The Amazon could be nearing a tragic tipping point that turns lush rainforests into a dry savanna within a century, researchers warn.
This massive shift can be caused by a combination of climate change and deforestation.
The Amazon rainforest is the world’s largest tropical rainforest, covering 2.3 million square miles (6 million square kilometers) and covering 10% of the world’s plants and animal species. The World Wide Fund estimates that Amazon contains between 99 billion and 154 billion tonnes of carbon (90 billion and 140 billion tonnes) of carbon, receiving an average of 70 inches (180 centimeters) of rain each year. As such, it forms an important component of the global water and carbon cycle that regulates climate.
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In the past century, rainforests like the Amazon have become increasingly vulnerable to stressors such as droughts and wildfires, driven by recent climate change and widespread deforestation. The World Resources Institute’s Global Forest Review estimates that Brazilian Amazon lost 11,000 square miles (28,000 square km) of forest in 2024 alone, an area roughly sized in Massachusetts.
Some scientists believe these changes are heading towards a “tip point” where the Amazon can transform into a lush, rainforest into arid grasslands. However, other researchers disagree.
In a new study published in the journal Geophysical Research Letters on August 1, scientists revisited Amazon’s uncertain future. “The research co-author and professor of Earth Systems Science at Cambridge University,” said Andrew Friend, a research co-author who is a professor of Earth Systems Science at the University of Cambridge. “The problem is that the level of climate change and deforestation can change the system,” a friend told Live Science in an email.
Related: What is the largest tropical rainforest in the world?
Using computer models, the team tested how Amazon Rainforest responds to the combined effects of climate change and deforestation. They used what they called the “single column model.” In this case, only one of the average locations within the Amazon Basin was simulated to represent the entire area where the Amazon River and its tributaries were discharged.
This type of model captures some of the complexity of 3D global climate models, but does not take into account how moisture and rainfall change across different regions of the basin.
Based on the results of the model, researchers identified three tipping points in the Amazon system. A 65% reduction in forest cover, a 10% reduction in moisture from the Atlantic, or a 6% reduction in rainfall. Beyond these thresholds, small changes in either the local climate or forest cover push the forest towards the edges and turn the ecosystem into grasslands.
At the heart of this shift is the feedback loop between atmospheric land, vegetation and moisture. Trees take water from the roots from the soil and release water vapor through the leaves into the atmosphere by evaporation and evaporation. The water vapor condenses into the atmosphere to form rain. Rainwater penetrates the soil where the tree can access it. And the cycle continues.
My friend explained that fewer trees will dry out the forest and eventually turn it into a savanna, as it will cause less evapotranspiration and less rainfall. “The change can be caused by deforestation, but climate change can also cause it, changing the total amount of water entering the basin from the Atlantic,” he said.
The team acknowledged that one limitation of the model is that it cannot resolve spatial differences across the basin, as it focuses on one location.
Chris Boulton, a climate scientist at the University of Exeter, agreed to have led a study of previous tipping points. Boulton told Live Science via email that it is extremely important to consider where deforestation occurs. “Deforestation areas near the Atlantic Ocean prevent evapotranspiration near the edge of the forest and provide less water to enter the deeper areas,” he said.
So, what can we do about it? The author stated that urgent action is necessary. They have shown that even at the bottom edge of the predicted climate change scenario, deforestation could destroy the Amazon rainforest within the next 100 years.
“If we want to be certain that the system will remain intact, we need to reduce both climate change and deforestation over the next 10-20 years,” my friend said. “Our understanding is far from complete and we may be wrong about how our systems respond to these threats, but it is not wise to rely on this possibility.”
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