Contrary to most current thinking, the net effect of planting – or cutting down – trees could in theory be zero, or somewhere near that, depending on local factors.
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New research by Christopher A. Williams, an environmental scientist and professor in Clark University’s Graduate School of Geography, reveals that deforestation in the U.S. does not always cause planetary warming, as is commonly assumed; instead, in some places, it actually cools the planet, says Phys.org.
A peer-reviewed study by Williams and his team, “Climate Impacts of U.S. Forest Loss Span Net Warming to Net Cooling,” is published today (Feb. 12) in Science Advances.
The team’s discovery has important implications for policy and management efforts that are turning to forests to mitigate climate change.
It is well established that forests soak up carbon dioxide from the air and store it in wood and soils, slowing the accumulation of greenhouse gases in the atmosphere; however, that is not their only effect on climate.
Forests also tend to be darker than other surfaces, said Professor Williams, causing them to absorb more sunlight and retain heat, a process known as “the albedo effect.”
“We found that in some parts of the country like the Intermountain West, more forest actually leads to a hotter planet when we consider the full climate impacts from both carbon and albedo effects,” said Professor Williams.
It is important to consider the albedo effect of forests alongside their well-known carbon storage when aiming to cool the planet, he adds.
The research was funded by two grants from NASA’s Carbon Monitoring System. Williams and his research team—comprising data scientist Huan Gu, Ph.D. from The Climate Corporation and Tong Jiao, Ph.D.—found that for approximately one quarter of the country, forest loss causes a persistent net cooling because the albedo effect outweighs the carbon effect.
They also discovered that loss of forests east of the Mississippi River and in Pacific Coast states caused planetary warming, while forest loss in the Intermountain and Rocky Mountain West tended to lead to a net cooling.
According to Professor Williams, scientists have known for some time that expanding forest cover cannot be assumed to cool the planet or to mitigate global warming. However, this has not always been appreciated broadly.
Full article here.
via Tallbloke’s Talkshop
February 13, 2021 at 03:33AM