Research finds El Niño events intensifying alongside global warming

Cole, a researcher at the University of Michigan, explained the significance of the finding. 'That's important because strong El Niños have much greater impacts on climate hazards and extremes around the world,' she said. 'When we set out to answer the question of why this might be happening, we compared our data with a global temperature record and found that the increase in El Niño strength closely resembles the rise in global temperature that is due to human causes such as burning fossil fuels.'

How the study compared past and present

The study uses climate proxies — including coral records and other natural archives — to extend the record of El Niño variability back well beyond the period covered by direct measurements. By comparing those reconstructions with temperature estimates, the researchers argue that the trend toward stronger events is not simply a feature of natural variability.

Co-author Kim Cobb, also based at the University of Michigan, has published separate work on coral-based climate reconstructions in the Pacific. Together the team has emphasized that the strongest El Niño events of the modern era appear to stand out against the longer historical baseline the proxies reveal.

The implications stretch beyond the Pacific basin. Strong El Niño events can shift rainfall patterns across the Americas, Africa and Asia, alter hurricane tracks in the Atlantic, and amplify heat waves in normally temperate regions. Researchers studying the trend say the combination of stronger El Niños with an already warming climate could compound extreme weather risks.

Why stronger El Niños matter globally

The findings add to a growing body of research pointing to human influence on large-scale climate systems. While individual El Niño events still vary naturally in timing, the research suggests the upper end of their intensity range is climbing in tandem with global mean temperature.

Scientists say the work underscores the value of extending climate records beyond the instrumental era. Paleoclimate data make it possible to test whether modern changes fall outside the range of what the climate system has produced in past centuries, providing a longer baseline against which to assess current trends.

What the research could change

The research is expected to inform discussions about how societies prepare for climate hazards. With stronger El Niño events projected to coincide with continued warming, adaptation planning for floods, droughts and heat waves is likely to require updated assumptions about how extreme these events can become.

The University of Michigan team has not yet published a final peer-reviewed version of the analysis at the time of the report, but the conclusions are consistent with multiple other studies pointing to a strengthening of El Niño under warming scenarios.