Trees absorb 30 percent of the carbon humans pump into the atmosphere through the burning of fossil fuels, making forests key players in the fight against climate change.
But a recent study involving a Woods Hole scientist found that cold-climate forests in Canada and Alaska are struggling to soak up excess carbon. Scientists now worry about how these ecosystems will keep pace with just how much fossil fuel is burned each year, and manage carbon uptake as they become hotter, drier, and more prone to wildfires and dieback in the decades ahead.
“The big concern looking into the future is that the land surface is doing us this big favor by soaking up about a third of our fossil fuel emissions every year,” said Brendan Rogers, an associate scientist at Woodwell Climate Research Center, formerly known as Woods Hole Research Center. “[But] is it going to continue doing that?”
If large forests can’t keep up, the carbon that doesn’t get absorbed by forests, oceans, or other carbon sinks could end up trapped in the atmosphere, contributing to the greenhouse gas effect, and worsening climate change.
Another concern, Rogers noted, is that the study undermines nearly all current climate models that assume forests are still actively absorbing tons of carbon.
“All these large models that inform us on, ‘Okay, how is climate change going to unfold and what does that mean for society?’ For the most part, the boreal forests in those models are doing great. They’re doing well and they’re going to continue to do well for the rest of the century,” Rogers said. “And so those models are not correct.”
“That’s a problem because it means that, ultimately, climate change will be unfolding faster than the models might say it will.”
The study, published in the Proceedings of the National Academy of Sciences and involving experts from around the globe, did, however, find that in Siberia, forests are adjusting, absorbing four times as much carbon as forests in Alaska and Canada. But Rogers said he worries things could get worse as temperatures rise and forests are impacted by drought, wildfire, and more.
“In Alaska and Canada and eventually in Siberia… these systems might eventually start being a source,” he said, “so that every year instead of soaking up carbon that we’re emitting, they’re actually adding to the problem.”
Now, Rogers said, he hopes policymakers and corporations will consider these impacts to re-evaluate the economy’s reliance on fossil fuels.
“It underscores the urgency,” he said. “We need to cut our fossil fuel emissions now. Not 20 years down the road; not 10 years down the road. Now.”
Without action, Rogers warned, the earth’s system will continue to change and may not keep doing us so many favors.