Several climate centres said last month that El Niño, a natural climate pattern characterized by the warming of ocean surface temperatures that drives temporary spikes in global surface temperature, is likely to form during the summer months and persist into 2027.—Sea surface temperatures approached historic highs once again in March, paving the way for the return of a warming weather pattern known as El Niño later this year.The average sea surface temperature last month was 20.97C, the second-highest value on record for the month, according to the European Union Copernicus Climate Change Service’s (C3S) monthly bulletin published Friday. The climate monitor said this reflects “a likely transition toward El Niño conditions.”

Several climate centres, including the National Oceanic and Atmospheric Administration, said last month that El Niño is likely to form during the summer months and persist through the end of 2026 and potentially longer, with a one-in-three chance of becoming “strong” in the winter months.

El Niño is a climate phenomenon related to the warming of sea surface temperatures in the central-east equatorial Pacific. During an El Niño event, the east-to-west trade winds die, keeping warmer than the normal air in the eastern and central parts of the tropical Pacific. The associated warming in the central and eastern tropical Pacific leads to increased temperatures and opposing weather patterns around the world, such as severe droughts in places like Australia and Southeast Asia and heavy floods in parts of the US and East Africa.

A man lies down and wears a cooling patch on his forehead during a humid heatwave in Hong Kong.
A man lies down and wears a cooling patch on his forehead during a humid heatwave in Hong Kong. Photo: Kyle Lam/hongkongfp.com

The past two such events – in 2014-16 and 2023-24 – brought record heat around the world that fueled further global temperature increase. 2024 went down as the hottest year on record due to a combination of long-term human-caused climate change and a strong El Niño weather pattern. Now, its return increases the chances of another record warm year – likely to be 2027.

The highest sea surface temperature for March was recorded in 2024 during the last El Niño event, C3S also said on Friday.

Record March

Globally, last month was the fourth-warmest March on record at 1.48C above pre-industrial levels, according to the European climate monitor.

Regionally, however, temperature trends varied. Europe saw its second-warmest March on record as well as drier-than-average conditions, following an exceptionally wet and cold February. Part of the US were hit by a record-breaking heatwave and drier-than-average conditions, with the country as a whole experiencing its warmest March on record, like Finland. Meanwhile Hong Kong recorded its second-warmest March following the warmest winter in the city’s history. And in the Arctic, both the annual maximum sea ice extent and monthly average for March were the lowest on record.

For Carlo Buontempo, C3S Director, the data “tells a sobering story … of a climate system under sustained and accelerating pressure.”

The past 11 years have been the warmest ever recorded, compared to the average before the Industrial Revolution, with the last three years including all of the top three warmest.

The burning of coal, natural gas, and oil for electricity and heat is the single-largest source of global greenhouse gas emissions. These are the primary drivers of global warming as they trap heat in the atmosphere and raise Earth’s surface temperature. Global fossil fuel consumption has more than doubled in the last 50 years, and so have emissions, reaching record high levels in 2025.