The last powerful El Niño phenomenon was accompanied by a series of temperature records, and scientists fear that warming seas promise even more extreme weather.
April this year became one of the hottest on record both on land and in the oceans. Against the backdrop of a new warming of the global ocean, scientists say that the powerful El Niño phenomenon could further heat the planet in the coming months.
In April 2026, the sea surface temperature in the oceans outside polar latitudes was the second highest on record, according to data from the EU's Copernicus Climate Change Service.
Globally, April also ranked third among the warmest on record: the average temperature was 1.43 °C above pre-industrial levels, dangerously close to the threshold of 1.5 °C set in the 2015 Paris Agreement.
This data fuels growing concerns that a new period of extreme global heat is on the horizon, and that unusually warm oceans will continue to drive climate anomalies.
Why is Sea Temperature Rising Again?
Sea surface temperature is one of the most indicative indicators of how much excess heat the planet is absorbing.
According to Copernicus, in April, the average sea surface temperature in significant parts of the World Ocean reached 21 °C - the second highest figure for this month. Only April 2024, during the last major El Niño episode, was hotter.
Particularly high values were recorded in the tropical part of the Pacific Ocean: record warm water extended from central areas to the western coasts of the United States and Mexico. Scientists characterized the situation as powerful marine heatwaves - a worrying signal that more heat is accumulating in the Earth's oceans, primarily due to human-induced climate change.
Study: Dangerous Droughts Caused by Heat are Rapidly Increasing
According to the Intergovernmental Panel on Climate Change, since 1970, the world's oceans have absorbed more than 90 percent of the excess heat trapped by greenhouse gas emissions. Warmer oceans intensify storms, damage marine ecosystems, and disrupt weather patterns across the planet.
According to Samantha Burgess, head of the climate division at the European Centre for Medium-Range Weather Forecasts, the April data demonstrates a "clear signal of sustained global warming."
"Sea surface temperatures were at record levels, marine heatwaves were widespread, Arctic sea ice extent remained significantly below normal, and Europe experienced sharp contrasts in temperature and precipitation," she stated.
"All of these are signs of a climate increasingly influenced by extreme weather."
What is 'Super El Niño'?
Scientists are currently closely monitoring signs of a potentially destructive phenomenon known as 'Super El Niño' forming in the second half of the year.
El Niño (translated from Spanish as 'the boy') is a natural oscillation of the climate system associated with abnormal warming of the surface of the Pacific Ocean. It typically leads to an increase in global temperatures and alters weather patterns worldwide, bringing drought to some regions and flooding to others.
ECMWF forecasts indicate that by autumn, water temperatures in the central Pacific near the equator could rise up to 3 °C above normal. In this case, the phenomenon would rank among the most powerful El Niño episodes on record.
Typically, researchers refer to 'Super El Niño' as an episode where Pacific Ocean temperatures rise at least 2 °C above average. However, this designation is not officially used by the National Oceanic and Atmospheric Administration (NOAA).
The last major El Niño episode in 2024 contributed to a series of global temperature records. Scientists fear that the new phenomenon, against the backdrop of ongoing climate warming, could lead to even more extreme weather.
Already in April, severe flooding hit several areas of the Arabian Peninsula, Iran, and Afghanistan, while drought conditions worsened in southern Africa. Tropical cyclones were forming in the Pacific Ocean.
A Split in Europe's Climate Picture
Last month, Europe effectively experienced two completely different Aprils. The southwest of the continent was much warmer than usual, with Spain recording the hottest April on record, while Eastern Europe experienced colder-than-normal weather conditions.
Overall, April ranked only tenth among the warmest on record across the continent, but this figure hides sharp regional disparities and recent trends.
A recent Copernicus report showed that at least 95 percent of Europe experienced above-normal temperatures in 2025. New data adds to the growing body of evidence that the climate crisis on the continent is accelerating.
