Oceans just hit their hottest year ever (again)
A global team of scientists found that Earth's oceans soaked up more heat in 2025 than any previous year on record.
Their study, published January 9, 2026, shows our seas are warming faster than ever—something that impacts everyone.
Ninth year of record-breaking ocean heat
Ocean heat jumped by 23 zettajoules in 2025, making it the ninth year in a row to break records.
About one in six parts of the ocean saw all-time high temperatures, and a third ranked among their top three warmest years.
This matters because oceans absorb over 90% of the extra heat from greenhouse gasses we put into the atmosphere.
Why it matters for people and marine life
Hotter oceans mean stronger storms, heavier rain, and more flooding—especially for people living near coasts.
Marine heatwaves are lasting longer too, which hurts fisheries and sea life.
Plus, some regions like the tropics and Mediterranean are seeing waters get more acidic and less oxygenated—a tough combo for creatures trying to survive there.