An exceptional rise in sea levels revealed

Montee eau Crédits SHOM, janvier 2012


Retracing variations in the sea level over the course of the Earth's history sheds light on past, current and future climates and their impacts. Thanks to samples taken from coral reefs off the coast of Tahiti, researchers from the Cerege(1) have reconstructed one of the major events of the last deglaciation: an exceptional rise in the sea level, associated with an ice break-up(2). The study, which has just been published in Nature (figures available), shows that this episode, many aspects of which remained controversial, began exactly 14,650 years ago and corresponds to a mean rise in sea levels of 14 m in under 350 years.

Moreover, contrary to previous assumptions, the Antarctic ice cap contributed greatly, to the tune of fifty percent, to this increase. This massive input of freshwater greatly disturbed the world's oceanic circulation, with consequent repercussions on the global climate. These results are also of great importance in view of the current and future rise in ocean levels. In fact, they bring to the fore the dynamic behaviour of the polar ice caps in response to an increase in temperature, a phenomenon that is still insufficiently taken into account in the GIEC's forecasts(3) for the period up to 2100.

Authors – Pierre Deschamps and Gaëlle Courcoux

The rest is available on IRD's site and on the INSU-CNRS site.

A scientific data sheet concerning this news item, produced by the IRD, is available here in pdf format.


This work benefitted, in particular, from the support of the Comer Foundation (USA), the European Science Foundation (ESF-EuroMARC), the European Community (Past4Future Project), the Collège de France, the CNRS and the IRD.


Notes :

(1) Centre Européen de Recherche et d'Enseignement en Géosciences de l'Environnement (IRD / Aix-Marseille Université / CNRS / Collège de France)

(2) break up of the ice caps.

(3) Intergovernmental group of experts on climate change

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