Oceans set July heat record as El Niño looms

Global oceans reached their hottest July on record, with an average sea-surface temperature of 20.96C outside the polar regions—beating 2023’s high and about 1.47C above pre-industrial levels—partly driven by developing El Niño conditions. Western Europe also had its hottest June–July, fueling heatwaves and drought that stressed water supplies and spurred wildfires, while the UK faces lower river levels and ongoing heat and drought risks. Warming seas contribute to sea-level rise through thermal expansion and amplify marine heatwaves, underscoring climate-change impacts and the risk of more extreme conditions ahead.