The world is experiencing a string of intense weather, from the polar vortex in the north to a cyclone near south-east Australia, as the latest data show the global temperatures that contribute to extremes continue to linger near record highs.
Scientists had expected the La Niña cooling phenomenon in the Pacific to ease rising temperatures, after the global average reached more than 1.5C above the pre-industrial level in 19 of the past 20 months.
But the cooling cycle’s influence on the southern ocean has been weak. Last month was the third-hottest February on record at 13.36C, or 1.59C above the pre-industrial level, the EU’s Earth observation agency Copernicus reported, and sea ice cover was at an all-time minimum.
“The long-term prognosis for Arctic sea ice is grim as the region continues to rapidly heat up and can only be saved with rapid and massive cuts to greenhouse gas emissions that will also limit the growing severity of weather extremes and long-term sea level rise across the world,” said Richard Allan, professor of climate science at University of Reading.
The average sea surface temperature was 20.88C in February, the second-highest value on record for the month after the same period in 2024.
Samantha Burgess, strategic lead for climate at the European Centre for Medium-Range Weather Forecasts, said the most recent monthly data showed a continued “streak of record or near-record temperatures observed throughout the last two years”.
Scientists have long warned of more extreme weather because of rising temperatures. Tropical Cyclone Alfred is on course to hit parts of the east coast of Australia much farther south than such storms typically land, while Japan is suffering its worst wildfires in decades.
At the same time, the disruption of the polar vortex — a large band of cold, rotating air that keeps the colder air nearer the poles — is expected to unleash freezing weather across North America later this month, with parts of the UK and Europe also expected to experience severe cold.
A “collapse” of the polar vortex occurs when the layer between 10 and 50km above the Earth’s surface heats up to 50C in less than two days, disrupting the normal circulation of cold air around the poles. Within weeks, this can affect the shape of the jet stream, the band of air that circles the globe, allowing cold air to spill down.
Much of the US experienced cold in February after a polar vortex disruption then contributed to storms across the midwest and north-east.
By contrast, the south-western US and Mexico, as well as northern Chile and Argentina, Western Australia and the Arctic experienced above-average temperatures in February, Copernicus said.
The World Meteorological Organization said on Thursday that the weak La Niña cycle that emerged in December was likely to be brief, with a 60 per cent probability that it will shift back to neutral between March and May.
While sea temperatures had cooled in the tropical Pacific region, they remained “unusually high in many ocean basins and seas”, Copernicus said.
“The heating is so fast,” said Stefan Uhlenbrook, director of hydrology, water and cryosphere at the WMO. “The changing climate is reflected in the ocean temperature and that leads to more melting of sea ice.”
Climate Capital
Where climate change meets business, markets and politics. Explore the FT’s coverage here.
Are you curious about the FT’s environmental sustainability commitments? Find out more about our science-based targets here
