BBC: Tiny fossils have helped refine the timing of the climate shift that gave rise to Antarctica’s remarkable Dry Valleys, a landscape akin to Mars. The famously ice-free terrain enjoyed more benign, tundra-like conditions 14 million years ago – but then flipped to the intensely cold setting seen today. Scientists tell a Royal Society journal that ancient lake-living shrimp-like creatures can pinpoint the big switch. The ostracods would not have coped with a harsh, dry …