According to the analyses carried out by two researchers and published in the journal « Nature », the differences between current estimates and the actual sea level would be about 0.3 m on average, and could even reach several meters in some places.
It is a threat to tens of millions of people around the world and yet rising sea levels may have been underestimated. In any case, this is the conclusion of a study published on Thursday 5 March in the prestigious scientific journal Nature.(New window) The authors of this study argue that estimates of sea level today are wrong, reduced by an average of 30 centimetres and even, in places, by as much as several metres.
According to the two Dutch researchers, specialists in the subject, sea levels have been misestimated and with them, the risks caused by rising sea levels. This is particularly the case in Southeast Asia and the Pacific, with a deviation of one meter to 1.5 meters on average. These « errors » are also observed in Latin America, on the American West Coast, in the Caribbean, in Africa, and in the Middle East.
Up to 132 million more people at risk
The authors screened nearly 400 scientific articles published between 2009 and 2025 on coastal risks and water levels. These studies are essentially based on theoretical models, and not on real measurements, and without taking into account tides, winds or currents. « These models give you the surface of the oceans in a calm situation, without disturbances, » summarizes one of the authors. This does not correspond to the reality on the ground. Hence the discrepancies between current estimates and more precise satellite observations, analysed in this new study. The authors even call for a re-evaluation and updating of the methodology of all studies on coastal risks.
If we underestimate the current level, we also underestimate the risks of rising oceans and the actions to be taken to adapt. The rise in sea levels, caused by global warming, is causing flooding, submersion and coastal erosion, all of which are already threatening tens of millions of people around the world and the very existence of certain countries, particularly archipelagos in the Pacific.
The authors have done the math: with their new measures, which have yet to be confirmed, up to 132 million more people are at risk of falling below sea level by the end of the century, in a particularly pessimistic scenario of global warming.
source : franceinfo
