Global sea level rose faster than expected in 2024, according to NASA analysis
Climate change was a major driver to an unexpected level of sea level rise in 2024, according to a new NASA analysis.
Global sea levels rose 0.23 inches in 2024, satellite records show, compared to the predicted 0.17 inches expected for the year.
"The rise we saw in 2024 was higher than we expected," said Josh Willis, a sea level researcher at NASA’s Jet Propulsion Laboratory, in a statement. "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."
The majority of the difference between predicted and actual sea level rise was attributed to thermal expansion -- or the ocean waters expanding as they warm, researchers said.
An unusual amount of ocean warming, combined with meltwater from land-based ice such as glaciers, led to the increase of sea level rise last year, according to NASA.
About two-thirds of sea level rise in recent years has resulted from the melting of ice sheets and glaciers, with a third coming from thermal expansion, according to NASA. In 2024, those metrics flipped, with two-thirds of the rise attributed to expanding ocean water and one-third attributed to contributions from melting ice.
"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 programs and the Integrated Earth System Observatory at NASA.
The rate of annual sea level rise has more than doubled since the satellite record began in 1993 -- with sea levels rising at least 4 inches since then, according to NASA.
Sea levels have risen between 8 inches and 9 inches since 1880, according to the National Oceanic and Atmospheric Administration.
Human-amplified climate change is the primary cause for present-day rising sea levels, climate research shows.
Heat from the ocean's surface has slowly making its way down into cooler waters deeper into the sea, according to NASA. The massive movement of water during El Niño can also result in vertical movement of heat throughout the ocean's layers.
