The average rise in global ocean levels was 0.76 centimeters between 2022 and 2023, a “significant jump” compared to other years, due to both El Niño and climate change, it said. NASA on Thursday.
Ocean levels have risen on average by 9.4 cm since 1993, according to these data based on satellite observations.
The main culprit is climate change, which involves the melting of ice (ice caps, glaciers), but also the expansion of the oceans as a result of heat absorption.
The rise in sea level is occurring more and more rapidly: its rate has more than doubled between 1993 (0.18 cm per year) and currently (0.42 cm).
“The current pace means we are on track to add another 20 cm to the global ocean level by 2050,” Nadya Vinogradova Shiffer, leader of the team responsible for this file at NASA, said in a statement.
This will “increase the frequency and consequences of floods across the world,” she stressed.
Between 2022 and 2023, the observed increase amounts to pouring a quarter of Lake Superior, the largest of the Great Lakes, into the oceans.
This increase represents a little less than four times the level observed the previous year (+ 0.21 cm between 2021 and 2022). That year, the Nina phenomenon was at work.
“During La Niña, rain that normally falls in the oceans instead falls on land, temporarily removing water from the oceans,” explained Josh Willis, a researcher on the subject at NASA.
But “during El Niño years, a lot of the rain that normally falls on land ends up in the ocean, which temporarily raises ocean levels,” he added.