The United Nations urged all countries on Tuesday to boost their early warning systems after confirming the onset of El Niño, warning that the climate phenomenon will bring above-average temperatures "nearly everywhere" and fuel more extreme weather. According to the World Meteorological Organization (WMO), there is an 80 percent probability that El Niño conditions will emerge between June and August, with a 90 percent chance thereafter.
Although the exact timing and peak strength of the upcoming El Niño remain uncertain, most forecast models indicate that it will be at least moderate, with a strong possibility of escalating further. Historically, El Niño events are classified as weak, moderate, strong, or very strong.
Humanitarian aid experts warn that this major climate phenomenon could severely exacerbate existing global crises and trigger new emergencies. In regions already battered by conflict and acute food insecurity, additional climate-related stressors are likely to destabilize communities and intensify needs.
Furthermore, extreme weather is causing severe water and arable land scarcity—factors increasingly linked to large-scale human displacement and localized conflict. Experts emphasize that these climate impacts disproportionately devastate the world’s most vulnerable populations.
To mitigate these risks, governments around the world, along with humanitarian organizations and sectors sensitive to climate change, such as agriculture, public health, energy, and water management, rely heavily on WMO’s El Niño Updates, the global authority on climate preparedness.
“This update matters because El Niño is a major driver of global weather and climate patterns,” WMO Secretary-General Celeste Saulo told reporters in Geneva on Tuesday.
“The footprint of an El Niño travels far beyond its origins in the Pacific Ocean, impacting agriculture, energy supplies, trade, water resources, supply chains, and livelihoods across entire regions.”
Throughout late April and mid-May, sea-surface temperatures in the crucial central-eastern Equatorial Pacific monitoring zone steadily climbed toward critical El Niño thresholds. Meteorologists point out that this surface warming is being fed aggressively from below by an invisible, massive reservoir of heat, with deep subsurface ocean temperatures spiking to more than 6°C above average.
This intense thermodynamic buildup is sparking deep concerns among weather agencies worldwide that the impending El Niño could unleash devastating weather extremes on vulnerable and unprepared communities across the globe.
Saulo noted that the last El Niño, in 2023-24, was one of the five strongest on record, playing a role in the record global temperatures registered in 2024.
“We understand El Niño; we can prepare much better for El Niño thanks to science and to the investment of many countries to be well prepared,” the WMO chief said.
“But on top of El Niño, you have extreme events and those extreme events are requiring more and more [investment].”
In the coming months, WMO and weather agencies worldwide will monitor conditions to inform the decision-making of governments, aid agencies, and other climate-sensitive sectors.
“Advance seasonal forecasts and early warnings are vital to save lives and cushion the impact on our economies and our communities,” Saulo stressed.
On average, El Niño occurs every two to seven years, and episodes typically last 9 to 12 months. It is a naturally occurring climate pattern associated with the warming of ocean surface temperatures in the central and eastern tropical Pacific. However, it takes place in a context of climate change caused by human activities.
The pattern generally begins to develop between March and June, reaching peak intensity between November and February. Impacts on global temperatures are typically most pronounced in the second year after development. According to WMO, even a moderate El Niño makes some weather and climate extremes more likely.
While there is no evidence—at least for now—that climate change increases the frequency or intensity of El Niño events, it can amplify their impacts because a warmer ocean and atmosphere provide more energy and moisture for extreme weather events, such as heat waves and heavy rainfall.
“The science is clear: El Niño is arriving on our doorstep in the coming months with 90 percent certainty. The world must treat it as the urgent climate warning it is,” said UN Secretary-General António Guterres, in a statement released Tuesday.
“El Niño conditions will pour fuel on the fire of a warming world,” he warned, added that the impacts will “hit even harder, travel even farther, and cross borders with devastating speed.”
“The only effective response is climate action equal to the crisis – ending the addiction to fossil fuels, accelerating the shift to renewables, protecting the most vulnerable, and delivering early warning systems for all,” he stressed.
Earlier this year, WMO issued one of its most urgent warnings to date, stating that the Earth’s climate system is more imbalanced now than at any other time in modern history. The WMO's State of the Global Climate 2025 report, released in March, paints a stark picture of a planet accumulating heat at an unprecedented rate due to record levels of greenhouse gases, leading to increasingly severe consequences.
Record-high concentrations of greenhouse gases in the atmosphere continue to break heat records on land and sea, with long-lasting consequences for humanity. The Earth’s climate is more imbalanced now than at any other time in recorded history. Between 2015 and 2025, the world experienced the 11 hottest years on record.