SEA ICE MELT
In late February 2018, temperatures at the North Pole reached an unprecedented 2 C — 30 degrees above normal. The cause? An intense storm had injected a wave of heat into the Greenland Sea that trickled throughout the Arctic. Since 1980, Arctic warming events such as this have been happening more often, and with greater intensity and duration. This is tied to the retreat and thinning of sea ice, shown here, which exposes open water and releases heat into the atmosphere. For more than a decade, ships have easily navigated the once famously ice-infested southern route of the Northwest Passage, which is now ice-free in the summer. Experts estimate that if greenhouse gases continue to build at their current rate, Arctic summers will be completely ice-free by 2040.