Jeffrey Shaman
In March, satellite sensors detected an enormous wave travelling east along the Equator below the surface of the Pacific Ocean. As it moved towards the South American coastline, the wave pushed up sea height and temperatures, while heating and moistening the atmosphere above. Towering thunderstorms developed, generating large-scale atmospheric ripples. These ripples quickly spread across the planet, altering temperature patterns, rainfall distribution, and the movement of major storm systems.
The El Niño spawned by that colossal wave has since warmed a portion of the central and eastern equatorial Pacific Ocean by more than 3°C above its historical average. Climate forecasts now indicate a greater than 80% chance that this natural climate phenomenon, which recurs every few years, will remain exceptionally strong for the rest of the year and could become the most powerful on record.
There are over two dozen climate models from agencies across the globe that forecast El Niño conditions, and they rarely agree. This year, however, they are remarkably aligned in predicting that El Niño conditions will persist well through the end of 2026. This high level of scientific consensus means that expected global impacts — torrential rainfall in some regions, drought and wildfires in others, and a rise in global warming — are certain to occur.
It also means that governments, businesses and communities can benefit from this unusually clear scientific foresight. There is still time to get ready.
Past El Niño events provide a clear blueprint of what lies ahead. Southern Africa and India are far more likely to experience reduced rainfall and drought, which may strain food supplies and disrupt hydropower generation. Dry conditions over Indonesia have already led to wildfires. Furthermore, the upcoming Southern Hemisphere summer is expected to bring severe heatwaves across Australia and major regions of Brazil.
Conversely, regions such as Kenya, eastern China, and the southern US are poised to receive far more rainfall than average. Current forecasts indicate a greater than 70% chance of above-normal precipitation across parts of the southeastern US between October and December, raising the risk of floods and landslides.
El Niño cycles are also linked to spikes in surface temperatures. Because oceans cover 70% of the Earth's surface, they absorb a large share of energy trapped by greenhouse gases. During an El Niño event, a significant portion of this stored oceanic energy is vented back into the atmosphere.
The last three major El Niño events — in 1997, 2015, and 2023 — were accompanied by sharp increases in surface temperature. Each of those years was the warmest in recorded history, and temperatures in subsequent years remained elevated. Indeed, the follow-up years (1998, 2016, and 2024) proved even warmer.
These elevated temperatures trigger more volatile weather. Heatwaves become longer and more intense, drought conditions spread, wildfire hazards escalate, and storm systems carry vastly more moisture, leading to frequent and severe downpours. The entire planet is affected, meaning 2027 weather could be rough for many of us.
The changes brought about by super El Niño will affect agriculture, energy and water security, ecosystems, supply chains, finance, travel and health. Governments, communities and businesses should assess their resilience to such disruptions and put resources and plans in place to respond.
We can assume the summer of 2027 will be unusually hot in the Northern Hemisphere. Given this, health care systems and hospitals should prepare for surges of patients with heat stroke, cardiovascular events and kidney disease. They’ll need proactive response strategies.
In the western US, the western Mediterranean, and Southeast Asia, wildfire risks will escalate. Preparation demands greater inter-agency coordination, increased funding, and better warning systems. Authorities can also introduce incentives for homeowners to safeguard properties by clearing dry brush and installing fire-resistant roofs.
Regional food insecurity may disrupt supply chains and lead to hoarding, price gouging and market instabilities. The UN Food Programme has already released funds to areas of Africa in anticipation of crop losses. Similarly, California has already deployed materials such as sandbags and pumps to combat flooding.
These El Niño forecasts are not abstractions of warming far in the future. They are concrete predictions of climate and weather conditions, some of which will be highly disruptive during the next 18 months. There is still time to prepare, plan and make our systems more resilient. Let’s get to work.