Record Ocean Temperature Recorded Amid Strong El Niño Conditions

Scientists have recorded the highest temperature ever measured in the world’s oceans, as climate change combines with a powerful El Niño in the tropical Pacific. The global average sea-surface temperature reached a record 70 degrees Fahrenheit on August 22, according to Europe’s Earth observation agency Copernicus, which has been tracking this metric daily since 1979. The previous single-day record was measured in March 2024. Samantha Burgess, strategic lead for climate at Copernicus’ European Center for Medium-Range Weather Forecasts, stated, "El Niño is adding heat to the system, but it is doing so on top of decades of human-driven warming." She added, "As ocean temperatures continue to rise, the risks to marine ecosystems and coastal communities also increase." Higher ocean temperatures contribute to sea level rise and increase the likelihood of extreme weather events, as warmer water transfers more heat and moisture to the atmosphere, intensifying storms and heat on land. Additionally, warmer oceans have a reduced capacity to absorb carbon dioxide. Record temperatures have already been measured in isolated areas of the world’s oceans, including the western Mediterranean Sea and the Earth’s poles, driven mainly by human-made climate change. Copernicus expects this trend to continue, with ocean temperatures now being intensified by El Niño. The August record is particularly concerning because global ocean temperatures are typically highest in March and April, after the Austral summer, according to Copernicus.