The oceans were colder than we thought

A team of EPFL and European researchers has discovered a flaw in the way past ocean temperatures have been estimated up to now. Their findings could mean that the current period of climate change is unparalleled over the last 100 million years. According to the methodology widely used by the scientific community, the temperature of the ocean depths and that of the surface of the polar ocean 100 million years ago were around 15 degrees higher than current readings. This approach, however, is now being challenged: ocean temperatures may in fact have remained relatively stable throughout this period, which raises serious concerns about current levels of climate change. These are the conclusions of a study conducted by a team of French researchers from the French National Center for Scientific Research (CNRS), Sorbonne University and the University of Strasbourg, and Swiss researchers from the Swiss Federal Institute of Technology in Lausanne (EPFL) and the University of Lausanne. The study has just been published . "If we are right, our study challenges decades of paleoclimate research," says Anders Meibom, the head of EPFL's Laboratory for Biological Geochemistry and a professor at the University of Lausanne. Meibom is categorical: "Oceans cover 70% of our planet. They play a key role in the earth's climate. Knowing the extent to which their temperatures have varied over geological time is crucial if we are to gain a fuller understanding of how they behave and to predict the consequences of current climate change more accurately." Content of oxygen-18 - How could the existing methodology be so flawed?