I think the sentence "More trees equals less global warming" is pretty intuitive to most of us. But where can we see actual evidence and progress related to this statement? Answer: the southeast United States.
Like most of the world, the U.S. has warmed up since the industrial revolution and implementation of coal and fossil fuel burning practices. But for a long time scientists were puzzled by a "warming hole" covering parts of the southeast U.S. in which temperatures have flatlines or even cooled in the face of the undeniable broader warming trend. A new study has found that the expansive reforestation of the American southeast over the last century after the initial deforestation created by European settlements has helped stall the effect of global heating. Through these trees' transpiration, water is drawn into and through the roots up to the leaves where it is released into the air as vapor and slightly cools the surrounding area. Forests today cool the eastern United States by 1 to 2 degrees Celsius (1.8 to 3.6 degrees Fahrenheit) each year. On the hottest days of summer, researchers found the trees have the strongest cooling effect by lowering the temperatures by up to 5 degrees Celsius (9 degrees Fahrenheit).
It is cautioned though, that bringing back trees isn't the sole cause of the stalled warming according to the researchers. Factors such as airborne pollutants (which block incoming sunlight) and agricultural irrigation could be potential causes as well. But these findings concerning the tree coverage should bolster efforts to provide thoughtful reforestation, particularly around urban environments, according to Barnes, the leading researcher. "Nature-based climate solutions like tree planting won’t get us out of this climate change problem,” she said. “If anyone thinks we can just plant a few trees and be OK, they are wrong – we need a massive reduction in fossil fuel emissions to hit our targets. Reforestation is something that needs to happen in addition to, not instead of, cutting emissions.”
Sources:
https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2023EF003663
https://www.theguardian.com/environment/2024/feb/17/us-east-trees-warming-hole-study-climate-crisis#:~:text=In%20all%2C%20the%20replenished%20forests,9F)%2C%20the%20researchers%20found.
Photo by Lauri Poldre: https://www.pexels.com/photo/young-coniferous-forest-17511054/
