Global sea levels rose at an accelerated rate in 2024, driven by extreme ocean warming and melting land ice, according to a NASA-led analysis.
The annual rate of sea level rise jumped to 0.23 inches (0.59 cm), significantly higher than the expected 0.17 inches (0.43 cm).
“The rise we saw in 2024 was higher than we expected,” said Josh Willis, a sea level researcher at NASA’s Jet Propulsion Laboratory. “Every year is a little bit different – but what’s clear is that the ocean continues to rise and the rate of rise is getting faster and faster.”
A key reason for this acceleration is thermal expansion – when seawater expands as it warms.
In recent years, about two-thirds of sea level rise came from melting ice sheets and glaciers, while a third was due to thermal expansion.
But in 2024, those contributions flipped, with warming oceans accounting for two-thirds of the rise.
“With 2024 as the warmest year on record, Earth’s expanding oceans are following suit, reaching their highest levels in three decades,” said Nadya Vinogradova Shiffer, Head of Physical Oceanography at NASA.
Since satellite records began in 1993, global sea levels have risen by 4 inches (10 cm) and the rate has more than doubled over time.
NASA’s ongoing Sentinel-6 Michael Freilich satellite mission, along with its upcoming twin Sentinel-6B, will continue tracking sea surface height, measuring ocean levels down to a few centimeters for nearly 90% of the world’s oceans.
Heat enters the ocean in several ways, with most of it trapped near the surface due to temperature and density differences.
However, extreme winds and large ocean currents, such as those in the Southern Ocean, can disrupt this layering and push heat deeper. The massive movement of warm water during El Niño also plays a role, shifting heat across the Pacific and driving further warming effects.
As ocean temperatures continue to rise, so too will sea levels—reshaping coastlines, increasing flood risks and challenging communities around the world.
