Tefnut's Environmental and Drought News
What Drought in the Amazon Means for the Planet
By Nicolás Rivero
November 10, 2023 at 6:30 a.m. EST
The Amazon — the lush, tropical basin that holds the world’s biggest river, rainforest and a fifth of its fresh water — is running dry.
The region is entering its fifth month of a drought that has been particularly punishing in the northern reaches of the rainforest, in the region around the city of Manaus. The Rio Negro, a northern Amazon tributary, fell to the lowest levels in its recorded history last month. Wildfires have advanced where waterways have retreated.
“In my lifetime looking at drought impacts and fires, I’ve never seen so many wildfires happening so close to Manaus, a region that was not considered that flammable — or flammable at all — in the past,” said Paulo Brando, an associate professor at the Yale School of the Environment.
The effects of the drought are rippling through the forest. Travel and commerce along the river system have slowed to a crawl. Brazil shut down its fourth-biggest hydroelectric plant. Riverside cities and towns are rationing drinking water. Key fish species have struggled to spawn, threatening local food supplies, and endangered pink dolphins have washed up dead on the riverbanks.
“I never thought I’d see the bottom of this river that I’ve crossed every day for 14 years, and here I am looking at the bottom now,” said Taciana Coutinho, whose boat commute to work grew twice as long as the Amazon dwindled.
As the rainy season returns, river levels are starting to recover. But scientists are predicting below-average rainfall that could leave the region vulnerable again next year.
This year’s disaster follows damaging droughts in 2005, 2010, 2015, 2016 and 2020. Each successive blow — combined with ongoing deforestation and rising temperatures — chips away at the Amazon’s ability to bounce back and puts it closer to a tipping point at which parts of the rainforest could permanently transform into a savanna.
"The forest might be recovering from one drought and then get hit by another while it’s still recovering,” said Chris Boulton, a research fellow at the University of Exeter’s Global Systems Institute and lead author of a 2022 study on Amazonian tipping points. “If that happens, it can take even longer to get back to normal, and eventually it reaches a point where it can’t get back to normality.”
A degraded Amazon would have big consequences for the world’s climate. The ancient forest stores 123 billion metric tons of carbon — more than three times as much as humans emitted last year — and its intact western region pulls millions of tons of carbon out of the atmosphere each year. But wildfires and deforestation have turned the eastern fringe of the forest into a net carbon emitter.
The rest of the forest could face the same fate.
"The global impact of that is very, very, very risky,” said Carlos Nobre, an earth system scientist at the University of São Paulo’s Institute of Advanced Studies. “When the forest is losing more carbon than it is absorbing from the atmosphere, that shows we’re on the edge of this tipping point.”
A rainforest on the brink
This year’s drought is linked to a strong El Niño, a climate pattern that often leads to drier conditions in the Amazon. Rising temperatures from human-caused climate change are probably intensifying the drought by speeding up evaporation of water from land surfaces. As summer and fall temperatures have sharply risen in Brazil in recent decades, average rainfall over the country has seen a steep decline
Drought conditions over the rainforest region have reached the most extreme level over the last three months.
Big droughts used to rarely hit the Amazon — about once every 20 years or so, according to Nobre. But, due to climate change, they’ve come more frequently. “Unfortunately, in the last 20 years, this is becoming two strong droughts per decade,” he said. “That’s very much linked to global warming.”
Deforestation can also make droughts worse by making conditions drier.
The Amazon is so vast that it makes its own rain. Wet air from the Atlantic moves over land and dumps rain near the coast, watering the edges of the forest. The dense mass of vegetation releases moisture back into the air through a process called evapotranspiration. As winds blow that moist air deeper inland, more rain develops. The process repeats across the entire forest.
“That process simply needs the forest to be there in order to happen,” Boulton said. “If deforestation happens on the edge of the forest where the rainfall is coming in, there’s a breakdown in the ability for the forest to recycle” the water into the interior.
The environmental tipping points that could reshape the Amazon basin’s landscape could also trigger social tipping points that would transform the lives of the people in the region, said Simone Athayde, an environmental anthropologist at Florida International University.
“Also human populations can go through these thresholds,” she said. “They might get trapped into this poverty condition, and because they are facing successive disasters, they might not be able to recover to the conditions that they lived previously in terms of income and quality of life.”
But Athayde and Boulton both stressed that these tipping points are avoidable. Deforestation, the main driver of the crisis, accelerated under the pro-development administration of Brazilian President Jair Bolsonaro but has slowed in the early days of President Luiz Inácio Lula da Silva’s regime.
“We can model the climate quite well with our projections nowadays,” Boulton said. “But we can’t necessarily model how humans interact very well.”
A changing way of life
Every day for the past 14 years, Coutinho has commuted from her home in the Brazilian border town of Tabatinga to her job at the Federal University of Amazonas in Benjamin Constant on a motorboat down the Solimões River, the Brazilian name for the northern branch of the Amazon.
Normally, the trip is a half-hour jaunt across water as deep as 40 feet and a mile wide, lively with traffic from boats carrying children to school and merchants ferrying their wares.
“The river is a way of life for all of us in the Amazon,” said Coutinho, a professor in the Institute of Nature and Culture. “Everything that comes into my city, that comes into my house, that comes into the houses of all my neighbors, depends on the river.”
But for the past five months, the river has been transformed by drought. Water levels have dropped to about a foot, and the Amazon and its tributaries have become choked with sandbars. River traffic has slowed. Coutinho’s commute now takes over an hour. She says boat captains watch for pink river dolphins to guide them into navigable channels of deeper water.
In October, at the height of the dry season, Tabatinga’s water gauge sat on a bone dry river bank. Normally, it would measure 10 feet of water depth at this time of year, but Oct. 16, it gave a reading of -2.5 feet — meaning that the water had retreated to a shallow stream at the center of the river bed, two-and-a-half feet below the zero mark on the water gauge.
It’s a strange sight.
“The world looks to the Amazon as the solution to its problems,” she said. “But we have our own problems to resolve.”
Source: Washington Post
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