When Forests Make Rain

Tropical forests do not just receive rain; they help create it. Through evapotranspiration, trees pump water up from the soil and release it as vapor, which builds the very clouds that rain back down. The Amazon recycles a large share of its own rainfall this way.

Clear the trees and the cycle weakens, leaving the land drier. Push it far enough and scientists warn the forest could tip into dry savanna, taking its rainmaking power down with it.