Fifty-six million years ago, Earth experienced an exceptional episode of global warming. Within 10,000 to 20,000 years, the average temperature increased by 5 to 8 degrees, only returning to its original level a few hundred thousand years later. Based on the analysis of sediments from the southern slope of the Pyrenees, researchers measured the impact of this warming on river floods and the surrounding landscapes. Their conclusions show that the consequences of such global warming may have been much greater than predicted by current climate models.