Back in the U.S., unusual weather patterns have seen record low temperatures in Rocky Mountain states and parts of the Pacific Northwest, while temperatures spiked to record highs along much of the Eastern Seaboard. Newark, New Jersey, saw thermometers top 80 Wednesday—the highest temperature ever recorded there in February. The wild weather came as the National Snow and Ice Data Center warned global warming has driven wintertime sea ice levels to the lowest levels seen since record-keeping began. January 2018 saw Arctic sea ice reach just 13 million square kilometers—an area 10 percent smaller than the average for recent decades. This week, temperatures in the Arctic rose by more than 45 degrees Fahrenheit above normal—with the world’s northernmost weather station in Greenland recording winter temperatures above freezing.