In the second of her Amazon on the Brink blogs, LAB author and editor Sue Branford looks at the climate science and relays the warning from veteran climatologist James Hanson about the dangers of a ‘super El Niño’, and the consequences for the rainforest. Fires, often set deliberately, are now a greater danger than deforestation.

Some climate scientists are worried that 2026 could be the hottest year ever and that 2027 will be even worse, with serious consequences for the planet, including the Amazon forest. Among those raising the alarm is 85-year-old James Hansen, who famously told the US Congress back in 1988 that humans were responsible for the planet getting hotter.

At the time, this was a controversial claim, as many climate scientists believed that global warming was a natural phenomenon, unrelated to human activity.  Though there are still a few discordant voices, most climate scientists today believe that Hansen’s statement was correct and a pivotal moment in climate science.

Hansen’s latest warning may appear bold, because the first three months of this year were cooler than the first three months of 2024 and 2025. As many of us in Europe remember all too well, January 2026 started with a harsh Arctic blast, bringing biting temperatures and widespread snow, contrasting with the record warmth in January 2025.

However, Hansen and other climate scientists believe that this was a one off, with the very real increase in the world’s temperature, created by global warming, being temporarily suppressed by La Niña, a climate pattern characterized by the cooling of ocean surface temperatures in the Pacific.

Hansen, always willing to speak his mind, is forecasting that by the second half of this year La Niña will probably be forced into retreat by El Niño, the planet-warming counterpart of La Niña, when warm water expands across the equatorial Pacific Ocean, heating the entire planet. Some models, he says, are predicting a ‘super El Niño’, perhaps the strongest ever, with a new global temperature record likely to be set this year and again in 2027, when the full force of the El Niño is felt.

If this is true, the Amazon basin will be affected by increased droughts and wildfires. The latter, which are extremely difficult both to prevent and to extinguish, are a significant threat to the Amazon forest. Already weakened, as it has become hotter because of global warming, the forest has also been ‘thinned out’, by the selective logging of hard woods. Together, these two factors have made the rainforest more susceptible to drying out and thus to fires.

Perhaps surprisingly, fires are now doing more damage than deforestation. Fires led to the estimated loss of 2.8 million hectares of primary forest in 2024, compared with 1.7 million hectares felled by deforestation. At the time, the region was experiencing a drought, which made it susceptible to wildfires but, even so, the phenomenon is concerning, as droughts are becoming more frequent.

President Lula has delivered on his electoral promise to take tough action to stop illegal deforestation in the Amazon forest. Brazil lost 28,000 sq. km. of primary forest in 2024, equalling a previous record. But the rate was nearly halved the rate in 2025 and Lula has, perhaps over-optimistically, promised to halt deforestation altogether by 2030.

Wildfires, however, are harder to control than illegal deforestation which can be spotted by satellite. Many fires are believed to be deliberately started by land grabbers for whom, outrageously, cleared land has a far higher market price than standing forest.

Prospects are not good. The ecology of the Amazon forest depends on it remaining a large single biome. The prevailing trade winds carry moisture across the Atlantic Ocean and it falls as rain over the Amazon region, as the winds move over land and lose heat. Cooler winds carry less moisture than warm ones.

Evaporation and transpiration (the process of water movement through a plant) return to the atmosphere three-quarters of the water that falls as rain. Further downwind, the moisture falls as rain again and returns again to the atmosphere. This cycle is repeated half a dozen times or more, fuelling the ‘flying rivers’ that carry moisture across the entire rainforest.

But this process depends on the forest being intact – If an area of forest is razed, more than half of the rainwater in that area runs off into streams and begins flowing back to the ocean. That reduces rainfall from transpiration, thus disrupting the flying rivers. Nico Wunderling, a researcher at the Potsdam Institute for Climate Impact Research, told Mongabay: ‘The reason why deforestation is so crucial is that it undermines this atmospheric moisture recycling feedback.’

So far, it is only the south of the Amazon basin that has been severely affected. The northern Amazon basin has suffered far less deforestation, he says, and has seen only a slight, statistically insignificant, decrease in precipitation.

Even so, scientists are concerned that the combined effects of heat, drought and deforestation could push the Amazon, or at least the south of the basin, to a tipping point that sees it transform into a different kind of forest.

There is uncertainty on how close this is to happening. A study last year found a 37 per cent chance of some Amazon dieback by 2100 if global warming, which currently stands at 1.4°C, reaches at least 2.2°C, as widely predicted. While that wouldn’t necessarily mean the rainforest will turn to savannah, it would mean a shrubbier forest holding fewer species and less carbon, says D.V. Spracklen, from the School of Earth and Environment at the University of Leads in the UK.

Spracklen and his colleagues found that climate models underestimate the impact of deforestation on rainfall by up to 50 per cent, which suggests the rainforest could reach this tipping point much sooner than expected. ‘The Amazon is more sensitive than we think, which is bad news,’ he says. ‘Maybe we’re closer to a deforestation threshold than we thought. But there’s a lot of uncertainty.’

To see the other blogs in this series, click here:

Main image: Aerial view of the rainforest. By Jorge.kike.medina – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=7318072