Super El Niño: The northern Amazon faces unprecedented climate stress

As El Niño looms, study finds rapid growth in climate extremes is hitting an unexpected region of the Amazon hardest

A study led by Lancaster University and WWF-UK reveals that the central north Amazon, a region previously considered relatively safe from severe climate impacts because of its extensive intact forest cover, is experiencing the basin’s fastest acceleration in climate extremes.

Published in Communications Earth & Environment, the high-resolution assessment shows that extreme temperatures and water stress are escalating far faster than regional average temperature trends suggest.

Unexpected vulnerability in the Central North Amazon

While the Southern Amazon continues to lead in average temperature increases, largely driven by historical deforestation and agricultural land conversion, the central north Amazon is experiencing the steepest growth in extreme temperature and drought events.

Because the central north lies far from the main “arc of deforestation,” researchers attribute these rapid localised extremes directly to global climate emissions rather than local land-use changes.

Key statistical findings from the 43-year high-resolution dataset (1981–2023) include:

• Spatial extent of extremes:

  • Over 10% of the Amazon basin, an area exceeding 700,000 square kilometres (larger than Afghanistan), is experiencing dry-season extreme temperature increases of at least 0.75 °C per decade, totalling a rise of more than 3.22 °C since 1981.

• Discrepancy with average climate models:

  • Overall average temperatures across the Amazon have risen by 0.21 °C per decade, matching the global warming average. However, focusing solely on average temperatures obscures the sharp, dangerous spikes during peak dry seasons.

• Methodological precision:

  • Using an 11 km grid resolution, the international team modelled temperature and a novel vapour pressure deficit measure to evaluate both “central tendencies” (mean shifts) and “extreme tendencies” (the severity of exceptional dry and hot periods) across distinct northern and southern dry seasons.

Ecological and socio-economic impacts

The acceleration of climate extremes is already driving severe ecological shifts and human health crises across the basin:

• Wildlife and ecosystem degradation:

  • Extreme heat and dry conditions have triggered large-scale forest fires, tree mortality, shrinking bird populations, and the first recorded mass mortality events among Amazonian mammals, such as sloths dying on the forest floor and understory branches.

• Threats to local bio-economies:

  • In drying sub-basins, falling river levels hinder navigation and isolate indigenous and riverine communities. The loss of key forest products like açaí undermines local food security and threatens state-level forest restoration initiatives.

• Air quality hazards:

  • Reduced river flow and intense drought have fueled megafires, producing severe smoke pollution in major urban centers such as Manaus.

Looming Super El Niño and call for global action

With a major El Niño forecast for 2026, coming just two years after the severe 2024 Amazon drought, scientists warn that compounding extreme events risk pushing the Amazon rainforest past critical ecological tipping points into permanent biome transformation.

Lead author Professor Jos Barlow and co-authors emphasise that local adaptation measures, including enhanced fire-fighting infrastructure, river navigation support, and zero-deforestation mandates (such as the Tropical Forest Forever Facility), must be paired with aggressive global emissions reductions to achieve climate justice for the region.