Impact of Amazon's climate-driven drought may last until 2026

The drought has killed endangered river dolphins and triggered deadly riverbank collapses

A dead dolphin is seen at Tefe lake, which flows into the Solimoes river, that has been affected by the high temperatures and drought in Tefe, Amazonas state, Brazil, October 1, 2023. REUTERS

The Amazon rainforest's record-breaking drought hit home for Raimundo Leite de Souza one October morning, he said, when he woke to find the stream that runs behind his house had dropped nearly a foot overnight, stranding his skiff in a mudflat.

As weeks passed, Souza said, rotting fish washed up on the banks of the Jaraqui, a tributary of the Rio Negro. Rodents thrashed in the mud, searching for water. Carcasses of caimans and cobras turned up in the forest.

Finally, Souza, an innkeeper and community leader in Bela Vista do Jaraqui, said he rallied two dozen neighbours to drill a 60-meter well in the heart of the world's largest freshwater basin.

"Never in my 37 years have I seen anything like this happen to our stream," he said.

Driven by climate change, the drought gripping northern Brazil, Guyana, Suriname, French Guiana and parts of Venezuela and Colombia has sapped the Amazon River and four of its biggest tributaries to their lowest levels in at least half a century.

It has killed endangered river dolphins and triggered deadly riverbank collapses. With rivers forming the backbone of transportation across the Amazon region, the drought has disrupted access to food and medicine in dozens of cities. And, in one of the world's top food producers, it has wiped as much as 10 million metric tons off initial forecasts for next year's soybean crop.

In a threat to the global climate, the drought could also double the mortality rate of the rainforest's largest trees, releasing the huge amounts of climate-warming carbon they collectively store in their wood, according to scientists.

The Amazon, the world's largest rainforest, is regarded by scientists as a bulwark against climate change because its dense vegetation absorbs carbon and emits oxygen.

"Even if we don't knock down one more tree, the Amazon could reach its point of no return," Brazilian President Luiz Inacio Lula da Silva warned the United Nations COP28 climate summit on Friday.

The worst may be yet to come, with experts predicting an even more intense drought next year.

Reuters interviewed nine scientists who said the drought, which began in April, is likely to weaken the annual rainy season now underway and last until the next rainy season in late 2024.

Five of those scientists said the Amazon is unlikely to make a full recovery before early 2026, at best, because it may take two healthy rainy seasons to restore the forest's normal soil moisture.

"This is the overture," said Michael Coe, director of the tropics program at the U.S.-based Woodwell Climate Research Center and one of the scientists expecting the effects of the drought to linger into 2026. "Where we are now, we're just getting started."

The five researchers predicting a 2026 recovery said the effects of the drought could endure even longer if El Nino is prolonged.

The naturally occurring phenomenon roils global weather every two to seven years, warming waters off the Pacific coast of South America and pulling rains in that direction while depressing precipitation in the Amazon.

Four of the scientists said it was hard to predict precisely when the rainforest would recover from this drought, given the uncertainty in any long-term weather forecast.