Amazon Rainforest approaches “shift points” that could transform it into a drier savannah
THE Amazon Could be closer to a calamite tilting point which would transform the lush tropical forest into a drier savannah in a century, warn the researchers.
This massive change could be triggered by a combination of climate change and deforestation.
THE Amazon Rainforest is the The largest tropical forest Worldwide, covering more than 2.3 million square miles (6 million square kilometers) and hosting 10% of the world’s plant and animal species. THE Global fund Considers that the Amazon contains 99 billion at 154 billion tonnes (90 to 140 billion tonnes of metrics) of carbon and receives more than 70 inches (180 centimeters) of rain each year. As such, it constitutes a key element of the global cycles of water and carbon, which regulate the climate.
During the last century, tropical forests and the Amazon has become increasingly vulnerable to stressors such as drought And forest firerecent by recent climate change and widespread deforestation. The World Resource Institute World Forest Review believes that the Brazilian Amazon Lost 11,000 square miles (28,000 square km) of forest – an area about the size of the Massachusetts – in 2024 only.
Some scientists believe that these changes push the Amazon to a “Tilting point” where the lush tropical forest could turn into drier meadows. But other researchers disagree.
In a new study published on August 1 in the journal Geophysical research lettersScientists have revisited the uncertain future of the Amazon. “We are reasonably convinced that such a change is possible,” said the co-author of the study Friend AndrewProfessor of Earth Systems Sciences at the University of Cambridge. “The question is what degree of climate change and / or deforestation will lead to the change of the system,” Friend at Live Science told an e-mail.
In relation: What are the biggest tropical forests in the world?
Using a computer model, the team tested how the Amazon forest would react to the combined effects of climate change and deforestation. They used what is known as a “unique column model”, which in this case has simulated only an average location in the Amazon basin to represent the entire area in which the Amazon river and its tributaries flow.
This type of model captures some of the complexities of a 3D global climate model, but it does not take into account how humidity and precipitation can change in different regions of the basin.
Based on the model results, the researchers identified three tilting points in the Amazon system: a 65% decrease in forest coverage, a 10% decrease in humidity from the Atlantic Ocean, or a 6% decrease in precipitation. Beyond these thresholds, small changes in the region’s climate or the forest cover could push the forest to the edge, transforming the ecosystem into a meadow.
The knot of this change is a feedback loop between earth, vegetation and humidity in the atmosphere. The trees take water from the ground through their roots and release water vapor in the atmosphere through their leaves, by evaporation and perspiration. This water vapor condenses in the atmosphere to form the rain. Rainwater infiltrates the ground, where trees can access it. And therefore the cycle continues.
Friend explained that with fewer trees, there is less evapotranspiration and precipitation, which dries the forest and ends up transforming it into a savannah. “This change can be caused by deforestation, but climate change can also cause it, which changes the total quantity of water entering the Atlantic Ocean basin,” he said.
The team acknowledged that a limitation of its model was its inability to resolve spatial differences across the basin, because it focused on a single place.
Chris Boultona climatologist from the University of Exeter who led a Previous study of tilting pointsagreed. Boulton told Live Science in an email that is extremely important to take into account where deforestation occurs. “Deforestation areas near the Atlantic can prevent evapotranspiration near the forest, and less water finds its way in the deeper parts,” he said.
So what can we do about it? The authors said that an urgent action was necessary. They indicated that even at the lower end of Planned climate change scenariosContinuous deforestation could decimate the Amazon forest over the next 100 years.
“Climate change and deforestation must be reduced over the next 10 to 20 years if we want to be convinced that the system will remain intact,” said Friend. “Our understanding is far from complete, and we can be wrong about how the system will react to these threats, but it would be unlikely to count on this possibility.”
