Wildfires in the boreal forests of Alaska, Canada, Scandinavia, and Russia may be releasing more carbon into the atmosphere than previously estimated, according to a UC Berkeley-led study published on Feb. 27.
The findings are significant because they suggest that current models do not fully capture the climate impact of these northern fires. The research highlights how wildfires can burn deep into peat-rich soils that have stored carbon for centuries or even millennia, potentially accelerating climate change.
The study’s lead author Johan Eckdahl said, “Many of the fires that matter most for the climate don’t look dramatic from space. Peatlands and organic soils can smolder for weeks to years, releasing enormous amounts of ancient carbon.” Eckdahl and his team reconstructed emissions from 324 wildfires in Sweden by combining national forest data with field measurements. They found that while satellite-based models overestimated emissions from visible high-intensity fires in regions like Gävleborg county, they severely underestimated emissions—by up to a factor of 14—from less visible low-intensity fires burning through thick soil layers in Dalarna county.
Eckdahl said, “Sweden is a very large country, but it’s quite small compared to Siberia and Canada. We may be severely underestimating the impact of the recent extreme fire seasons in these regions.” He explained that collecting accurate soil data is challenging: “Once you’re out there, it’s a simple task — just dig some holes — but the hard part is getting to the sites…in Siberia, I hear it’s a real trek.”
The Rausser College of Natural Resources at UC Berkeley supports this kind of research through donor contributions that enhance undergraduate opportunities and student scholarships according to its official website. The college advances societal well-being through research on environmental sustainability and human health improvements according to its official website, and features facilities such as greenhouses and specialized growth chambers for plant science education according to its official website.
Rausser College is recognized as a leader nationally and globally in natural and social sciences according to its official website, functions as an integral part of UC Berkeley within the University of California system according to its official website, and focuses on interdisciplinary approaches involving biological, ecological, economic, and social sciences for addressing environmental challenges according to its official website.
Looking ahead, Eckdahl will work with colleagues across UC Berkeley as part of the Western Fire & Forest Collaborative to adapt their approach for studying wildfire impacts in western U.S. forests. He said: “Forests in the Lower 48 and those far up north may look very different, but they share the common currency of carbon…By improving our understanding of how this element flows between land and atmosphere we can better anticipate future fire regimes…and design smarter strategies to reduce climate risks on society.”
