This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: During the 2023–2024 El Niño, about 75% of the world's tropical forest areas experienced at least six months of unprecedented simultaneous drought and heat. According to a study published in Earth's Future, this scenario offers more than just a snapshot of an extreme event; it offers a preview of the "new normal" for the next two decades if greenhouse gas emissions are not reduced.
The Amazon is the region most vulnerable to this new climate pattern, raising the greatest concern. If global greenhouse gas emissions continue to rise, the likelihood of the biome experiencing droughts as severe as those of the past two years will increase ninefold by the end of the century, even in years not influenced by El Niño. Under thermal stress of this magnitude, tropical forests undergo functional collapse.
According to the researchers, instead of absorbing the gases that warm the planet (acting as sinks), these areas temporarily begin to emit carbon into the atmosphere. Faced with this vicious cycle, the study reinforces the urgency of rapidly and sustainably reducing global emissions. The need for mitigation is even more urgent in light of the impending 2026–2027 El Niño event.
Its effects are already being felt in South America, and forecasts indicate that it will reach the "very strong" category (the highest classification) by the start of summer. Fueled by the climate crisis, this El Niño is on track to be the most intense ever recorded. Overall, the study found that high average temperatures are expected to become at least six times more likely across all tropical regions, even under a scenario of lower global emissions.
Under this scenario, by around 2075, the world will emit an amount of carbon equivalent to what it removes from the atmosphere—a condition known as net-zero CO₂ emissions. "During the 2023–2024 El Niño, the area and duration of droughts and heat waves were the largest and most extensive in the past 25 years. When we apply the same models to the future, we see that temperatures are rising.
We're concerned because, unfortunately, it could be even worse now," says Johanna Van Passel, the corresponding author of the article. Van Passel is a scientist at Ghent University in Belgium and a visiting researcher at the Institute of Biology at the State University of Campinas (IB-UNICAMP) in Brazil. El Niño is a natural phenomenon characterized by the abnormal warming of tropical Pacific waters, particularly off the coast of South America and in the central region of the ocean.
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