The world’s oceans are heating up at an alarming rate, setting a new record in 2025. Scientists have found that over 90% of the heat from human-caused carbon pollution is absorbed by the oceans. This is a clear sign of the ongoing climate crisis, and it won’t end until we seriously cut down emissions.
Since 2000, almost every year has seen higher ocean temperatures. This rising heat leads to stronger hurricanes, heavier rainfall, and longer marine heatwaves, which harm ocean life. It also contributes to sea level rise, endangering millions of people living along coastlines.
Data on ocean temperatures has been collected since the mid-20th century. Experts believe the oceans are currently the hottest they’ve been in at least a thousand years, and they may be warming faster than at any time in the last 2,000 years. The atmosphere stores less heat and is influenced by natural cycles like El Niño and La Niña. For example, while temperatures in 2025 are expected to be among the highest on record, the planet shifted into the cooler La Niña phase last year.
Professor John Abraham from the University of St. Thomas explains, “Global warming is ocean warming.” For a true picture of how the Earth is warming, we need to look at ocean temperatures.
A recent study published in the journal Advances in Atmospheric Sciences examined data collected from various oceanic instruments. They measured the heat content in the top 2,000 meters of the ocean, where most heat is stored. The amount of heat absorbed is staggering—it’s over 200 times the electricity used globally.
Not all oceans are warming equally. In 2025, hotspots included the tropical Atlantic, North Pacific, and Southern Ocean near Antarctica. There’s significant concern that winter sea ice is collapsing there.
The North Atlantic and the Mediterranean are also showing signs of warming, becoming saltier and more acidic. This “ocean state change” is making marine ecosystems more fragile.
As Professor Abraham warns, as long as the planet keeps warming, ocean temperatures will rise. The future depends on our actions now. By cutting emissions, we can help ensure a more stable climate for everyone.
For more insight into climate conditions, check out the latest reports from NOAA and stay informed about how to take climate action.
