical rainforests are models of forest productivity. Trees use carbon in the process of photosynthesis, integrating it into their trunks, branches, leaves, and roots. When part or all of a tree dies and falls to the ground, it is consumed by microorganisms and carbon is released in the process of decay. In the heat and humidity of the tropics, vegetation grows so rapidly that decaying organic matter is almost immediately re-incorporated into new growth. Nearly all the carbon stored in tropical forests exists within the plants growing aboveground.
Studies estimate that tropical forests alone are responsible for holding back more than 1 degree C of atmospheric warming. 75% of that is due simply to the amount of carbon they store. The other 25% comes from the cooling effects of shading, pumping water into the atmosphere and creating clouds, and disrupting airflow.
In many tropical forest regions, there is a tension between forests and agricultural expansion. In the Amazon rainforest, land grabbing for commodity uses like cattle ranching or soy farming has advanced deforestation. Increasing protected forest areas and strengthening the rights of Indigenous communities to manage their own territories has proven effective at reducing deforestation and its associated emissions in Brazil. “Undesignated lands” have the highest levels of land grabbing and deforestation.
Fire has also become a growing threat to the Amazon in recent years, used as a tool to clear land by people illegally deforesting. When rainforests have been fragmented and degraded, their edges become drier and more susceptible to out-of-control burning, which weakens the forest even further. Enforcing and strengthening existing anti-deforestation laws are crucial to reduce carbon losses.
In Africa’s Congo rainforest, clearing is usually for small subsistence farms which, in aggregate, have a large effect on forest loss and degradation. Mobilizing finance to scale up agricultural intensification efforts and rural enterprise within communities, while implementing protection measures, can help decrease the rate of forest destruction. Forests and other intact natural landscapes such as wetlands and peatlands could be the focus of climate finance mechanisms that encourage sustainable landscape management initiatives.
Temperate forest carbon
Much of the forest carbon in the temperate zone is stored in the trees as well— particularly in areas where high rainfall supports the growth of dense forests that are resilient against disturbances like drought or disease. The temperate rainforests of the Northwestern United States, Chile, Australia, and New Zealand contain some of the largest and oldest trees in the world.
Two thirds of the total carbon sink in temperate forests can be attributed to the annual increase in “live biomass”, or the yearly growth of living trees within the forest. This makes the protection of mature and old-growth temperate forests paramount, since older forests add more carbon per year than younger ones and have much larger carbon stocks. Timber harvesting represents one of the most significant risks to the carbon stocks in temperate forests, particularly in the United States where 76% of mature and old growth forests go unprotected from logging. Fire and insects are also significant threats to temperate forests particularly in areas of low rainfall or periodic drought.
Maintaining the temperate forest sink means reducing the area of logging, by both removing the incentive to manage public forests for economic uses and by providing private forest owners with incentives to protect their land. Low-impact harvesting practices and better recycling of wood products can also help bring down carbon losses from temperate forests. In areas threatened by increasingly severe wildfires, reducing fuel loads especially near settlements can help protect lives and property.
Boreal forest carbon
In boreal forests, the real wealth of carbon is below the ground. In colder climates, the processes of decay that result in emissions tend to lag behind the process of photosynthesis which locks away carbon in organic matter. Over millennia, that imbalance has slowly built up a massive carbon pool in boreal soils. Decay is even further slowed in areas of permafrost, where the ground stays frozen nearly year round. It estimated that 80 to 90% of all carbon in boreal forests is stored belowground. The aboveground forest helps to protect belowground carbon from warming, thaw, decay, and erosion.
Wildfire— although a natural element in boreal forests— represents one of the greatest threats to boreal forest carbon. With increased temperatures, rising more than twice as fast in boreal forests compared to lower latitudes, and more frequent and long-lasting droughts, boreal forests are now experiencing more frequent and intense wildfires. The hotter and more often a stand of boreal forest catches fire, the deeper into the soil carbon pool the fire will burn, sending centuries-old carbon up in smoke in an instant. Logging of high-carbon primary forests is also a big issue in the boreal.
The number one protection for boreal forest carbon is reducing fossil fuel emissions. Only reversing climate change will bring boreal fires back to the historical levels these forests evolved with. In the meantime, active fire management in boreal forests offers a cost effective strategy to reduce emissions— studies found it could cost less than 13 dollars per ton of carbon dioxide emissions avoided. Strategies for fire management included both putting out fires that threaten large emissions, and controlled and cultural burning outside of the fire season to reduce the flammability of the landscape.
Fund for Climate Solutions awards five new grants
From floods to fire, the 2023 summer cohort of FCS projects seeks scalable climate solutions
The second round of 2023 Fund for Climate Solutions (FCS) awardees has been announced. The FCS advances innovative, solutions-oriented climate science through a competitive, internal, and cross-disciplinary funding process. Generous donor support has enabled us to raise more than $10 million towards the FCS, funding 58 research grants since the campaign’s launch in 2018. This latest cohort of grantees includes five projects working toward a range of scalable solutions to address climate impacts around the globe, from boreal and tropical forests, to heat-impacted cities, to much-discussed and still-struggling carbon markets.
Boreal fire management to protect permafrost and carbon
Lead PI: Brendan Rogers
Co-PI: Peter Frumhoff
As the climate changes, wildfires in boreal forests are intensifying and putting tremendous amounts of carbon at risk of accelerated release from trees and soils to the atmosphere. Motivated by previous Woodwell Climate research, the US Fish and Wildlife Service has recently set aside 1.6 million acres of the Yukon Flats National Wildlife Reserve in Alaska for enhanced fire management to protect carbon and permafrost, and has invited our collaboration to assess the potential and cost-effectiveness of boreal fire management as a to-date overlooked natural climate solution. This invitation is an unprecedented opportunity for actionable scientific research and timely policy impact. Supported by the FCS, the team will conduct the first-ever field study of boreal fire management for climate mitigation. Then, they will bring this work and its implications to decision makers and interest holders in Alaska and DC, positioning Woodwell Climate to expand the reach of this work within Alaska and, ultimately, to other boreal nations.
How climate change will exacerbate the vulnerability of people experiencing homelessness in Las Vegas
Lead PI: Christopher Schwalm
Climate change is exacerbating the vulnerability of people experiencing homelessness in Las Vegas, NV as they face increasing extreme heat risk on the street and flood risk inside stormwater infrastructure. In the city, people experiencing homelessness cope with extreme heat by sheltering in stormwater infrastructure. During the summer of 2022, Las Vegas experienced its wettest monsoon season in over 10 years, resulting in the loss of two lives due to flooded tunnels. This award will support our partnership with local homelessness organizations to develop ways to measure projected lethal heat days and extreme flooding, informing emergency evacuations and raising awareness of climate risk. Research Assistant Monica Caparas will be the on-site scientific lead, and serve as the point of contact for all local partnerships. Because the threat of climate change to people experiencing homelessness isn’t limited to Las Vegas, this work aims to advance climate justice by creating a replicable framework and best practices for establishing and nourishing working relationships with local communities, social service organizations, and government agencies.
Insights and lessons from 20 years of research on forest dynamics and agricultural sustainability in the Amazon
Lead PI: Ludmila Rattis
Co PIs: Marcia Macedo, Michael Coe, Linda Deegan, Christopher Neill, and Paulo Brando
Tanguro Field Station celebrates its 20th anniversary in 2024. Since its establishment by the Amazon Environmental Research Institute (IPAM Amazônia), 177 research papers have been published based on work conducted there. More than 215 students and journalists have participated in activities at Tanguro and produced theses, dissertations, policy briefs, and special content in prestigious journals and news outlets. While research at Tanguro has significantly advanced our understanding of tropical regions and continues to provide valuable ecological insights, there is a pressing need to synthesize past research. This award will support the preparation and publication of a synthesis paper that consolidates the findings and key insights from 20 years of research at Tanguro to facilitate a better understanding of the complex interdependencies within tropical ecosystems. This synthesis will also aid in developing a proposal to establish a Biological Integration Institute (BII-NSF) at Tanguro to promote collaboration, interdisciplinary approaches, and knowledge sharing among researchers, policymakers, and people affected by climate change and deforestation in the region.
Detecting post-fire recruitment failure and permanent forest loss
Lead PI: Arden Burrell
Co PIs: Yili Yang, Anna Talucci, and Brendan Rogers
Extensive field campaigns in the boreal forest and the western US have revealed that at an increasing number of study sites, tree species are failing to re-establish after fire destroys the stand. Such post-fire recruitment failure is increasing due to climate change, leading to a loss of both wildlife habitat and carbon storage, and reducing the area’s ability to provide ecosystem services. However, the large-scale extent of recruitment failure has not been studied—this is a key knowledge gap. The goal of this research is to perform a pilot study on existing sites in Yellowstone National Park to prove the feasibility of using remote sensing to detect recruitment failure, with the ultimate goal of obtaining further funding from US government agencies or private foundations. Bringing together Woodwell Climate scientists currently working on separate projects, including Permafrost Pathways, NASA ABoVE, and NSF Arctic System Science programs, this project will build on and synergize their existing research.
Advancing access to and applications of the Landscape Capital Index
Lead PI: Wayne Walker
Co-PIs: Seth Gorelik, Glenn Bush
Carbon markets could be a powerful mechanism for incentivizing natural climate solutions (NCS) while at the same time enhancing the well-being of land stewards and their communities. However, these markets have faced intense criticism for a lack of transparency and integrity. The project team has been working to develop the Landscape Capital Index (LCI), an independent, data-driven tool for assessing the potential of any tract of land to deliver climate mitigation, co-benefit, and conservation outcomes. With support from the FCS, the team will develop a web-based data platform prototype for beta testing and development into an interactive solution. This future state-of-the-art platform will enable access to and engagement with the LCI. The project team will also conduct targeted validation research to make sure the LCI performs well for strategic use cases in key geographic areas, with the goal of building user confidence in the data product’s integrity.
When boreal forests burn in the Far North of the U.S. and Canada, the whole world feels the impact. From communities evacuating from the blazes, to smoke clogging the air thousands of miles to the south, to the release of carbon emissions that accelerate climate change, boreal forest fires are a global issue.
Research from Woodwell Climate has recently expanded our understanding of the scope of impact that boreal fires have. A new paper, led by Research Associate Stefano Potter, quantified emissions associated with fires across most of boreal North America, shedding light on the dynamics of boreal fires and climate change. These four graphics explain:
1. Boreal fires threaten an important carbon sink.
Using a new higher-resolution dataset, generated as part of NASA’s Arctic-Boreal Vulnerability Experiment (ABoVE), Potter and his co-authors created a map of burned area across the boreal region. The researchers combined satellite imagery with observations from the largest database of boreal field studies, which allowed them to calculate emissions from both vegetation burned aboveground, and organic matter in the soils that burned belowground.
The results show that the overwhelming majority of carbon emissions from boreal fires—over 80% of total emissions in most places—comes from soils rather than trees. Despite the dramatic imagery of burning forests, most of the real damage is happening below the ground.
2. The true impact of boreal emissions is currently underestimated.
That finding on its own was not surprising to researchers, as the majority of carbon in boreal forests is stored below the ground. However, the fact that the overwhelming contribution of belowground carbon to fire emissions is being left out of existing global fire and climate models, means we’re drastically underestimating carbon emissions from Arctic and Boreal environments.
“A large reason for that is because the [existing] models are not detecting the belowground carbon combustion, which we are modeling directly,” says Potter.
Potter and the team working on the paper were able to accurately model belowground carbon loss because of their machine learning approach and the abundance of available field measurements in their dataset.
Accurately representing these numbers in global fire models is critical, because these models are used to plot climate trajectories and inform carbon budgets, which tell us how much we need to cut emissions to stay below temperature thresholds like 1.5 or 2 degrees C.
3. Boreal fires are becoming more intense.
It is becoming more urgent to get an accurate understanding of boreal emissions, because boreal fires are becoming larger, more frequent and more intense. Burned area has increased as fire seasons stretch longer, return intervals between fires shorten, and single ignitions can result in massive blazes that burn further and deeper and cause greater carbon loss.
In 2023, for example, while the number of ignitions has been lower than most years since the 1990s, burned area as of August has far surpassed any year in the past three decades.
4.Fire suppression can be a cost effective protection against carbon loss.
Ultimately, preventing carbon loss from boreal forest fires will require bringing down emissions from other sources and curbing warming to get fires back within historical levels. But preventing boreal forests from burning in the short term can offer a climate solution that could buy time to reduce other emissions.
A collaborative study between Woodwell Climate and the Union of Concerned Scientists, published in Science Advances, modeled the cost effectiveness of deploying fire suppression in boreal North America and found that actively combatting boreal fires could cost as little as 13 dollars per ton of CO2 emissions avoided—a cost on par with other carbon mitigation solutions like onshore wind or utility-scale solar. Informed by this data, the U.S. Fish and Wildlife Service has decided to start combating fires in Yukon Flats National Wildlife Refuge, not only when they present a threat to human health, but also with the intent of preventing significant carbon losses. Yukon Flats is underlain by large swaths of carbon-rich permafrost soils, at risk of thawing and combusting in deep-burning fires.
Deepening our understanding of the complex boreal system with further research will help inform additional strategies for bringing emissions under control, preventing devastating fires that threaten human health both regionally, and across the globe.
Canada’s fire season has barely started and it’s already on track to break records. So far, NOAA has documented more than 2,000 wildfires that have resulted in the forced evacuation of over 100,000 people across Canada. The most recent bout of fires burning in Ontario and Quebec has sent smoke southward into the Eastern U.S., causing record levels of air pollution in New York and warnings against outside activity as far south as Virginia.
Only a little over a month into the wildfire season, fires have already burned 13 times more land area than the 110-year average for this time of year, and they show no sign of stopping, according to Canadian publication The Star. Indigenous communities, some of whom live year-round in remote bush cabins, have been particularly harmed by the blazes.
According to Woodwell Climate Senior Scientist Dr. Jennifer Francis, the phenomenon of winds pushing smoke down to the northeastern U.S. has been linked to rapid Arctic warming caused by climate change.
In the upper atmosphere, a fast wind current called the jet stream flows from west to east in undulating waves, caused by the interaction of air masses with different temperatures and pressures, particularly between the Arctic and temperate latitudes.
As global temperatures have risen, the Arctic has warmed two to four times faster than the average global rate. Dr. Francis stated in an interview in the Boston Globe that the lessening of the temperature differences between the middle latitudes and the Arctic has slowed down the jet stream, which results in a more frequent occurrence of a wavy path.
Another factor contributing to the widespread smoke is an ongoing oceanic heat wave in the North Pacific Ocean. The blob of much-above-normal sea water tends to create a northward bulge in the jet stream, which creates a pattern that sends cooler air down to California and warm air northward into central Canada—resulting in the persistent heat wave there in recent weeks. Farther east, the jet stream then bends southward and brings the wildfire smoke down to the Northeast.
“Big waves in the jet stream tend to hang around a long time, and so the weather that they create is going to be very persistent,” Dr. Francis said. “If you are in the part of the wave in the jet stream that creates heat and drought, then you can expect it to last a long time and raise the risk of wildfire.”
The wildfires are also decimating North American and Canadian boreal forests, the latter of which holds 12 percent of the “world’s land-based carbon reserves,” according to the Audubon Society<./a> And three quarters of Canada’s woodlands and forests are in the boreal zone according to the Canadian government.
“The surface vegetation and the soil can dry out pretty dramatically given the right weather conditions. For this fuel, as we call it in fire science, it often just takes one single ignition source to generate a large wildfire,” said Woodwell Climate Associate Scientist Dr. Brendan Rogers.
As the climate continues to warm, Dr. Rogers said the weather conditions that lead to fuel drying and out-of-control wildfires also increase. This creates a feedback loop. Heat waves caused by greenhouse gas emissions increase the prevalence of wildfires. The fires in turn destroy these natural carbon sinks and, in turn, speed up climate change.
While the ultimate solution to breaking this feedback loop lies in reducing emissions and curbing climate change, Dr. Rogers and other researchers at Woodwell Climate have conducted research into fire suppression strategies that could help prevent large boreal fires from spreading and help keep carbon in the ground.
A study conducted in collaboration with Woodwell and other institutions found that suppressing fires early may be a cost-effective way to carbon mitigation. Woodwell Climate’s efforts also include mapping fires, using geospatial data and models to estimate carbon emissions across large scales, and looking at the interplay between fires and logging.
“Reducing boreal forest fires to near-historic levels and keeping carbon in the ground will require substantial investments. Nevertheless, these funds pale in comparison to the costs countries will face to cope with the growing health consequences exacerbated by worsening air quality and more frequent and intense climate impacts expected if emissions continue to rise unabated. Increased resources, flexibility, and carbon-focused fire management can also ensure wildlife, tourism, jobs, and many other facets of our society can persevere in a warming world,” Dr. Rogers said.