The Amazon rainforest is approaching a point of no return as a result of climate change. It could turn into an arid savannah in half a century, warn researchers in a study published in Nature communications .
The coral reef in the Caribbean, another major ecosystem, could disappear in fifteen years if it also exceeds a point of no return, scientists in the same study say. Such changes would have dramatic consequences for humans and other species that depend on these habitats, they warn.
Warming, deforestation, acidification…
In both cases, the causes of these modifications are climate change caused by humanity and environmental damage, deforestation in the case of the Amazon, pollution and ocean acidification for corals. According to the work of climate experts from the UN, the IPCC, 90% of corals in shallow waters will be condemned if global warming reaches 1.5 ° C compared to the pre-industrial period. A rise of 2 ° C will sign their almost complete disappearance. The warming has already reached 1 ° C.
Regarding the Amazon, the tipping point is less clear, but scientists believe that the loss of 35% of surface would trigger its disappearance. About 20% of this virgin forest, which covers more than five million square kilometers in seven countries, has been cleared since 1970, largely to grow soybeans, timber, palm oil, biofuels or l 'cattle farming.
"On the brink"
"Humanity must prepare for change much faster than expected," warned lead author Simon Willcock of the University of Bangor. The Amazonian ecosystem could thus tip over next year, according to him and his colleagues.
Forest fires that have gotten out of control in the Amazon and Australia suggest that many ecosystems are "on the brink," he added. "If we do not act quickly, we may be on the verge of losing one of the largest and most diverse tropical forests, which has evolved over 58 million years and on which tens of millions of people depend", says Alexandre Antonelli, of the Royal Botanic Gardens, Kew, who did not participate in the study.
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