Burnt trees in a forest after a wildfire. Photo Credit: Engin Akyurty / Pexels
Forests are among the planet’s most important natural carbon sinks, storing vast amounts of carbon that would otherwise contribute to climate change. As a result, many climate policies and carbon-credit programs depend on forests’ ability to absorb and retain carbon over long periods of time.
However, that storage is not guaranteed. Wildfires, drought and insect outbreaks can kill trees and release their stored carbon back into the atmosphere. As climate change increases the frequency and severity of these disturbances in many regions, researchers are raising concerns about whether current carbon-credit systems fully account for the risks.
A new study published in Nature by researchers from the University of Utah, UC Santa Barbara and several partner institutions found that carbon markets may be underestimating the likelihood of future carbon losses in U.S. forests, particularly across the American West.
Co-author Dr. Anna Trugman, a forest ecologist and principal investigator at UC Santa Barbara’s Marine Science Institute, said the findings highlight the importance of considering climate-related disturbances when using forests as part of long-term climate strategies.
Getting to net zero emissions will take a portfolio of solutions, but in many regions, escalating disturbance associated with climate change makes it riskier to count on forests to sequester carbon.
The researchers sought to determine which forests are most vulnerable to future carbon losses and whether existing carbon-credit programs adequately account for those risks. To do so, they combined forest inventory data, satellite observations and machine-learning techniques to map the probability of carbon reversals caused by wildfire, drought and insect outbreaks over the next century.
Their analysis revealed significant differences between risk estimates based on historical conditions and projections that incorporate climate change. Wildfire emerged as the largest climate-sensitive threat to the long-term durability of forest carbon storage. In some areas of Idaho, Southern California, Arizona and New Mexico, the likelihood of experiencing a major carbon loss from wildfire over the next 100 years exceeded 80%.
The study also evaluated “buffer pools,” reserves of carbon credits set aside to compensate for unexpected losses when forests burn or experience widespread tree mortality. Researchers found that buffer pools used in projects regulated by the California Air Resources Board, one of the nation’s largest carbon-credit programs, are generally too small to cover projected risks over a 100-year period. On average, the study suggests these reserves would need to be several times larger to fully account for expected future losses.
The findings do not suggest that forest-based climate solutions should be abandoned. Instead, the authors argue that carbon-credit programs can be strengthened by incorporating the best available science on climate risks. More accurate assessments could help guide conservation and restoration efforts toward forests that are more likely to retain carbon over the long term.
In addition to the study, the researchers are making interactive tools available to help land managers and policymakers identify areas where forest carbon projects may be most resilient under future climate conditions.
The authors say that improving how climate risks are incorporated into carbon markets could help ensure that forest carbon projects deliver meaningful and lasting climate benefits in the decades ahead.
Adapted from original reporting by Harrison Tasoff, “Carbon markets underestimate the risks U.S. forests face from climate change,” The Current, UC Santa Barbara, 2026.