The World’s Oceans Just Recorded Their Hottest July Ever — Here’s What That Actually Means

Did you know the ocean absorbs most of the extra heat trapped by greenhouse gases on Earth? That’s a big part of why what happens in the water matters just as much as what happens in the sky.

According to the EU’s Copernicus Climate Change Service, the average sea surface temperature across the globe’s non-polar waters hit 20.96°C in July — the highest ever recorded, edging past the previous record of 20.89°C set back in 2023. It was the joint second-warmest July on record overall, with El Niño conditions developing in the Pacific playing a real role in pushing numbers up.

Here’s why the ocean matters so much in all of this. Beyond covering most of the planet, the ocean produces about half of Earth’s oxygen and absorbs the majority of the extra heat generated by greenhouse gas emissions — acting as a massive buffer for the rest of the planet’s climate. When that buffer heats up, the effects ripple outward in a few specific, well-documented ways: seawater expands as it warms, which accounts for roughly a third of the sea level rise scientists have measured to date, and warmer surface waters mean longer, more intense marine heatwaves — the kind that have bleached coral reefs and stressed kelp forests and fisheries in recent years.

Europe felt this firsthand. Sea surface temperatures along the Atlantic coast and western Mediterranean hit record highs in July, and Western Europe recorded its hottest June and July on record, with England and Wales logging their driest July since rainfall records began 190 years ago. Samantha Burgess, strategic lead for climate at the European Center for Medium-Range Weather Forecasts, pointed to a mix of persistent high pressure and dry soils as the main drivers behind the extreme heat.

Why we’re covering this alongside the whale rescues and shark pups: understanding what’s happening to ocean temperatures is exactly the kind of context that makes the good news mean more. Every marine heatwave tracked, every degree measured, is data that helps scientists and conservationists know where to focus — the same kind of monitoring that let researchers catch this year’s Pacific “Blob” heatwave early, months ahead of where things stood a decade ago.

The ocean is sending a clear signal. The encouraging part is that more people than ever are actually listening, tracking, and building the tools to respond.

Sources: Copernicus Climate Change Service