Study - Devastating, Unprecedented Amazon Basin Drought Caused By Anthropogenic Warming

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A ferry boat is seen stranded at the Marina do Davi, a docking area of the Negro River in the city of Manaus, Amazonas State, northern Brazil, on October 16, 2023. The Negro River is facing the worst dry season of the last decades in the Amazon rainforest. Credit: Michael Dantas/AFP via Getty Images

Climate change was the primary driver of a massive drought in the Amazon basin in 2023 and will likely cause future extreme droughts, with potentially dire consequences for global efforts to cut greenhouse gas emissions, according to a new report from World Weather Attribution. The group, which assembles teams of scientists to rapidly assess if climate change had an impact on recent weather events, released a report Wednesday saying that the “exceptional” Amazon drought was 30 times more likely to have occurred because of climate change. “We’ve never seen anything like this before,” said Regina Rodrigues, professor of physical oceanography and climate at the Federal University of Santa Catarina in Brazil and a lead author of the new report. “And it was widespread in the whole basin.”

The Amazon basin, which extends into parts of nine countries but lies mostly in Brazil, is the single biggest land-based sink of carbon on the planet—storing up to five times the world’s annual greenhouse gas emissions. Its survival as an intact ecosystem is critical to stabilizing Earth’s atmosphere.

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Previous reports have shown that parts of the Amazon, mainly in the southeast—a region known as the “arc of deforestation”—has become a source of carbon, rather than a sink, because so much of the rainforest there has been felled for grazing lands and soybean fields. Now, researchers are concerned that the latest drought could turn more untouched and vulnerable parts of the Amazon basin into carbon sources. Rodrigues explained that northwestern parts of the Amazon, which are less impacted by human activity, are especially fragile because they haven’t adapted to the damage caused by human interference in the southern part of the region.

“Genetically speaking, that is more diverse and resilient, but ecologically speaking, is more vulnerable to physical drought,” Rodrigues said. “This is very problematic for the tipping point … The forest might not be able to cope.” Even if there’s adequate rain in the future, it might not make a difference. “If it gets too dry, it can actually trigger a die-back and become a savannah,” Rodrigues said. “Some projections show that even if you have precipitation, you might not get the Amazon back.” Rodrigues said that this dieback could continue even if fossil fuel use is slashed and the world meets targets for cutting greenhouse gas emissions. “It might be too late,” she said.

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https://insideclimatenews.org/news/24012024/a-historic-and-devastating-drought-in-the-amazon-was-caused-by-climate-change-researchers-say/