DEFORESTATION in the Amazon rainforest is creating more rainfall in the areas stripped of trees.
Frederic Chagnon and Rafael Bras of the Massachusetts Institute of Technology compared 75 years of rain-gauge records with satellite data of cloud and forest cover over Brazil. They found that about twice as many low-level clouds formed over deforested areas as over forest, leading to more rainfall in such places.
The extra clouds form because of contrasts between forested and deforested areas in, for instance, the rate at which water evaporates from them and the roughness of their surfaces. “It is a similar effect to…
