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Tropical forests are very sensitive to changes in the level of rainfall and humidity and when there are fires or prolonged droughts some of the most affected areas can lose trees and characteristic vegetation, eventually becoming areas similar to savannas or pastures. It has long been known that the same could happen in the Amazon, mainly due to deforestation, the indiscriminate exploitation of the land and the fires that have devastated the South American jungle. However, the scientists considered that it would be decades before the changes in the Amazon rainforest were really noticeable.
A recent study, published Monday, shows that the transformation of the Amazon into a savanna may take place earlier than expected. About 40 percent of this tropical forest is currently at a critical point and may no longer have the characteristics of a tropical forest, according to a study published in the journal. Communications from nature.
Any conversion from a tropical forest to a savanna can take a few years to occur, but once this process has begun, it is difficult to reverse the situation.
“Tropical forests change the conditions on which they depend through feedback on different time scales. Those feedback shaping the hysteresis (historical dependence) of tropical forests, thereby controlling their resistance to deforestation and response to climate change “explain the study authors.
“The Amazon rainforest may partially recover from deforestation, but it may lose that resilience at the end of this century.”
Tropical forests are home to a much greater variety of plant and animal species than any savanna and, in fact, play a very important role in absorbing carbon dioxide from the atmosphere.
“Tropical forests are important regulators of global climate and the effects of their loss can spread throughout the Earth system. In addition, they control the regional climate, improving the recycling of atmospheric humidity and increasing the levels of seasonal precipitation. or annually “, also read in the article.
The truth is that there are regions of the Amazon where rainfall levels have been greatly reduced due to climate change. In about 40 percent of the forest, rainfall is almost similar to that of some savannas., according to the study, led by the Stockholm Resilience Center and based on computer modeling and data analysis.
Last year, Brazilian President Jair Bolsonaro was warned by experts that the continued destruction of the Amazon by fires and loggers threatened the rainforest to turn it into a savanna. But of little use, since This year’s fires in the Amazon are the worst in the last decade, with incidences increasing by 60 percent.
Forests have their own systems but they do not regenerate on their own
Arie Staal, lead author of the study, told the guardian that although tropical forests produce their own self-sustaining rainfall in the right climate, they are also subject to drying out if subjected to inappropriate conditions.
“As forests grow and spread across a region, they affect rainfall”He explained. “Forests create their own rain because the leaves emit water vapor and it falls as downwind rain. The rain allows fewer fires, thus increasing the forest.”.
But if large areas of rainforest are affected or devastated, rainfall levels in the region will decline.
“The drier conditions make it difficult for the forest to recover and increase the flammability of the ecosystem”, these Steel.
The problem is that after the rainforest has turned into a mixture of wood and grass, like an open savanna, it is unlikely to naturally return to its former state.
“It is more difficult to come back from the ‘trap’ caused by feedback, since the open and dry ecosystem is more flammable and fires, in turn, keep the ecosystem open “explained the researcher.
The research team conducted computer simulations to try to understand where forests might be expected to exist in Earth’s tropical regions, given certain climatic conditions, and analyzed the minimum and maximum areas of probable forest cover. But the research went further: it looked at what might happen if greenhouse gas emissions continue to rise and found that the ability of forests to grow again, after the trees were devastated, would be greatly reduced.
Ingo Fetzer, a co-author of the paper, said they concluded that “Tropical forests on all continents are very sensitive to global changes and can quickly lose their ability to adapt”.
“Once destroyed, it will take many decades for its recovery to return to its original state. And since tropical forests are home to most of the world’s species, all of that will be lost forever.”, he concluded.
