Deforestation is changing global rainfall patterns, says study

Tropical deforestation is going to have a significant impact on global warming and rainfall patterns which could cause agricultural distress, according to a new study by researchers at the University of Virginia.

The report, titled “Effects of Tropical Deforestation on Climate and Agriculture”,  published in the journal Nature Climate Change, on Dec. 21., is the most comprehensive analysis of tropical deforestation to date.

What role does deforestation play in changing rainfall patterns?

The study found that deforestation is already altering the rainfall patterns in the Amazon. The eradication of rain forests speeds up the rate at which carbon dioxide is emitted into the atmosphere. This accelerates global warming and changes rainfall patterns.

This could ramp up temperatures by 0.7 degrees Celsius, in addition to the influence of greenhouse gases. Crops would significantly suffer as a result of this increase.

Deborah Lawrence, professor at the University of Virginia and the lead author of the study, said:

“Tropical deforestation delivers a double whammy to the climate and to farmers. Most people know that climate change is a dangerous global problem, and that it’s caused by pumping carbon into the atmosphere. But it turns out that removing forests alters moisture and air flow, leading to changes—from fluctuating rainfall patterns to rises in temperatures—that are just as hazardous, and happen right away.”

Deforestation is predicted to cause a 15 percent drop in rainfall in tropical regions by 2050.

“What happens on the surface of the earth (in terms of changes in vegetation) is a big factor in climate change. We can ignore it at our own peril,” added Lawrence.

According to the study:

“General circulation models show that completely deforesting the tropics could result in global warming equivalent to that caused by burning of fossil fuels since 1850, with more warming and considerable drying in the tropics. More realistic scenarios of deforestation yield less warming and less drying, suggesting critical thresholds beyond which rainfall is substantially reduced.”


Deforestation in the Usambara Mountains in Tanzania.

Deforestation is already having an impact

Deforestation is already having an impact on regional climates. There was a significant decline in rainfall during Thailand’s dry season and in Sao Paulo, Brazil. Both these cases are believed to be a result of deforestation.

It is imperative that the problem is addressed

Deforestation of tropical forests is occurring at an alarming rate, posing a big threat to the planet. Of particular concern are forest-dependent communities, food stores, and the rate of agricultural production. The survival of low-lying nations are all likely to be impacted.


“Effects of tropical deforestation on climate and agriculture” – Deborah Lawrence & Karen Vandecar – Nature Climate Change 5, 27–36 (2015) doi:10.1038/nclimate2430