Long a bulwark in the battle against climate change, northern forests absorb a significant amount of the world’s carbon dioxide.

But research out of Boston University suggests that current computer-based models used to predict the Earth’s changing climate have underestimated the impact forest fires and timber harvests have on the world’s northernmost forests to capture and store atmospheric carbon.

Mark Friedl, an environmental Earth scientist and professor at the College of Arts & Sciences, along with PhD student Jonathan Wang, arrived at this finding by studying 30 years of data on the world’s forests with the help of cutting-edge satellite imaging. “Current Earth systems models appear to be misrepresenting a big chunk of the global biosphere,” says Friedl, who also directs BU’s Center for Remote Sensing.

Friedl and Wang developed a method to glean richer information through NASA’s ICESat mission, a satellite carrying laser technology that can detect the height of vegetation within a forest, not just the cover. The researchers saw that northernmost forests have been losing more biomass than expected due to increasingly frequent and extensive forest fires, and that the hardwoods replacing the lost conifers were less resilient. Their study, published in Nature Climate Change in April 2021, underscores the threat that the global climate crisis poses for the far north—home to the largest forest biome on the planet—and makes efforts to reduce carbon emissions all the more urgent.

“When big chunks of real estate in places like California go up in flames, that gets our attention,” Friedl says. “But northern forests, which hold some of the largest stocks of carbon in the world, are being impacted by fires more than we realized until now.”