We haven’t discovered the solution to climate change yet, but we’re pretty sure we’re getting warmer. At least, our oceans are. As greenhouse gas emissions continue to trap heat in Earth’s climate system, our oceans have absorbed much of the excess heat. Every few years, however, a natural climate phenomenon called El Niño shifts the distribution of heat, with impacts felt around the world.
As a consequence of climate change amping up the cycle’s worst effects, El Niño has taken over our newsfeed: scientists warn about it, politicians argue about it and the global community braces for it. But what is El Niño? And what do you need to know?
To begin, El Niño was first christened by Peruvian fishermen in the 1600s when they noticed periods of unusually warm water in the Pacific Ocean. In full, they named it El Niño de Navidad, or “the Christ Child,” due to it falling around Christmas time.
El Niño itself is a natural weather pattern that occurs roughly every two to seven years. It typically develops in the spring or summer and grows stronger in the fall before peaking in the winter. It represents the warm phase of the El Niño–Southern Oscillation (ENSO) cycle, which rotates between El Niño, its counterpart La Niña (the cool phase) and more neutral, day-to-day conditions. Under normal conditions, trade winds — the permanent east-west winds in Earth’s equatorial region — push warm surface water toward Southeast Asia and Australia. Upwelling subsequently causes cold, nutrient-rich water to rise along the west coast of South America. During El Niño, however, these trade winds weaken. Warm water is pushed back east, toward the west coast of the Americas. The accompanying shift in tropical rainfall and thunderstorm activity fundamentally alters atmospheric circulation.
The resulting impact is similar to dropping a boulder into a stream: the rock’s energy is quickly transferred to the stream on impact, sending violent ripples outwards, far from the sight of initial impact. With El Niño, the water is our atmosphere, and the ripples cause our planet’s jet streams to shift, disrupting weather patterns thousands of miles away.
This year’s cycle is remarkably strong. So strong that it has been referred to by some as a “super” or “Godzilla” El Niño. The World Health Organization for the first time declared this El Niño a health emergency, while scientists have warned that unusually strong El Niño seasons have historically been correlated with over 100,000 annual extra heat-related deaths worldwide. Looking at the charts, it’s easy to see why.
“El Niño and indeed the state of the global climate in 2026 gives new meaning to the phrase off the charts,” World Meteorological Organization Secretary-General Celeste Saulo said in a statement. “El Niño doesn’t add new heat to the planet. It releases heat from the ocean, which is the warmest ever measured. There is simply more heat available to release.”
True to Saulo’s point, El Niño has already given the contiguous United States its hottest summer on record this year and boosted Pacific hurricane activity with rare, damaging storms near Hawaii.
With El Niño’s warmer water, marine life off the Pacific coast is also affected. The weakening of the upwelling process under El Niño causes a lack of nutrients to be brought up from the ocean floor. This in turn leads fewer phytoplankton — the backbone of the marine foodweb — to be found off the coast, threatening the food sources of countless marine species. These species come under further stress when warmer waters attract competing tropical species, like yellowtail and albacore tuna, into areas that are normally too cold for them.
Simultaneously, El Niño keeps hurricanes away from the Atlantic, causing the Caribbean to be drier than usual. These droughts can cause regions worldwide to face increased food insecurity as crops begin to fail. In other regions, sustained flooding can cause similar damage. The World Food Program, for instance, warned that our current El Niño might push an additional 49 million people into acute food insecurity by the end of 2027, taking the total number to 274 million. Drier air is likely to cause Australia, Southeast Asia and Southern Africa to face increased wildfire risk, raising dangers to human life.
Disease rates are expected to rise as well. In Africa, cholera rates have already begun to rise, while areas in South America and the southern U.S. brace for respiratory illness and the spread of insect-borne illnesses as warmer weather increases the range of vector species. Flooding is also expected to bring water-borne illnesses as overflow sweeps into contaminants and destroys local preventive infrastructure.
Connecticut, however, will likely remain relatively tame and experience a more mild and wet winter. According to the U.S. Geological Survey, El Niño is expected to bring more frequent coastal storms and nor’easters to the Northeast, increasing the likelihood of heavy precipitation and localized flooding. Although warmer-than-average temperatures are likely to reduce overall snowfall, individual storms could still bring some snow depending on their origin and available pockets of cold air.
El Niño is a natural phenomenon, but our changing world has caused its worst effects to be exacerbated. As climate change continues to raise global temperatures, increasingly intense climate fluctuations carry consequences that we cannot afford to ignore. We cannot prevent El Niño. We can, however, band together as a global community to prepare for its effects, protect vulnerable communities and work to limit our own emissions to limit the impact of future El Niño events.