A Deeper Dive into Deforestation: Part 1

Written by: Caroline Kim

November 7, 2021

After last week’s overview on deforestation and some solutions, I thought I’d go more in depth on the topic. So, here is part 1 of a briefer analysis of the article written by Deborah Lawrence and Karen Vandecar’s “Effects of tropical deforestation on climate and agriculture”. This article provides some very insightful views on deforestation and all the different ways it impacts the world. The first topic this article reviews is general circulation models, which essentially allow researchers to model the effects of the climate (which is closely tied to deforestation) on the environment. Through this modelling method, researchers can predict the patterns of deforestation and its behaviors. The authors introduce the facts by making note of the fact that regional deforestation can vary from soil type, topography, vegetation, the land spread, and climate type. Because of all these factors, they explain that deforestation can never be conformed to one single outcome and behavior in all places.

Through models, the authors were able to conclude that through deforestation, rainfall was reduced in certain regions such as the Gulf of Mexico, but increased in other areas such as the Arabian peninsula. After reviewing many studies with the general circulation models (GCM), information was found that tropical forest clearing exceeding 30-50% can cause reduced rainfalls which eventually lead to massive declines in the ecosystem and its function. This, too, varies according to the balance in land and oceans. The article also suggests that even small-scale deforestation in coastal areas can cause disruptions in the movement of moisture between oceans and continental interiors. Forests also tend to be important factors for the atmosphere as it controls evapotranspiration, condensation, temperature, and moisture. Next, comparisons are made between condensed and dispersed deforestation methods: smaller cells of deforestation that were separated by patches showed a smaller reduction in rainfall, but larger grids of deforestation patches showed even smaller reductions in rainfall. These findings signify the importance of how large patches of forest promote/sustain rainfall down wind. In terms of small-scale deforestation, it was found that small clearings resulted in increased rainfall over the deforested region. Simulations of rainfall were also done on forests, varying pastures, and it was once again shown that rainfall centers near deforested areas of land. They found that the magnitude of the increase in rainfall decreased as the size in patches of land increased.

These are just some of the findings so far in this informative article, and the other half will come next week, but if you are interested, I recommend you give the article itself a read as it goes more in depth and shares some detailed data/charts. I hope you will stick around for more quick and informative reads!

Sources:

Lawrence, Deborah, and Karen Vandecar. “Effects of Tropical Deforestation on Climate and Agriculture.” Nature Climate Change, vol. 5, no. 1, 2014, pp. 27–36., https://doi.org/10.1038/nclimate2430.