SARS, Ebola and now SARS-CoV-2: all three of these highly infectious viruses have caused global panic since 2002—and all three of them jumped to humans from wild animals that live in dense tropical forests.

Three quarters of the emerging pathogens that infect humans leaped from animals, many of them creatures in the forest habitats that we are slashing and burning to create land for crops, including biofuel plants, and for mining and housing. The more we clear, the more we come into contact with wildlife that carries microbes well suited to kill us—and the more we concentrate those animals in smaller areas where they can swap infectious microbes, raising the chances of novel strains. Clearing land also reduces biodiversity, and the species that survive are more likely to host illnesses that can be transferred to humans. All these factors will lead to more spillover of animal pathogens into people.

Stopping deforestationwill not only reduce our exposure to new disasters but also tamp down the spread of a long list of other vicious diseases that have come from rain forest habitats—Zika, […]