While natural and managed ecosystems like wetlands, forests, and agricultural fields often receive credit for emitting or absorbing carbon, there is an equally important yet largely overlooked contributor, acting within these ecosystems. Microbes, tiny single-celled organisms that live everywhere on Earth, are a powerhouse of carbon exchange, capable of absorbing and storing greenhouse gases like carbon dioxide and methane. Woodwell Climate researchers are studying both forests and fields to understand how natural microbial communities might be optimized into “climate heroes”, enhancing the carbon absorption capacity of natural and managed ecosystems.
One project leading the charge on this is Boreal Biosequester. Led by Associate Scientist Dr. Jennifer Watts and Senior Research Scientist Kathleen Savage along with collaborators at Arizona State University and the University of Maine Orono, this project is studying a particular class of microbe that “eats” methane, called methanotrophs.
Methane is 28 times as adept at trapping heat in the atmosphere as carbon dioxide. Today, atmospheric methane is around 2.6 times higher than during pre-industrial times. While some of these emissions are due to human sources, such as landfills and fossil fuels, around one-third of global methane emissions come from wetlands, and approximately 20-35% of wetlands are found in boreal and northern temperate forests. As a potent greenhouse gas, removal of atmospheric methane is a key natural climate solution that would help mitigate climate warming. The Boreal Biosequester team seeks to optimize the power of methane-eating microbes present in and on trees to turn methane-emitting landscapes into methane absorbers.
With funding from CarbonFix, a philanthropic organization dedicated to funding potential climate solutions, the Boreal Biosequester team has begun the first phase of the project: identifying microbial species present in the tree bark and foliage of Maine’s Howland Research Forest and studying their behavior. The researchers are investigating how trees in this northern forested wetland absorb and emit methane and how this capacity changes with environmental conditions like light, soil moisture, acidity, and temperature, to determine optimal environmental conditions for methane absorption
Much of this data is gathered from 30-meter-tall towers in the Howland Research Forest that measure methane and other gases being emitted and absorbed from this northern forest landscape. Howland boasts one of the longest global records of carbon dioxide and methane fluxes; these tower observations are paired with data collected directly from tree trunks and canopies to complete a comprehensive picture of microbial methane activity across the landscape.
“The different types of organisms that are in the trees absorbing methane have different sensitivities to temperature and how much nitrogen or sulfur or other [nutrients are] available to them,” says Watts. “What we really don’t know is: How do they live in the same space? Are there shared resources? We want to know what those preferences are.”
Boreal Biosequester team member Dr. Hinsby Cadillo-Quiroz, an ecology of microorganisms and ecosystems professor at Arizona State University, is leading the effort to isolate and study methanotrophs, sequencing their RNA and DNA to learn more about who they are and where they “like to live” in the forest.
“Plant surfaces host methanotrophs undoubtedly, although at low apparent density, so a critical question in this project is to figure out where, when, and how plant methanotrophs have the highest activity and potential to maximize their work,” says Cadillo-Quiroz. He is currently testing this question in sites around the world, including Howland.
The next phase of the Boreal Biosequester project will apply the knowledge gained from this early work to look at how the identified optimal environmental conditions can be “harnessed” to maximize methane absorption from trees using controlled greenhouse experiments.
“With greenhouse experiments, we can manipulate their environments and different tree species and then see how those microbes respond, so we can get a better sense of what those microbes like versus not, and how to optimize their behavior,” Savage says.
The final research phase of this project focuses on inoculating a forested wetland with “hardy” natural versions of these methane-eating microbes and tracing the response in landscape methane uptake. “If we can start to cultivate them successfully in the lab, we can start to select populations through natural selection,” Watts says. “We don’t want to do any direct genetic modification, but [we want to] grow the microbes that are a little bit more hardy.”
This work could yield natural climate solutions that are cost-effective and scalable for use by governments and land managers, and provide multiple benefits for carbon removal in restored or regenerating forests.
“If we understand what drives the natural activity of methanotrophs, it can inform the industry practices and plans,” Cadillo-Quiroz says.
Microbes could also be a powerful natural climate “ally” in other human-managed systems, like agricultural fields. Microbes in agricultural fields function as active climate engines by converting plant-derived carbon into stable carbon in soil, a process that could be optimized by using different land-management practices. According to Woodwell, soil microbial ecologist and biogeochemist, Dr. Taniya RoyChowdhury, properly managed croplands have the potential to become major carbon sinks.
“Global croplands have the theoretical capacity to sequester up to 2.6 gigatonnes of CO2 (carbon dioxide) annually,” RoyChowdhury says. “The research being pursued at Woodwell Climate is the critical link in the chain, providing the data needed to shift soil carbon storage from a ‘theoretical’ possibility into a ‘verifiable’ climate solution.”
RoyChowdhury is studying how regenerative agriculture practices like cover cropping could enhance a process called “necromass formation,” where carbon absorbed from the atmosphere by plants is consumed by soil microbes that then die. This carbon-rich “necromass” is then stored more permanently in the soil. This process is unique to microbes, so RoyChowdhury wants to understand how altering agricultural management practices, like cover cropping, could alter microbial activity in our favor.
“We’re trying to look at what the cover crop actually does to the microbial community. We’re genetically sequencing the microbial community in its totality and also looking at their functions,” says RoyChowdhury.
She says that working with microbes could also have co-benefits beyond carbon removal.
“Nature-based solutions [like microbes] are critical because they are the only tools we have that address the triple crisis of climate change, biodiversity loss, and food insecurity simultaneously,” says RoyChowdhury.
The other benefit of using natural climate solutions like microbes across ecosystems, RoyChowdhury says, is that once they are established, they manage themselves.
“Rightly managed natural systems are self-sustaining; once a wetland is restored or a forest is established, it continues to remove or sequester carbon and provide ecosystem services with minimal human intervention, making it a suitable strategy for long-term planetary stability,” RoyChowdhury says.
In a new paper, published today in Science, climate scientists from Woodwell Climate Research Center and leading research institutions across the world propose the creation of a new, global methane observation system to track methane emissions from natural ecosystems in near real-time and inform mitigation strategies and global climate policy.
Methane’s powerful near-term warming effects–80 times that of carbon dioxide–position methane mitigation as an urgent and important target for actionable global climate policy. Over the past decade, scientists and policymakers have made important strides in tracking methane emissions from anthropogenic sources, including fossil fuels, livestock, agriculture, waste management, and integrating those emissions in international climate policy and mitigation strategies. However, escalating methane emissions stemming from natural ecosystems driven by global temperature increases and climate feedbacks, such as tropical wetlands and thawing permafrost, make up more than one-third of the global methane budget, and yet remain largely omitted from global methane budgets and decisionmaking due to gaps in monitoring.
“As the planet warms, methane emissions from these natural systems, including permafrost, lakes, and wetlands, are rising quickly, bringing the potential for increased frequency and impact of extreme weather events like flooding, drought, wildfire, and extreme heat. Our ability to track and detect these emissions will be critical to informing solutions to the climate crisis,” said Dr. Jennifer Watts, Scientist at Woodwell Climate Research Center and lead author of this paper. “We are calling on national governments, international institutions, philanthropies, the private sector, and other partners to invest in adequate infrastructure to detect and monitor temperature-driven methane emissions from ecosystems to guide solutions that curb the impacts of methane and the climate crisis.”
This paper grew out of a multi-day convening of more than 30 leading methane scientists, modelers, and policy experts held in Aspen, Colorado in October 2025, organized through the Aspen Global Change Institute (AGCI). Co-chaired by scientists from Woodwell Climate Research Center/Permafrost Pathways, Stanford University, Arizona State University, and Spark Climate Solutions, the workshop brought together participants from universities, federal agencies, and research institutions spanning six continents to identify critical gaps in natural methane monitoring and chart a course for an integrated global observation system. The findings and recommendations in this paper reflect the collective expertise of that broader scientific community.
As global leaders in methane science, policy, and innovation prepare to gather at Methane 250 in Italy next week to chart a path forward for methane mitigation, this paper makes the case for investing in the development of an integrated Global Ecosystem Methane-Observation System to inform future Global Methane Pledges and action. Specifically, this system would close gaps in methane monitoring by securing and expanding ground-based networks of greenhouse gas observing towers, including flux towers, across underrepresented regions including rapidly thawing Arctic permafrost and wetlands in the tropics.
“Through Permafrost Pathways, we’ve seen firsthand how critical it is to fill the monitoring gaps in the Arctic, where thawing permafrost releases methane across landscapes so vast and varied that our current observation systems cannot fully capture them,” said paper co-lead and workshop co-organizer, Dr. Sue Natali, Senior Scientist at Woodwell Climate and lead of Permafrost Pathways. “This paper charts a path toward the integrated, global monitoring infrastructure we need to account for these emissions in climate policy before they outpace our ability to act.”
“Methane from natural systems is one of the biggest emerging climate risks,” said Dr. Danie Potocek, paper co-author and scientist at Spark Climate Solutions. “And right now, we simply don’t have the monitoring infrastructure to fully understand what we are up against. The global community has made real progress in building systems to track methane from human sources. Now we need to extend that to the rest of the methane challenge.”
When it comes to sucking carbon dioxide out of the atmosphere, trees and forests are well-known champions. But when it comes to sequestering methane, their role is much more complicated. Forest ecosystems sometimes absorb methane, other times they emit it — creating a complex exchange of gases that scientists are only beginning to understand. Boreal forests across Canada, Alaska, Scandinavia, and Russia can sometimes be methane sinks, but they’re also set to become major emitters as climate change accelerates.
That’s the challenge the Boreal Biosequester project is tackling. By deploying newly developed methane detecting chambers at Howland Research Forest in Maine, Woodwell Climate Associate Scientist Dr. Jennifer Watts and Senior Research Scientist Kathleen Savage, along with collaborators from Arizona State University and University of Maine Orono plan to measure methane flows on a granular level to understand which bacteria consume it and how they function across the ecosystem.
Once they’ve mapped these methane-munching microbes—called methanotrophs—across varying tree species, temperatures, and seasonal shifts, the researchers want to publish their findings so governments, land trusts and foresters can enhance the activity and presence of these climate superstars, transforming ecosystems from methane sources into sinks.
Why methane matters
Methane has been overlooked in climate discussions, which largely focus on carbon dioxide, but it’s 87 times more powerful at trapping heat over a 20 year period. Atmospheric levels of methane are now 2.6 times higher than pre-industrial levels—the highest they’ve been in 800,000 years. Crucially, methane emissions from boreal forests are expected to rise or even double as temperatures rise.
Natural environments, such as wetlands and forests, account for a large portion of global methane emissions, which is why finding nature-based solutions to bring down emissions is such an important area of research. Boreal Biosequester’s approach offers the chance to turn natural sources into sinks, while also providing co-benefits such as enhanced biodiversity, wildlife habitats, flood reduction, erosion prevention, and improved air quality.
“If the methanotrophs are there, why not learn to work with them as effectively as possible?” says Watts. “If we were to work with human technology to reduce methane, you’d have to build something energy-intensive. This is a passive way to work with the forest sustainably. If we leave a forest to grow or regenerate, or if we afforest, we can both draw down CO2 and, we hope, consume methane.”
The genesis of the project
Watts and Savage were initially looking at methane sources and sinks for the US National Science Foundation. At first, they focused on soils, which were at the time considered the primary drivers of whether forests were sources or sinks. Then a groundbreaking paper revealed trees’ crucial role in methane uptake. With microbial ecologist Dr. Hinsby Cadillo-Quiroz from Arizona State University, they decided to study methane fluxes around tree trunks and canopies as well as in the soil, and sought funding from CarbonFix to carry out this study.
“When we looked at the canopy level, we could see net consumption, but soil data were all over the place,” Watts explains. “The data showed something important happening between the soils and treetops.”
The world of methanotrophs on plant surfaces is largely uncharted. The team will isolate and study these bacteria in labs while measuring methane consumption across soils, trunks, and canopies through different seasons and climates.
“We’re really the explorers venturing into this new micro-universe,” says Watts. “We know there are microbes out there, we just need to get to know them.”
Only in the last 15 years could methane gas be measured accurately at this scale. The team is uniquely positioned at Howland Forest, which has rare historical methane flux data from eddy covariance towers (structures measuring the exchange of gases) dating to 2011, plus access to both pristine and harvested forest areas for direct comparison.
The Method
CarbonFix’s grant will be used for the first phase to map methanotroph behavior and measuring fluxes across forest layers across the course of a year. Once they’ve secured additional funding, the team will identify optimal conditions for methane consumption across different tree species and environments. Next, they’ll test hypotheses in greenhouse settings, demonstrating how specific tree species can convert methane-emitting wetlands into methane-consuming ecosystems.
Finally, they’ll share findings through reports and presentations targeting governments, land trusts, foresters, and carbon markets to implement these practices in forest management.
Potential impact
For now, the team will focus on working out how methanotrophs function, and the conditions in which they thrive.
“A tiny creature, like a methanotroph, can influence a tree in many ways: it can fix nitrogen, it can clean metabolites. But the true beauty of this partnership is that a single tree could host methanotrophs in many ways and a thousand trees can host methanotrophs in a million ways. We just need to figure out how to channel this partnership to remove many tons of methane molecules. Achieving that would be a major breakthrough to help gain time against climate change,” says Cadillo-Quiroz.
The findings may extend beyond forests to landfills, agriculture, logging, or fire-damaged areas — countless applications where understanding and influencing methane fluxes through bacteria could prove transformative.
What’s more, if the team’s findings show how methanotrophs can be inoculated into new forests, they could become part of every new reforestation project.
Reforestation is urgently needed: between 2001-2023, Canada, Alaska, and the Northern US lost over 70 million hectares of forest — three times the UK’s landmass — from fire and harvest. Most of these wet soil areas are net methane emitters. Reforesting and inoculating them with methanotrophs could create carbon and methane sequestration superheroes. The team estimates targeted afforestation could remove over 10 million metric tons of methane — reducing 30-40% of high-latitude methane budgets while simultaneously sequestering CO2.
But for now, there’s lots of work to be done. The team of four are rolling up their sleeves for fieldwork and lab analysis.
“At minimum, it will be fascinating data filling knowledge gaps about methane uptake,” says Savage. “If we can remove methane short-term, we have leeway to address more challenging CO2 elements requiring extensive work.”
Watts adds: “Our group is always thinking about how what we do now will impact society later. I’m excited to develop methodologies that we can share worldwide, creating community transformation for people across the planet.”
Summers in the Arctic-boreal region are becoming increasingly defined by fire. In 2023, Canada endured its worst wildfire season in history, with nearly 200,000 Canadians displaced. Fast forward to summer 2025, and the country faces its second-worst wildfire season on record, with 470 outbreaks deemed “out of control” by August. Siberia and Alaska are also confronting active fire seasons.
For Arctic communities, the physical impacts of smoke exposure, the toll of evacuations and destruction, and the threats to cultural traditions compound the danger of extreme fires. But Indigenous science and cultural traditions offer a path towards justice and resilience.
Climate change and colonial histories fuel the fire
Climate change has created hotter and drier conditions in the north, increasing the frequency and intensity of Arctic-boreal wildfires. These wildfires amplify global warming, creating a feedback loop by burning deep into permafrost, a carbon-rich soil, and releasing stored carbon dioxide and methane into the atmosphere. A recent study led by Permafrost Pathways researchers found that wildfire has contributed to the Arctic’s shift from a net absorber to a net emitter of carbon. That increase in emissions in turn fuels even more fires. Between 2003 and 2023, the Arctic-boreal region saw a sevenfold increase in extreme wildfires.
“Things have really changed in our traditional territories,” said Woodwell Climate’s Adaptation Specialist, Brooke Woods. Woods is a Tribal member from Rampart, Alaska, and she currently lives in Fairbanks, Alaska. “We had two fires close to Rampart this summer. We’ve had back-to-back fires over the past three summers. Growing up, I don’t ever recall back-to-back wildfires surrounding our communities.”
The increase is also due, in part, to increased lightning strikes, which are occurring more frequently as warming temperatures further destabilize atmospheric conditions, leading to more storms that produce lightning.
“Our summers are drier and we’re having more severe heat events as well as more intense lightning and thunderstorms now, too,” said Woods. “When we had the fire in Rampart, in the midst of this wildfire, one of the storms actually produced 1600 lightning strikes across Alaska.”
The history of colonialism in North America has also played a role in today’s extreme wildfire regimes. For millennia, Indigenous Peoples across the Arctic practiced cultural burning—using small, controlled fires to manage the land, reduce dry fuel buildup, and prevent large, catastrophic wildfires. These practices not only protected ecosystems but also supported biodiversity and were deeply rooted in cultural knowledge and tradition. However, colonization disrupted these systems as Indigenous communities were forcibly removed from their lands, and cultural burning was often banned and criminalized altogether.
“Elders risked jail time for burning,” Dr. Amy Cardinal Christianson told Chatelaine Magazine. Christianson is a Metis wildfire expert and Policy Advisor for the Indigenous Leadership Initiative who co-hosts the podcast Good Fire and serves on the board of the International Association of Wildland Fire. “That’s how badly they knew that the land needed to burn.”
This erasure, combined with colonial fire suppression tactics, has led to the accumulation of flammable undergrowth that makes the land more vulnerable to intense and widespread fires.
Smoke, displacement, and cultural survival
Increasingly active Arctic-boreal wildfires are not just environmental disasters, they’re also cultural and human crises.
Wildfire smoke—which can contain soot and high levels of mercury— threatens the health of Arctic communities and can put vulnerable groups, like elders, young children, and those with pre-existing health conditions, at prolonged risk well after the fires have gone out.
“In my baby’s first year of life in 2023, we had such bad air quality [in Fairbanks]. It impacted his respiratory system, and it was just so hard for him to be able to nurse,” said Woods. “I was even considering driving 300 miles to the next urban area to get him to clean, healthy air because there was also a fire in Rampart. It impacted our safety in both of the places that we call home.”
The mental toll of wildfires can also be just as devastating as the physical impacts, as communities must navigate evacuation logistics, loss, and displacement with very little governmental support.
“Communities are thinking about how the wildfire crisis is real—it’s driven them from their home and maybe destroyed their home—they’re thinking ‘what else am I going to lose’?” said Edward Alexander, Senior Arctic Lead at the Woodwell Climate Research Center, Chair of Gwich’in Council International, and Co-Chair of the Arctic Council’s Expert Group on Wildland Fire. “Then, becoming unhoused… people lose their jobs, their businesses, or their investments. They lose forward momentum in their life.”
In addition, evacuation is far more complicated in the Arctic. Many remote communities and villages in Alaska and Canada either have only one main road or aren’t connected to road systems at all, making them accessible only by plane or boat, which presents a logistical and financial challenge for mass evacuation. The combined impacts of smoke, heat, and economic insecurity can also present impossible choices.
“If you look at not only the health disparities but your income, what can you afford to keep yourself healthy?” said Woods. “Can you afford air filters for your home? Can you afford and have access to air conditioners with filters? Because not only are you battling the smoke, but you’re also battling this heat. So just navigating those at different income levels can be very complex.”
Fire doesn’t just destroy infrastructure and threaten health and well-being, it also disrupts Indigenous ways of life, cultural connections to land, intergenerational knowledge sharing, language revitalization, and cultural history tied to specific places like hunting trails, fish camps, and seasonal migration.
“When we were still able to subsistence fish in Alaska, and had wildfires at the same time, there were community members in Rampart that were not able to meet all of their subsistence needs due to wildfires,” Woods said.
Traditional solutions for modern problems: A return to cultural burning
In Good Fire, Christianson discusses ways to restore the modern world’s broken relationship with fire and the need to integrate systems that not only respond appropriately but are also proactive and predicated on Indigenous Knowledge and expertise. This is where cultural burning offers a way forward—a way to view fire not as a threat, but as a critical tool for keeping land healthy and communities safe.
The First Nations Emergency Services Society (FNESS) and the Indigenous Leadership Initiative (ILI) recently released the “Create a Cultural Burn Pathway” workbook to support Indigenous communities in creating cultural burn programs to reduce wildfire risk and maintain healthy connections to the land.
“Fire doesn’t have to be scary,” said Christianson in a video produced by the Indigenous Leadership Initiative. “It doesn’t have to be something we live in fear of every summer. We can have a better relationship with fire that can have really important benefits.”
Traditional burning is a culturally grounded, community-empowered, and ecologically practical approach to managing and mitigating wildfire risk in the North, born from generations of Traditional Ecological Knowledge. Unlike conventional fire suppression, which often seeks to eliminate fire altogether, cultural burning is a proactive, place-based practice rooted in Indigenous governance, values, and ecological understanding. These approaches aren’t about fighting fire—they’re about embracing it to foster sovereignty, revitalize knowledge, and deepen connection to the land.
Beyond the health of the land and forests, cultural fire also contributes to cultural resilience and maintains Indigenous connections to land and community. Cultural burns ensure practices are guided by traditional protocols and adapted to local ecosystems. Community members, including youth, are involved—passing knowledge between generations and restoring cultural roles that were disrupted by colonization.
Which is why, according to Alexander, placing the emphasis on the health of the forest, ecosystems, and community overall, rather than on controlling fire, should be the real goal.
“We should be thinking a little differently,” Alexander said. “Cultural fire is a tool, but fire is not the emphasis. It’s the health of the forest, it’s the health of the land, it’s the health of the animals and birds, it’s the health of our peoples and communities. That’s the emphasis.”
From ‘wildfire to mildfire,’ Indigenous fire stewardship as a path forward
Cultural burning is just one part of the solution, which will involve moving away from colonial fire suppression methods altogether and supporting Indigenous-led fire stewardship models with meaningful changes in policy and funding. Woods says she’d like to see Indigenous-led fire programs represented as part of a broader recognition of Indigenous sovereignty in the North.
“I’d like to see more local people leading the work rather than just renting out their equipment or hiring them as boat captains,” Woods said. There are more opportunities for Indigenous People to help their own communities. I feel there’s always time to course correct and really acknowledge and honor the 229 Tribes of Alaska and their practices that have maintained very healthy land and ecosystems for so long.”
In Alaska, Indigenous-led wildfire initiatives—like the U.S. Bureau of Land Management (BLM) Emergency Firefighter (EFF) program—create opportunities for local members of Alaska Native communities to join crews and integrate their traditional knowledge and expertise of the land to help keep their communities safe. In Canada, Fire Guardian programs—which Dr. Christianson has long been advocating for—aim to get good fire back on the land through Indigenous stewardship and traditional practices.
Alexander says he hopes recognizing cultural burning and other forms of Indigenous Knowledge as legitimate science will help prioritize them in land management.
“It’s critically important science that we need to help us manage the wildland fire crisis in the circumpolar north,” said Alexander.
Alexander imagines a future where wildfire becomes mildfire. Where communities in the north are adequately resourced and wildfire management becomes proactive and rooted in Indigenous Knowledge and expertise, while prioritizing and supporting sovereignty.
“Indigenous fire management looks like a vibrant landscape where you don’t have severe wildland fire, but you have increased biodiversity, where the vegetation is more nutritious for the plants and animals, and that permafrost and other hugely important resources are protected,” Alexander said. “I also think that it’s an integral part of respecting the sovereignty of Indigenous Peoples, of respecting the self-determination of Indigenous Peoples to manage our territories how we see fit, and I think that it’s a really critical approach that we need to all be listening to. Our collective future really depends on it.”
In the northern ecosystems of the Alaskan boreal forest and tundra, wildfire is a natural – and even necessary – process. But as temperatures rapidly warm, wildfire frequency and severity in the state are breaking historical records.
Scientists at Woodwell Climate Research Center are studying the effects of these increased fires on the ecosystem. In a study published earlier this year, a research team led by Research Scientist Dr. Scott Zolkos examined the relationship between northern wildfires and one concerning byproduct of them: mercury pollution.
Higher temperatures, more wildfires, more pollution
In the last 25 years, Alaska has experienced some of the worst fire seasons on record. One of the reasons behind this is that climate change is hitting the north harder than other regions.
Northern latitudes, including the Arctic and boreal regions, are warming three to four times faster than the rest of the planet. As warmer temperatures melt snow earlier in the year and dry out soil and vegetation, the fire season lengthens and intensifies. According to Woodwell scientists, 2024 was the second-highest year for wildfire emissions north of the Arctic Circle.
“It’s really sort of a new phenomenon, the level of burning we’re seeing in the tundra,” Dr. Brendan Rogers, Senior Scientist, says.
Increasing fires means increasing air, water, and ecosystem pollution from the byproducts of burning vegetation and soils. Mercury is a toxic pollutant in wildfire smoke, but there is sparse research on mercury release from northern peatland wildfires which means scientists don’t yet have a great understanding of how increasing northern wildfire activity could counteract efforts to curtail human-caused mercury release. To understand these impacts, Zolkos and collaborators studied areas of the Yukon-Kuskokwim (YK) Delta in southwestern Alaska— a peatland environment that burned in 2015. The summer of 2015 made history as one of Alaska’s worst fire seasons, with over 5 million acres of land burned.
The research team used peatland soil samples that were collected between 2016 and 2018 by undergraduate participants of The Polaris Project to measure mercury. They then used the new mercury data together with organic carbon and burn depth measurements from another recent study to develop models that predicted mercury emissions from the 2015 wildfires.
Measuring mercury release
Mercury continuously cycles through the environment in air, water and soil, often changing between liquid and gaseous forms. It enters the atmosphere as emissions from human activities like the burning of fossil fuels and natural processes like wildfires and volcanoes. High levels of mercury can accumulate in the ground when vegetation takes up mercury from the atmosphere, then decomposes and deposits it into the soil. In northern peatlands, mercury has been accumulating with organic matter for thousands of years.
Mercury emissions occur when wildfire burns organic matter in soil and releases mercury that is bound to it back into the atmosphere. With increased temperatures and wildfire activity, the stabilization accumulation of mercury in the soil is threatened – and so is air quality.
“There are huge mercury stores in northern peatlands,” Zolkos says. “If peatlands burn more, it could potentially offset global efforts to reduce human mercury release into the environment.”
Zolkos and collaborators found that levels of mercury in peat in the YK Delta were similar to those in peatlands elsewhere in the north. Using an atmospheric chemical transport model developed by collaborators, the researchers also found that mercury deposition within 10 kilometers of wildfire sites was two times higher than normal, even though the majority of emissions from the fire traveled beyond Alaska.
With this information, Zolkos believes that increasing fire activity has the potential to unlock large amounts of soil-bound mercury in the North. The challenge now is figuring out exactly how much mercury is being released and where it ends up.
As a step to understanding this, Zolkos is leading a pilot project to develop an atmospheric mercury monitoring network across wildfire-susceptible peatlands in Alaska and Canada. Twenty-six air samplers, which collect mercury molecules in the air, were deployed at seven sites in Arctic-boreal peatlands across Alaska and Canada during the summers of 2024 and 2025. After the 2025 summer season is complete, the samplers will be sent to a lab at Harvard University, where Zolkos will measure their mercury content.
“Our goal is to work with collaborators to deploy these simple and cost-effective samplers that capture mercury in the atmosphere,” Zolkos says. “And from that, we can back-calculate the concentration of mercury in the air to understand wildfire impacts.”
By studying trends, Zolkos can compare levels of mercury in the air in areas affected and not affected by wildfire. And with added contextual data, scientists can model how much mercury might have been released from the soil and vegetation by wildfire.
Understanding wildfire impacts on air quality
In addition to containing mercury, wildfire smoke also emits particulate matter (PM2.5). PM2.5 refers to particles that are smaller than 2.5 micrometers in diameter – thirty times smaller than the average human hair. When breathed in, they can affect the heart and lungs and cause a variety of health problems, including aggravated asthma, decreased lung function, and increased respiratory symptoms.
Together with collaborators from the Permafrost Pathways project, Zolkos is also collaborating with Alaska Native communities to install PurpleAir sensors, a system of particulate matter monitors, to support tribally-led wildfire air pollution monitoring. This project helps to address monitoring needs in Alaska, where nearly 90% of rural communities reached or exceeded unhealthy levels of PM2.5 at least once due to wildfire in the last two decades.
“It’s a really great opportunity to work together with Alaskan Native communities and also to share knowledge, learn from them, and try and help them with any needs that they have for environmental monitoring,” Zolkos says.
So far, particulate matter sensors have been deployed in Pond Inlet in Nunavut, Canada, Churchill in Manitoba, Canada, and Akiachak, Alaska.
“The complex impacts of wildfire on Arctic and global communities is not something that can be solved by taking a measurement and seeing a number alone. These climate health impacts require a more holistic way of thinking and doing research” Dr. Sue Natali, Senior Scientist and lead of the Permafrost Pathways project, says. “What gives me hope is that the Western scientific community is now listening and hearing more from Indigenous partners to co-produce research to support climate resilient communities,”
At Fort Stewart-Hunter Army Airfield in Georgia, dozens of people in uniform position themselves along the edge of a pine stand as multiple aircraft approach overhead and a helicopter starts dropping incendiary devices into the forest in front of them. This may sound like a military training exercise but it is not. It is the NASA FireSense campaign, co-led in partnership with the Department of Defense and the U.S. Forest Service, a carefully planned and coordinated set of scientific experiments being used to better understand wildfires.
As wildfires get more frequent, intense, and destructive due to human activity, scientists are coming up with new and creative ways to study them. This is what brought me to this collaborative project at Fort Stewart in March 2025 for a week of prescribed burns and intensive wildfire research.
I’m an ecologist at Woodwell Climate Research Center working to understand how climate change is altering wildfires in boreal forests and the Arctic. I improve ecosystem models— computer software programs that simulate how ecosystems work— to better predict wildfire under a changing climate. This requires a holistic understanding of wildfires: from the way plants grow and produce fuels, to the weather that leads to fires, to how fires spread and grow. For me, getting out in the field is an important way to confirm that my computer simulations are behaving like real fires.
Wildfires can be a difficult and dangerous environment in which to do research. For this reason, wildfire research is sometimes done during prescribed fires. Prescribed or controlled burns are lit by trained professionals to reduce the buildup of natural fuels and to benefit plants and wildlife, especially in ecosystems that historically had regular wildfires. Fort Stewart has one of the largest prescribed fire programs in the United States, burning around 115 thousand acres every year. Burns are performed both to protect soldiers from wildfires that can easily start during military training exercises, as well as to manage the base’s pine forests for the recovery of several threatened and endangered species including the red-cockaded woodpecker and the smooth coneflower. This makes it a great location to do research. Unlike wildfires, controlled burns allow researchers to know exactly when and where a fire will occur, giving them time to plan safe research projects.
This most recent experimental burn campaign represents a new level of cooperative effort to study wildland fire at all stages. While the Environment and Natural Resources Division Forestry Branch at Fort Stewart conducted the prescribed burns, researchers from NASA and seven DoD Strategic Environmental Research and Development (SERDP) funded research projects deployed weather stations, fire sensors, cameras, and emberometers on the ground. NASA flew three aircraft overhead with advanced sensors aimed at the fire below and a radar truck monitored the smoke plume. Fuels were measured with LIDAR scanners before and after the fires to detect what burned. During the fire, fuel moisture was measured. The ability to study conditions before, during, and after a fire gives a more complete picture of fire behavior compared to a wildfire where researchers are often limited to data gathered after the threat of the fire has passed.
Working together like this makes for more than just good science, it also builds community. Like all scientists, wildfire researchers tend to be specialized, with some studying fuels, while others study smoke, or the energy produced by the flames. Bringing these people together allows them to share ideas, discuss problems, and learn new experimental techniques. These connections and conversations are what spark new ideas and collaborations that push science forward. For me this was a valuable opportunity to meet other researchers, discuss ideas, and to learn how to perform experiments safely in a fire, something that could help me improve my wildfire models in the future.
The FireSense campaign at Fort Stewart went off without a hitch. The data collected during the campaign will take many months to analyze, but the hope is that this campaign will act as a model for a new era of cooperative wildfire research. Planning for another campaign next year in Florida is already under way and in the meantime I’ve returned to my lab to refine my code and apply what I’ve learned in preparation for the next fire.
When I started at Woodwell Climate, I had very little personal or professional experience with boreal wildfire. I was a forest ecologist drawn to this space by the urgency of the climate crisis and the understanding that northern ecosystems are some of the most threatened and critical to protect from a global perspective. More severe and frequent wildfires from extreme warming are burning deeper into the soil, releasing ancient carbon and accelerating permafrost thaw. Still largely unaccounted for in global climate models, these carbon emissions from wildfire and wildfire-induced permafrost thaw could eat up as much as 10% of the remaining global carbon budget. More boreal wildfire means greater impacts of climate change, which means more boreal wildfire. But when I joined the boreal fire management team at Woodwell, the global picture was the extent of my perspective.
This past June, under a haze of wildfire smoke with visible fires burning across the landscape, Woodwell Climate’s fire management team made our way back to Fort Yukon, Alaska. Situated in Yukon Flats National Wildlife Refuge at the confluence of the Yukon and Porcupine Rivers, this region is home to Gwich’in Athabascan people who have been living and stewarding fire on these lands for millennia. Our time there was brief, but it was enough to leave us humbled by the reality that the heart of the wildfire story—both the impacts and the solutions—lie in communities like Fort Yukon.
We listened to community members and elders tell stories about fire, water, plants, and animals, all of which centered around observations of profound change over the past generation. As we shared fire history maps at the Gwichyaa Zhee Giwch’in tribal government office, we were gently reminded that their knowledge of changing wildfire patterns long preceded scientists like us bringing western data to their village. We learned that fire’s impact on critical ecosystems also affects culture, economic stability, subsistence, and traditional ways of life. Increasing smoke exposure threatens the health of community members, particularly elders, and makes the subsistence lifestyle harder and more dangerous. A spin on the phrase “wildland urban interface,” Woodwell’s Senior Arctic Lead Edward Alexander coined the phrase “wildland cultural interface,” which brilliantly captures the reality that these fire-prone landscapes, culture, and community are intertwined in tangible and emotional ways for the Gwich’in people.
“There’s too much fire now” was a common phrase we heard from people in Fort Yukon. Jimmy Fox, the former Yukon Flats National Wildlife Refuge (YFNWR) manager had been hearing this from community members for a long time, along with deep concerns about the loss of “yedoma” permafrost, a type of vulnerable permafrost with high ice and carbon content widespread throughout the Yukon Flats. With the idea originating from a sharing circle with Gwich’in Council International, in 2023 Jimmy enacted a pilot project to enhance the fire suppression policy of 1.6 million acres of yedoma land on the Yukon Flats to explicitly protect carbon and climate, the first of its kind in fire management policy. He was motivated by both the massive amount of carbon at risk of being emitted by wildfire and the increasing threats to this “wildland cultural interface” for communities on the Yukon Flats.
Ever since I met Jimmy, I have been impressed by his determination to use his agency to enact powerful climate solutions. Jimmy was also inspired by a presentation from my postdoctoral predecessor, Dr. Carly Phillips, who spoke to the fire management community about her research showing that fire suppression could be a cost-efficient way to keep these massive, ancient stores of carbon in the ground. Our current research is now focused on expanding this analysis to explicitly quantify the carbon that would be saved by targeted, early-action fire suppression strategies on yedoma permafrost landscapes. This pilot project continues to show the fire management community that boreal fire suppression, if done with intention and proper input from local communities, can be a climate solution that meets the urgency of this moment.
“Suppression” can be a contentious word in fire management spaces. Over-suppression has led to fuel build up and increased flammability in the lower 48. But these northern boreal forests in Alaska and Canada are different. These forests do not have the same history of over-suppression, and current research suggests that the impacts of climate change are the overwhelming driver of increased fire frequency and severity. That said, fire is still a natural and important process for boreal forests. The goal with using fire suppression as a climate solution is never to eliminate fire from the landscape, but rather bring fires back to historical or pre-climate change levels. And perhaps most importantly, suppression is only one piece of the solution. The ultimate vision is for a diverse set of fire management strategies, with a particular focus on the revitalization of Indigenous fire stewardship and cultural burning, to cultivate a healthier relationship between fire and the landscape.
The boreal wildfire problem is dire from the global to local level. But as I have participated in socializing this work to scientists, managers, and community leaders over the past year, from Fort Yukon, Alaska to Capitol Hill, I see growing enthusiasm for solutions that is not as widely publicized as the crisis itself. I see a vision of Woodwell Climate contributing to a transformation in boreal fire management that has already begun in Indigenous communities, one that integrates Indigenous knowledge and community-centered values with rigorous science, and ends with real reductions in global carbon emissions. Let’s begin.
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.
