Amazon climate extremes are surging fastest in unexpected places

For years, the story of Amazon climate change centered on the south, the region hit hardest by deforestation and land clearing. A new study flips that assumption on its head.

The central-northern Amazon, long considered relatively insulated due to its intact forest cover, natural savannas, and vast indigenous territories, has quietly become the epicenter of the region’s most rapid climate extremes.

The findings come from a team led by researchers at Lancaster University, working with World Wildlife Fund UK and an international group of more than 50 scientists.

Extremes are outpacing the averages

The scale of change is striking. Across 10 percent of the Amazon basin, an area larger than Afghanistan, extreme dry season temperatures have risen by at least 0.75°C per decade, adding up to more than 3.22°C since 1981.

That number matters because it tells a different story than the one usually reported. 

Average Amazon temperatures are rising at 0.21°C a decade, roughly in line with global warming trends. But that average masks what’s actually happening at the extremes, and the extremes are getting dramatically worse.

A new way of measuring heat

To capture that gap, the research team first divided the Amazon into 11km grid cells.

They used high-resolution temperature and rainfall data, drawn from a combination of satellites and local weather stations, to identify the dry season for each individual area rather than treating the whole basin as one climate zone.

They also developed a new measure of water deficit that factors in how temperature affects water loss, then modeled temperature and water stress across the entire Amazon from 1981 to 2023. 

Crucially, the team looked at the data two different ways. They averaged change across all years, known as central tendency, and focused specifically on the most extreme years, known as extreme tendency.

“We are most interested in things when they are at their hottest and driest as that is when the most harm can be caused by high temperatures,” said lead author Jos Barlow from Lancaster University. 

“While this has been assessed in the Southern Amazon, which shares a largely similar dry season, it has never been assessed across the whole of the Amazon – which includes regions north of the equator which have a different dry season period.”

Two different maps of risk

That split matters because it reveals two very different pictures depending on which measure you use. 

The Southern Amazon, already known for extensive deforestation and land-use change, remains the fastest-warming region by average temperature. 

But when it comes to extremes, the central-northern Amazon pulls ahead.

“The rates of change in climate extremes are much higher than the rates of change of average climate in the Amazon, and the most affected regions are also different for extremes and average climate,” said co-author Nathália Carvalho, a postdoctoral research associate at Lancaster Environment Centre. 

“This is important because we show that Amazonia’s climate is not changing uniformly. This information will be crucial when planning and implementing climate change adaptation strategies.”

Not just a local problem

What makes the central-northern findings particularly alarming is where they’re happening.

This region sits well outside the so-called arc of deforestation, the belt of forest clearing typically blamed for local climate disruption in the Amazon.

“Extreme climate is a primary concern, contributing to forest fires, exceptional river levels, air pollution, and high temperatures that can harm people as well as animals and the forest trees. The rates of change that we are seeing in the most affected regions are very alarming,” Barlow said. 

“Given the area that is experiencing the fastest growth in extreme temperature is far from the arc of deforestation, these rapid rises cannot be explained by local changes such as deforestation and land-use changes.” 

“It’s showing how the Amazon is being affected by global climate change. It’s the world’s emissions that are responsible.”

A region already showing the strain

Recent studies have documented mass deaths of mammals in the Amazon, with sloths and other animals found dead on the forest floor or hanging from understorey trees.

Bird populations have shrunk, and scientists have recorded changes to bird lifespans, appearance, and behavior. 

Extensive wildfires, extreme heat, and drought have combined to fuel megafires, triggering air pollution as far as the city of Manaus, while drying rivers have hit the health of people who depend on them for daily life.

The human cost runs even deeper for communities whose livelihoods are tied directly to the forest. 

“Extreme climate events are impacting local livelihoods in many ways, affecting key products like açaí. This removes the safety net that forests provide, threatening food security and weakening their role in a growing socio-bioeconomy,” said co-author Joice Ferreira from the Brazilian Agricultural Research Corporation (Embrapa). 

“Most concerning, it could derail public policies currently being designed and implemented by Brazilian and state governments to drive positive transformation in the region, such as forest restoration plans. This scenario demands global action to halt climate change in the name of climate justice.”

A super El Niño on the horizon

The timing adds urgency. The possibility of a powerful El Niño in 2026 adds another layer of concern. It would come just two years after the region’s last major drought in 2024.

Scientists worry that if these rapid increases in extreme events continue, the Amazon could be pushed past critical ecological thresholds.

“Adaptation measures are urgently required to address the impacts of these rapidly changing climate extremes, including preventing factors that amplify climate risks such as deforestation,” Barlow said. 

“We also need to bring in measures to support the fighting of forest fires as well as supporting local people when the rivers they rely on for navigation dry up, especially in a year like 2026 with the arrival of a super El Niño.”

A global wake-up call 

For WWF-UK’s chief scientific adviser, Mike Barrett, the findings underline a dual challenge: tackling the global drivers of warming while also protecting the forest itself. 

“The rapidly increasing climate extremes revealed in this study highlight the urgent need for global action on climate change,” he said. 

“However, the new regions of risk also demonstrate the need to support other measures, including an end to deforestation and support for measures such as the Tropical Forest Forever Facility if we are to avoid critical tipping points and environmental collapse.”

Protecting the Amazon can no longer mean simply defending the areas already known to be under threat. 

As this research shows, the danger has spread somewhere few were watching, and the possibility of another major climate test is already raising concern.

The study is published in the journal Communications Earth & Environment.

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