evidence: What they find out could have an impact on worldwide civilization within a few generations—especially in coastal regions. Ice cores may reveal whether Antarctica's western ice sheet melted fully the last time Earth's climate warmed to the temperatures the planet is predicted to reach in the next two centuries. If it did, it's likely to again, which would raise sea levels significantly enough to threaten many seaside cities. [...] "We would see much warmer temperatures and higher levels of sea salt reflected in the ice core chemistry if this location was hundreds of miles closer to the ocean in the past," Osterberg said. [...] When drilling an ice core at a remote site in Greenland in 2012, his team found out that a hurricane-strength storm was headed their way. Because their tents and equipment were high up on an unprotected, rocky ridge, the best defense would have been to move down into the valley. But they'd camped up high for a reason—warming temperatures in the region had been melting sea ice, which was driving many polar bears onto the land. The ridge was the best place to avoid them.