Global sea levels rise ‘unexpectedly’ in 2024: NASA

ISTANBUL

Global sea levels rose 0.23 inches (0.59 centimeters) in 2024, surpassing the expected 0.17 inches, according to NASA.

A NASA-led analysis published Thursday found that thermal expansion, the process of ocean water expanding as it warms, played a big role in the “unexpected” 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, director of physical oceanography programs at the US space agency.

NASA confirmed in January that Earth’s average surface temperature in 2024 was the warmest on record, with global temperatures last year at 1.28C (2.3F) above the agency’s 20th-century baseline.

In previous years, two-thirds of sea level rise resulted from meltwater from glaciers and ice sheets, while one-third came from thermal expansion. In 2024, however, those proportions flipped, with two-thirds of the rise attributed to thermal expansion, according to the analysis.

Josh Willis, a sea level researcher at NASA’s Jet Propulsion Laboratory, emphasized the accelerating trend.

“The rise we saw in 2024 was higher than we expected … The ocean continues to rise, and the rate is getting faster and faster,” he said.