The paradox of polar ice sheet formation solved
The beginning of the last glacial period was characterized in the Northern hemisphere by major accumulation of snow at high latitudes and the formation of a huge polar ice sheet. For climatologists this was paradoxical, since snowfall is always associated with high humidity and relatively moderate temperatures. Now, a French team coordinated by MaríaFernanda Sánchez-Goñi, a researcher at EPHE working in the 'Oceanic and Continental Environments and Paleoenvironments' Laboratory (CNRS/Universités Bordeaux 1 & 4) has solved this paradox. By analyzing sediment cores dating from 80 000 to 70 000 years ago, the researchers have shown that during this period water temperatures in the Bay of Biscay remained relatively high, whereas temperatures in mainland Europe gradually fell. Carried northwards by wind, the humidity released by this thermal contrast appears to have caused the snowfall that formed the polar ice sheet. Their work was published on the Nature Geoscience website on September...