New York, March 14: Global Sea levels rose faster than anticipated in 2024, primarily due to the expansion of ocean water as it warms, NASA reported on Thursday. A NASA-led analysis found that last year’s rate of sea level rise was 0.59 centimetres per year, higher than the expected 0.43 centimetres per year, Xinhua news agency reported.
“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,” said Josh Willis, a sea level researcher at NASA’s Jet Propulsion Laboratory in Southern California.
The unexpected increase was attributed to an unusual amount of ocean warming, combined with meltwater from land-based ice, such as glaciers, NASA explained. In recent years, about two-thirds of sea level rise was driven by the addition of water from melting ice sheets and glaciers, with the remaining third attributed to thermal expansion of seawater.
However, in 2024, these contributions were reversed, with two-thirds of the rise coming from thermal expansion, according to NASA. “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 programmes and the Integrated Earth System Observatory at NASA Headquarters in Washington.
Since the satellite record of ocean height began in 1993, the rate of annual sea level rise has more than doubled. In total, global sea levels have risen by 10 centimetres since 1993, according to NASA.
The long-term record is based on observation from the ocean-observing satellites starting with TOPEX/Poseidon in 1992. The current ocean-observing satellite in that series, Sentinel-6 Michael Freilich, launched in 2020 and is one of an identical pair of spacecraft that will carry this sea level dataset into its fourth decade.
Its twin, the upcoming Sentinel-6B satellite, will continue to measure sea surface height down to a few centimetres for about 90 per cent of the world’s oceans.
IANS