The El Niño southern oscillation is a natural climate pattern — warm water pooling in the eastern Pacific every three to seven years, shifting rainfall and temperatures across the globe. It has always caused droughts, floods, and agricultural disruption. What is different now is context. Prof Mat Collins of the University of Exeter, one of the world's leading experts on El Niño dynamics, describes the relationship between El Niño and human-caused warming as two separate forces that layer on top of each other. An already drought-stressed region gets hit again. A warming ocean baseline makes every El Niño peak higher than it otherwise would be. The numbers from this cycle are extraordinary. Sea surface temperatures in the El Niño region have already matched the 2015 record of 3°C above average — and the event hasn't peaked. Collins says temperatures are on course to reach 4°C above average, far beyond anything in the observational record, and possibly the strongest El Niño in a thousand years. But measuring against historical events is itself becoming harder because the baseline keeps rising. The impacts cascade globally. Indonesia faces intensified wildfires. The Amazon faces drought. The Indian monsoon has already weakened. The UK may see a wetter winter and a colder spring. Collins is careful to separate El Niño effects from broader warming signals — the 2023 European heatwaves and North American wildfires, he notes, were more likely climate change plus persistent weather patterns than El Niño, which operates on a lag. The critical scientific question — whether climate change is making El Niños more frequent and intense — remains unresolved but increasingly plausible. Collins co-authored research suggesting the signal will emerge first in rainfall patterns and expects clarity within a decade. James Hansen's hypothesis that human warming is behind this El Niño's abnormal strength is, in Collins' words, 'a plausible hypothesis but hard to prove.' The models suggest bigger and more impactful El Niños over coming decades; the observational proof hasn't caught up. The resilience picture is mixed. Forecasting has improved dramatically since the 1982-83 El Niño blindsided the world — the system now provides six to nine months of warning, enough to shift crop planting in Latin America and prepare wildfire defences in Southeast Asia. But forecasting capacity is not the same as adaptive capacity. The countries most exposed — poorer nations in the tropics — have the least infrastructure to act on warnings. Geoengineering options exist in theory. One paper suggests cloud-seeding over the eastern Pacific could cool ocean surfaces enough to terminate a big El Niño. Collins is skeptical: the heat originates in the deep ocean, so a suppressed event may simply reappear the following year. The primary response, he says, remains reducing greenhouse gas emissions — the structural driver that makes each successive El Niño more dangerous. The twenty-year trajectory is stark. If emissions continue on current paths, each El Niño cycle stacks on a higher baseline of ocean heat, making what is already a record-breaking event look modest by the 2040s. The costs fall disproportionately on the Global South, amplifying existing inequalities in climate vulnerability. The science is clear enough to act on; the question is whether the political will matches the forecast window.
