By: Zofie C.
Photo from: Getty Pages
Deforestation occurs when trees are removed from land, which is then converted for other uses such as farming or construction. It has long been regarded by environmentalists and ecologists as a problem, as it is known to cause an increase in carbon emissions and is estimated to be the cause of approximately 10 percent of global warming (Union of Concerned Scientists).
However, there is another, lesser circulated, side to the story. As it turns out, deforestation does not always contribute to global warming and, in fact, can help to cool the planet. A recent 2021 study headed by Christopher A. Williams has corroborated research from 2007 and 2011 that found that deforestation in certain areas can actually have a net cooling effect on the planet, as opposed to a net warming effect.
Photo from: Marizilda Cruppe / WWF-UK
Williams found that deforestation in “West Coast states and East of the Mississippi River typically yields net warming,” while the albedo (a thermodynamics term that refers to how well a surface reflects the light and heat emitted by the sun, ranges from 0 to 1 where 0 is a perfect absorber of solar energy and 1 is a perfect reflector (National Snow and Ice Data Center)) of snow and land that covers the western United states yields “persistent net cooling from forest loss. Thus, protecting Intermountain West and Rocky Mountain forests or expanding forest cover in these regions to combat climate change is likely to be counterproductive,” (Williams). These findings suggest that a smaller number of trees in areas with high quantities of snow or flat land (closer to an albedo of 1) aid in cooling the planet due to their reflective properties.
Asbestos levels of various surfaces. Photo from: Wikipedia
According to another study published in Proceedings of the National Academy of Science, “forests' other climatic effects can cancel out their carbon cleaning advantage in some parts of the world,” (Swaminathan). The carbon sinks that are produced by forests are apparently only fully effective in tropical areas, causing either no cooling effect or even causing further warming to the earth. In tropical regions, trees use evapotranspiration (the process of the leaves of the tree canopy reflecting solar energy and thus producing a higher albedo for the area), however, in snowier areas, this can actually produce a warming effect because the combination of a lack of cloud cover with the large amounts of solar energy absorbed by trees negates any potential benefits created by the ability of a tree to store CO2 (Swaminathan). Essentially, non-tropical areas, because of the large quantities of solar energy being absorbed by trees, do not offset global warming. A similar result was found in midland and other regions.
In his study, Williams suggested a policy for managing forests and reforestation similar to that which is currently in place for the carbon emissions of businesses all over the world: a carbon offsets program. This is an effective way to ensure that the planet remains populated by trees and other vegetation and wildlife, while managing the quantity of CO2 being released into the atmosphere and mitigating the effects of climate change and global warming that occur due to changes in the albedo of the earth’s surface. While these findings don’t mean that people should start cutting down trees (they are great for biodiversity), it is certainly time for conservation groups and environmentalists to look at more widely-ranging solutions to global warming and climate change, like carbon offsets and reforming the energy system to emit less pollutants, as planting trees clearly is neither expansive enough nor effective at reducing global warming and carbon emissions.
Discussion Questions:
What are some possible solutions to reducing carbon emissions, climate change, and global warming that target our current energy infrastructure?
How do you think that scientists and policy-makers could use these findings to come up with a more comprehensive plan for attacking the issue of global warming?
Further Reading: