In 2024, Ocean Levels Surged Higher and Faster Than Anticipated

[Article déjà publié le 20 mars 2025]

An ocean climb record in 2024

In 2024, the level of the oceans increased faster than expected, reaching an elevation rate of 0.59 centimeter per year, against 0.43 centimeters anticipated by scientists. This unprecedented increase was revealed by an analysis carried out by NASA, which has followed the evolution of sea level thanks to satellite observations since 1993. According to Josh Willis, researcher at the Jet Propulsion Laboratory, “the ocean continues to climb, and the rhythm of this elevation is accelerating”. The American agency thus confirms an alarming trend, observed over the decades: since the start of satellite statements, the average level of the seas has been raised by 10 centimeters.

This acceleration is largely due to thermal expansion of water. According to NASA and the American agency Noaa, 2024 has become the hottest year ever observed. Thus, with heat, water expands and occupies more space. This directly causes the level of the ocean level. Until recently, the melting of glaciers was the first cause of this elevation. However, in 2024, this trend changed. From now on, thermal expansion represents two thirds of the rise in the level of the seas. As for the melting of ice, it only contributes to a third party.

The impact of global warming on elevation of sea level

The rapid elevation of sea level is one of the direct manifestations of global warming. The heat accumulated on the surface gradually infiltrates the depths of the ocean, contributing to the phenomenon of thermal expansion. This effect is amplified by the El Niño phenomenon, which moves large hot water from the Western Pacific to the central and eastern Pacific. This redistribution of heat modifies the structure of the oceans and promotes the rise of water.

Since 1993, the data from the Topex/Poseidon satellites, then Sentinel-6 Michael Freilich, show a continuous acceleration of the rise of the oceans. NASA also provides for the pursuit of these measures with the Sentinel-6b satellite, which will analyze the height of the oceans with a precision of a few centimeters out of 90% of the seas of the globe. According to the echoes, experts believe that the rise in sea level continues as long as greenhouse gas emissions are not significantly reduced.

What consequences for coastal areas?

The populations living by the sea are on the front line in the face of the rapid rise in the level of the oceans. In Florida, India, Bangladesh or the Netherlands, millions of people risk being exposed to recurring floods and submersion of certain coastal areas. The phenomenon is particularly worrying for the small island states of the Pacific and the Indian Ocean, which see their territories nibbled year after year by the rise in waters.

Infrastructure by the sea, such as ports, roads and coastal buildings, are also in danger. According to NASA, the rise in ocean level already aggravates the exceptional tides. Certain urban areas thus become difficult to live. In the long term, effective measures will have to be taken. Many cities will have to review their organization and imagine new protections. They could for example build dikes or relocate the most vulnerable populations.

The studies carried out by NASA and other scientific organizations therefore come to the same conclusions. The rise in ocean level accelerates due to global warming. If nothing changes, the consequences will be severe for nature, infrastructure and populations. These upheavals will then impose significant challenges in the decades to come.