Scientists are urging the government, especially in Brazil, to implement policies that deforest the Amazon and begin recovering rainfall. Because people are cutting down forests and burning fires, which allows moisture to escape from the ecosystem. Adequate deforestation could trigger a process called “dieback” so that rainfall dries up, burns, and becomes savannah-like, releasing 140 billion tons of carbon into the atmosphere.
Experts fear the Amazon rainforest has reached a catastrophic tipping point. Leading Rainforest scientists Thomas Lovejoy and Carlos Nobre warned in an editorial published Thursday that the world’s largest rainforest has put the Amazon on the brink of an irreversible process called “dieback.”
That view would turn the Amazon into an African-Savannah-type landscape. Tropical plants – and the animal they support – will disappear, releasing 140 billion tons of stored carbon into the atmosphere, raising the already rising global temperature.
“Today we are standing right in a moment of destiny,” Lovejoy and Nobre wrote in an editorial published in the journal Science Advances. Both scientists have studied the Amazon for decades. “The tipping point is here, now it’s now.”
Fear of spreading in the summer about this tipping point, when the fire spread to the Brazilian Amazon. Researchers have recorded more than 195,000 fires in Brazil this year. The Blaze Festival in August marked an 83% increase over the same period in 2018. But overall, this year was not unique. People have been burning such fires year after year to clear land for agriculture and mining, which is not a natural part of the Amazon ecosystem. Brazil saw more than 205,000 fires in 2017, more than 182,000 in 2016, and more than 212,000 in 2015.
This year’s fires, however, drew worldwide attention after the smoke billowed 2,000 miles into São Paulo. “The supernatural wind woke up the Brazilian people and truly the world that the priceless Amazon has spread to the brink of functional destruction and so do we,” writes Lovejoy and Nobre. “Deforestation will lead to bizarre loss of biodiversity, carbon and consequently human well-being.”
People are throwing away rainwater. The Amazon water cycle plays an important role in distributing moisture throughout the Americas. When it rains in the Amazon, at least 75% of that water returns to the air and moves west, cycling through the forest five to six more times before turning south under the pressure of the Andes Mountains. That humidity spread to every country in South America except Chile, which has been isolated by the Andes.
Climate models show that the humidity of the Amazon also affects rainfall in the United States. If the Amazon were completely deforested, rainfall in Texas would be reduced by 25%, the Sierra Nevada snowpack would be cut in half, and the coastal northwest would be reduced by 20%.
The Amazon water cycle relies on water vapor and rainwater vapor from the leaves of its trees. But the logging, mining, cattle and soybean industries are disrupting that cycle. When people continuously cut or burn the Amazon for this purpose, 50% of the rainwater in that region leaves the Amazon water cycle, flowing across clear lands to rivers and oceans. This will transform the Amazon into a Savannah-like landscape.
‘In the meantime, there are ominous signs’ People have already cleared trees from 17% of the Amazon Basin, a number that Lovejoy and Nobre call “enough and terrible”. The World Wildlife Fund estimates that if the current deforestation rate continues, it could rise to 27% by 2030. The Brazilian Amazon has typically deforested 20%. Within 12 months of the fire in August, the Amazon rainforest had reached its highest rate in 11 years, according to official data.
Warmer climates also increase the likelihood of crossing this dieback tipping point, as climate change leads to a decrease in rainfall and an increase in temperature, resulting in a drying up of the landscape. Part of the reason fires is so strong this summer is: the humidity in the Amazon usually suppresses fires before they get too big, but as the dry season gets hotter and longer, it produces more burning plants. Lovejoy and Nobre said the unprecedented drought hit the forest in 2005, 2010, 2015, and 2016.
They have also noticed that more and more Amazon species that need rain moisture are dying, and species that prefer arid climates are prospering. “There are already ominous signs of this in nature,” the scientists wrote. “Literally, not only can Amazon prevent more deforestation, but it also needs to be rebuilt now.”
