About 40% of the Amazon rainforest's current area may enter a path of no return and become savannah at the end of this century, say researchers from Holland, Sweden, and Germany in a study published this Monday (5) in the journal Nature Communications.
The researchers used computer models and data analysis to estimate climate change, especially in relation to precipitation level.
According to the researchers, when the amount of rain falls below a certain limit, the forest can no longer return moisture, making the passage to savannah practically irreversible.
The objective was to help predict how current forests can be affected by changes in rainfall patterns caused by greenhouse gases.
The scientists simulated what would happen in two extreme scenarios: 1) if all forests in the tropics disappeared, where would they recover, according to climatic conditions ?, and 2) if there were forests throughout the tropical region, which areas would remain according to the climate?
Starting from a landscape without forests, the researchers noted that, as they increase in area, they start to affect the rains. The vapor from the leaves condenses and returns to the forest as precipitation, accelerating forestry, and creating a circle of more rain and more vegetation cover.
The feedback effect also appeared in the study that started with the tropics entirely taken over by forests. Today, rain is not enough to sustain a tropical forest, and with less vegetation cover, precipitation also falls, allowing for the appearance of fires, which further reduce the forest.
Translated by Kiratiana Freelon