The Amazon forest is approaching a point of no return under the effect of climate change and could turn into an arid savannah within half a century, warn researchers in a study published in Nature communications.
Another major ecosystem, the coral reef in the Caribbean, could disappear in 15 years if it too passes a point of no return, scientists in the same study said.
Such changes would have dramatic consequences for humans and other species that depend on these habitats, they warn. 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.
Freezing estimates
According to the work of UN climate experts, the IPCC, 90% of corals in shallow waters will be condemned if global warming reaches 1.5 ° C compared to the pre-industrial period. An increase 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 the Amazon rainforest, which covers more than five million km2 in seven countries, has been razed since 1970, largely to cultivate soybeans, wood, palm oil, biofuels or 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 Amazon ecosystem could thus tip over next year, according to him and his colleagues.
Forest fires out of control in the Amazon or in 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.
Ecosystems can change, sometimes quickly, under stress. Researchers studied such changes in 40 natural regions of different sizes.
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