Climate at the Crossroads

From a climate change perspective, 2015 had all the elements of a good drama: suspense, a surprise twist and a (somewhat) happy ending. It turned out to be the hottest year on record, but ended with new hope for turning down the thermostat: In December, nations are expected to enter into negotiations for a plan to cut greenhouse gas emissions. Throughout the year, a series of scientific revelations underscored its necessity — and overturned some long-standing assumptions.