A Severe Drought Pushes an Imperiled Amazon to the Brink

The planet’s biggest freshwater tank is in trouble.

The Amazon rainforest, where a fifth of the world’s freshwater flows, is reeling from a powerful drought that shows no sign of abating.

Likely made worse by global warming and deforestation, the drought has fueled large wildfires that have made the air hazardous for millions of people, including Indigenous communities, while also drying out major rivers at a record pace.

One major river reached its lowest level ever documented on Monday, while others are nearing records, suffocating endangered pink dolphins, shutting down a major hydropower plant and isolating tens of thousands living in remote communities who can only travel by boat.

“There’s just dirt now where the river used to be,” said Ruth Martins, 50, a leader of Boca do Mamirauá, a tiny riverside community in the Amazon. “We’ve never lived through a drought like this.”

The drier conditions are accelerating the destruction of the world’s largest and most biodiverse rainforest where parts have started to transform from humid ecosystems that store huge amounts of heat-trapping gases into drier ones that are releasing the gases into the atmosphere. The result is a double blow to the global struggle to fight climate change and biodiversity loss.

“This is a catastrophe of lasting consequences,” Luciana Vanni Gatti, a scientist at Brazil’s National Institute of Space Research who has been documenting changes in the Amazon. “The more forest loss we have, the less resilience it has.”

Recent studies have shown that climate change, deforestation and fires have made it harder for the Amazon to recover from severe droughts.

And, Ms. Gatti warned, the worst may be yet to come. The rainy season is expected to start in the next weeks and if the drought, which started in June, persists it would mark the first time such extreme conditions took hold in the Amazon’s driest period and continued into its wettest.

In Tefé, a rural municipality in the northwestern Amazon, residents are crossing muddy stretches of lake bed on motorcycles and paddling canoes down narrow streams that were once rivers. Some 158 riverside villages in the same region have been left stranded as waterways linking them to bigger towns have dried up, said Edivilson Braga, coordinator of the local civil defense service.

“They’re completely cut off,” he said, adding that so far authorities have delivered thousands of basic food baskets, many by helicopter, to thousands of families.

The Amazon has experienced droughts in the past, but it’s now facing “simultaneous disasters,” said Ayan Santos Fleischmann, a hydrologist at the Mamirauá Institute, a research organization based in Tefé. Scarce rainfall, scorching heat and scalding water temperatures are battering the region all at once.

“This is a crisis — a humanitarian, environmental and health crisis,” said Dr. Fleischmann. “And what scares us most is what lies ahead.”

In Boca do Mamirauá, about two hours by speedboat from Tefé, drying waterways have caused stocks of basic food items and medications to dwindle and prevented children from making the river journey to school since Sept. 20, said Ms. Martins, the community leader.

Across the Amazon, wells and streams have dried up, leaving communities without clean drinking water. “The water turned to mud here,” said Tuniel Gomes Figueiredo, who lives in Murutinga, an Indigenous village of about 3,000 people.

With no alternative, some residents are drinking, cooking and bathing with contaminated water. “This water is making children sick, it’s making elderly people sick,” Mr. Braga said. Health authorities also worry that stagnant pools of overheated water could breed mosquitoes carrying malaria and dengue.

The drought has stressed countless animal species in a region known for abundant wildlife. In Lake Tefé, water temperatures remain high and the carcasses of more pink river dolphins have surfaced over the last week, bringing the death toll to 153 since the first carcasses were recovered on Sept. 23, Dr. Fleischmann said.

A toxic algae bloom, likely linked to the drought and extreme heat, has also proliferated in the lake, creating a red stain in the water, although scientists are unsure if it could harm humans or animals. “We’re using nets to try to steer the dolphins out of this area,” Dr. Fleischmann said.

While low humidity and high heat alone can kill some plants and animals, much of the destruction is caused by the drier forest’s increased vulnerability to fires typically started by farmers and others who clear the land. Wildfires have consumed more than 18,000 square miles of the Amazon since the start of the year, an area twice the size of Vermont.

Smoke from wildfires turned the air so hazardous in Manaus, a city of two million in the heart of the Amazon, that it recently became one of the most polluted cities on the planet, according to the World Air Quality Index project. Checking air quality data each morning has become an anxious habit in the city, as children and older people have ended up in hospitals struggling to breathe, according to doctors in Manaus.

Camila Justa, a veterinarian in Manaus, said she has never seen such heavy smoke blanket the sky and suffered an asthma attack for the first time in 20 years, while her 4-year-old son has had pneumonia twice since September.

“It’s really hard to fill your lungs with air,” she said. “And, when you do, it burns.”

The drought has parched countries across the Amazon region. In Bolivia, dozens of municipalities have dwindling water supplies, crops have shriveled and lagoons have dried up, “with great consequences to biodiversity,” said Marlene Quintanilla, a research director at the Friends of Nature Foundation, a nonprofit group.

The lack of rain in the Amazon is largely the result of two climate patterns, experts said.

From the west, El Niño, which warms waters in the Pacific near the Equator, is gaining strength. From the southwest, high temperatures in North Atlantic waters have accelerated the air flow toward the Amazon, preventing rain clouds from forming above the forest.

While the link between human-caused global warming and the drought is still unclear, climate models suggest that “over the next decades, with the increase in temperatures caused by climate change, these events will become more frequent,” said Gilvan Sampaio, a scientist monitoring climate patterns at Brazil’s National Institute of Space Research.

The effects of a changing climate are intensified by high deforestation levels in the Amazon, as farmers clear land for soy and cattle farms whose products are exported to countries around the world. Cutting down trees, like global warming, makes rain scarcer and temperatures higher because the Amazon’s trees release moisture, cooling temperatures and forming rain clouds.

Drying rivers are also a blow to the region’s economy. Barges that move corn bound for China and other countries were forced to reduce their cargo by half along an important river this month because the water was too shallow, and the erosion of a riverbed caused one port to collapse.

The Amazon’s rivers also fuel power plants that produce over a 10th of Brazil’s electricity and the lack of rain led one power plant to shut down.

Similar drought conditions were documented in 2015, contributing to the Amazon’s worst fire season on record. But scientists expect this drought to be even more devastating because the Atlantic Ocean is warmer and El Niño hasn’t yet reached its peak.

“This is just the beginning,” Dr. Gatti, the scientist, said.

On a recent afternoon, heavy clouds darkened the skies over the riverside village of Boca do Mamirauá. People scrambled to grab buckets, ready to fill them with rainwater. But the ominous clouds passed quickly. “Not a single drop,” Ms. Martins, the community leader, said.

“We’re just praying for the rain to come.”