A new type of weather began to penetrate the Amazon. Scientists named it “hypertropical climate” and is characterized by conditions of extreme heatlarger than is already common in the jungle, and … A a deep drought. Its progress, for the moment timid, is barely beginning to be felt, but its consequences on the Amazonian forest are clear: it causes death of the tree and affects the Earth’s ability to handle increasing levels of atmospheric carbon dioxide.
These are the conclusions of a new study published Wednesday in ‘Nature’, which analyzes the impact of rising global temperatures on tropical forests, which already constitute one of the hottest and wettest ecosystems in existence. But by the end of the century, “we could create a climate that has been absent on Earth for millions of years: The “hypertropics”, say the authors. And it can appear outside of the Amazon, such as in the rainforests of West Africa and throughout Southeast Asia. By 2100, the tropics would become the hypertropics, where extremely hot drought days would no longer be limited to the peak of the dry season, but would occur more frequently throughout the year, even during the rainiest months.
For now, the conditions of this hypertropical climate only occur during a few days or weeks during periods of extreme drought in the Amazon. But they have important repercussions: increase the mortality rate by 55% trees. This happens because when the soil dries out and the moisture content drops by a third, trees stop capturing carbon and starve; or even suffer from hydraulic collapses, similar to an embolism, with air bubbles in their sap.
“Normally, plants are pretty good at trying to compartmentalize and just say, ‘Okay, I’m willing to sacrifice this branch to keep this central part alive,'” says study leader Jeff Chambers, a geography professor at the University of California, Berkeley. “But if there are enough embolisms, the tree just dies.” As the authors observed, species of fast growing trees were more sensitive than those with slow growth.
As global warming progresses, hypertropical weather conditions will also become more common. They calculate that, if emissions are not stopped, by 2100 intense droughts could reach up to 150 days per year and could lead to wider processes of forest dieback, they warn.
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