The climate crisis turned the drought that struck the Amazon rainforest in 2023 into a devastating event, a study has found.
The drought was the worst recorded in many places and hit the maximum “exceptional” level on the scientific scale. Without planet-warming emissions from the burning of oil, gas and coal, the drought would have been far less extreme, the analysis found.
It also showed the drought was made 30 times more likely to happen by global heating. The return of the natural El Niño climate phenomenon is associated with drier conditions but played only a small role, the scientists said.
The climate crisis is supercharging extreme weather across the planet, but the extreme Amazon drought is a stark and worrying example because the rainforest is already thought to be close to a tipping point into a drier state. This would result in a mass die-off of trees in the world’s most important store of carbon on land, releasing large amounts of CO2 and driving global temperatures even higher.
Millions of people in the Amazon have been affected by the drought, with some rivers at their lowest levels for more than a century. There have been drinking water shortages, failed crops and power cuts, as hydroelectric plants dried up. The drought also worsened wildfires and high water temperatures were linked to a mass mortality of river life, including the deaths of more than 150 endangered pink river dolphins in a single week.
“The Amazon could make or break our fight against climate change,” said Regina Rodrigues, a professor at the Federal University of Santa Catarina, Brazil, and part of the World Weather Attribution team that did the analysis.
“If we protect the forest, it will continue to act as the world’s largest land-based carbon sink,” she said. “But if we allow human-induced emissions and deforestation to push it through the tipping point, it will release large amounts of CO2. We need to protect the rainforest and move away from fossil fuels as quickly as possible.”
Simphiwe Stewart, a researcher at the Red Cross Red Crescent Climate Centre in the Netherlands and also part of the team, said: “Many communities living in the Amazon simply haven’t seen a drought like this before. People were forced to make huge journeys, dragging boats over dried up sections of river, to access food, medicine and other essential goods. It’s critical that government interventions are geared towards supporting communities to prepare for intensifying drought as the climate warms.”
The analysis used peer-reviewed methods to compare droughts in today’s climate, which is 1.2C hotter, with those that would have occurred in a cooler, pre-industrial climate. The researchers looked in particular at “agricultural drought”, which accounts for both low rainfall and the evaporation of water from soils and plants driven by high temperatures.
They found that global heating is decreasing rainfall and increasing heat in the Amazon, making the drought from June to November 2023 about 30 times more likely. El Niño was responsible for some of the reduced rainfall, but the high temperatures were almost entirely due to climate change, making it the primary driver of the drought.
The extreme drought of 2023 would be expected about once every 50 years in today’s climate, the analysis estimated. But if global heating reaches 2C, such a severe drought would be expected every 13 years.
The scientists said the large-scale destruction of the rainforest for beef and soy production in recent decades had worsened the drought because the clearing of the vegetation means the land retains less water.
Recent data shows that the Amazon rainforest is approaching a tipping point, after which the rainforest would be lost with profound implications for the global climate and biodiversity. More than 75% of the untouched forest has lost stability since the early 2000s, the study showed, meaning it takes longer to recover after droughts and wildfires.
Gareth Redmond-King, at the Energy and Climate Intelligence Unit in the UK, said: “The Amazon rainforest is critical to regulating our planet’s climate, but this area of South America is also critical to the UK in an even more immediate sense.”
“About half of our food imports come from climate impact hotspots, including Peru, Colombia and Brazil, which are our top suppliers of bananas, avocados, melons and other fruit, as well as soya beans for feeding British livestock,” he said. “So climate change’s devastating effects on South America’s farmers last year may well translate into gaps on our supermarket shelves and higher prices for our food.”