More rain, fewer droughts – rainfall effects from targeted forestation can reduce climate change

By prioritizing targeted increases in rainfall, forestation programs may not only mitigate global climate change itself but also reduce its concrete negative effects such as droughts. That is the conclusion of a new study led by the Copernicus Institute of Sustainable Development at Utrecht University.

As climate change is creating or intensifying droughts across the globe, targeted ecosystem restoration is an effective countermeasure through planting trees that generate rainfall regionally, argue researchers from Utrecht University, Potsdam Institute for Climate Impact Research and Stockholm Resilience Centre researchers in an Opinion article in Global Change Biology.

The researchers describe how forestation can promote rainfall by enhancing evapotranspiration which in turn increases the moisture in the atmosphere. “Models provide evidence that targeted rainfall enhancement through forestation would be beneficial in some cases,” says lead author Arie Staal, an assistant professor at the Copernicus Institute of Sustainable Development.

Potential application in drying regions

Focus areas for forestation with targeted rainfall enhancement could be the southern Amazon, Mexico, eastern China and Mediterranean Europe - as these regions are projected to become drier due to global climate change.

Regardless of their positive hydrological effects, massive increases in forest growth should not come at the expense of native well-functioning ecosystems such as natural grasslands nor should they endanger local water resources, the authors of the study stress. “Locally, trees may deplete water, so it is important to assess the hydrological effects of forestation on a case-by-case basis. But if done wisely, forestation could be used to reduce climate change-induced drying over downwind regions in need of water,” says Staal.