A dramatic rise in sea level occurred millions of years ago, according to new research

Four million years ago, rising temperatures and ice loss around the world may have pushed sea levels up to 16 meters above current levels, according to a new study that, according to scientists, will help us understand and predict the evolution of the coasts in the face of climate change. .

Describing their work in the journal Nature, scientists discovered and analyzed six geological formations in Artà Cave on the island of Mallorca, in the western Mediterranean. Seventy samples of phreatic overgrowth were taken from speleothems, mineral deposits that form on stalagmites and stalactites, found between 22.5 and 32 meters above modern sea level. Although the cave is located 100 meters from the shoreline, the analysis of the deposits suggests that they have been formed by an oceanic accumulation over the years, due to the rise in sea level who flooded the cave 3 to 4 million years ago.

Sea level increased at a time known as the Middle Piacenzian, when temperatures were 2 to 3 ° C (3.6 to 5.4 ° F) above pre-industrial levels, marking "the last time the Atmospheric CO of the Earth₂ was as high as today. At the highest level, the sea level might have been higher by more than 23 meters (74 feet) above current levels at the Pliocene climatic optimum, there are 4 million of them. years, when the average temperature of the planet exceeded 4 ° C (7.2 ° F) -the industrial levels.

"The changes in sea level in the Artà cave can be caused by melting and growth of the ice cap or by the uprising or subsidence of the island itself," said the researcher. Jacky Austermann in a statement.

Overall, the data can help clarify what our planet may look like, as rising temperatures and melting melting ice contribute to sea level rise around the world. The reconstruction of the icecap and sea level changes from the past, when the climate was warmer than today, provides insight into future predictions.

"We can use the knowledge gained from past warm periods to adjust the icecap designs that are then used to predict the future response of the ice sheet to current global warming," said Bogdan Onac, co-author of the ice cap. ;study.

Even if atmospheric CO₂ stabilizes at current levels, the authors note that the global level of the seas should still reach the levels observed previously, or even higher. The data indicate that ice caps are "very sensitive" to warming and provide important calibration targets for future ice sheet models.

"The binding models for sea-level rise due to increased warming mainly depend on actual measurements of past sea level," said author of the study, Victor Polyak. "This study provides very robust measurements of sea level heights during the Pliocene."

Although the volume and rate of ice melt remain a mystery, the authors believe that their work will allow future predictions to accurately measure sea level rise in the face of climate change caused by man. .