Can reforestation cool the planet? New study reveals potential
Completely reforesting Earth might help cool the planet more than expected but still not enough to offset the warming that has occurred since industrial times, a recent analysis finds.
The scientists modeled what might happen if humans reached the planet’s reforestation potential, adding about 4.6 million square miles of trees and bringing Earth’s forests back to preindustrial levels.
The good news is that trees’ natural emissions could help with cooling, the researchers write in the journal Communications Earth & Environment.
The researchers predicted the outcomes of full reforestation both taking and not taking the effects of biogenic volatile organic compounds (BVOCs) into consideration. These natural, tree-emitted compounds interact with atmospheric molecules, encouraging cloud production, reflecting sunlight and cooling Earth’s surface.
In a news release, the researchers acknowledge that achieving full reforestation is not feasible. Nevertheless, they write, tree restoration may have “higher climate change mitigation potential” than previously thought thanks to trees’ atmospheric effects.
The scenario that took BVOCs into consideration showed more cooling than without tree emissions. But though both scenarios lowered Earth’s temperature, neither cooled the planet to preindustrial levels.
Overall, the researchers found, average global temperatures could fall by 0.34 degrees Celsius if the forests were restored. But that would not be enough to make up for the amount of warming since industrialization.
“Reforestation is not a silver bullet,” Bob Allen, a professor of climatology at the University of California at Riverside and the paper’s lead author, said in a news release. “It’s a powerful strategy, but it has to be paired with serious emissions reductions.”
Reforestation would have different effects in different parts of the world, with more cooling in tropical regions and more warming in areas of the Northern Hemisphere with lots of trees. (Northern trees tend to warm the atmosphere around them because of their dark color, which absorbs heat.)