An anonymous reader quotes a report from the BBC: The world's oceans are hotter than ever recorded, new data suggests, as they suffer from human-caused climate change and the growing El Nino weather phenomenon. The average surface temperature of the planet's seas outside the polar regions hit 21.1C (70F) on Saturday, according to figures from the European Copernicus climate change service. That edges past the 21.09C recorded on three separate days in March 2024, and is far above average for the time of year. [...] The data is based on sea temperatures 10m (32ft 10in) below the surface, using measurements from buoys, ships and satellites, which are combined to produce a global estimate. While the margin of record is currently very small and any global estimate comes with uncertainties, scientists say its timing is particularly notable. Average worldwide sea temperatures tend to reach their yearly peak in March or April, which corresponds to the end of summer in the southern hemisphere -- and not in August. The southern hemisphere contains more of the planet's ocean surface than the northern hemisphere and so exerts a bigger influence on average sea temperatures. What is especially concerning to scientists is that the oceans are already so hot when the natural El Nino weather phenomenon is still some way off its expected peak. "The fact that we are already breaking records is an early indicator of how strong the El Nino is becoming," said Dr Jeremy Grist, senior research fellow at the National Oceanography Centre in Southampton. "All things being equal we might expect the ocean temperature record to be broken again in March [or] April 2027," he added.

Read more of this story at Slashdot.

A rapidly developing El Nino is already reaching record-setting levels for this time of year and is expected to intensify further over the coming months. "The El Nino has blossomed. It is off the charts. Usual measures of El Nino have blown past prior record levels in the period with good data, even though maximum effects are still several months in the future," writes renowned climate scientist James Hansen at Columbia University in New York in a newsletter sent today. Climate scientists disagree over whether it has already surpassed previous "super El Nino" events on every metric, but several say the signal is unprecedented in forecasts and could ultimately become the strongest modern event on record. New Scientist reports: There are different ways of measuring El Ninos, which occur when warm surface waters spread eastwards along the equator across the surface of the tropical Pacific Ocean. Hansen thinks the best measure is how much warmer than usual the upper 300 meters of the eastern tropical Pacific becomes. "Our preferred metric, the heat anomaly in the upper 300 meters of the Equatorial Pacific Ocean... already exceeds the 1997-98 super El Nino," he writes. [...] What's clear is that this developing super El Nino will soon exceed previous events on all measures. "I have never seen an El Nino signal this intense in our forecasts," [Adam Scaife at the Met Office, the UK's national weather service] said in a statement released today. "If the forecast is accurate... then 2026 will far exceed our recent experience of El Nino and its worldwide climate influences." While Hansen is comparing the developing super El Nino to other modern events for which we have direct temperature records, Hayley Fowler at Newcastle University in the UK thinks it could also exceed historical events suspected to be even larger. "The super El Nino evolving in the Pacific will likely be the biggest ever recorded, reaching or exceeding the levels of the 1877-1878 El Nino which caused widespread impacts, including famines and around 50 million deaths (3-4 percent of the global population at the time), mostly across Asia and South America," Fowler said in a statement.

Read more of this story at Slashdot.