Paris Climate Pact: Too Little, Too Late?

When 195 nations clinched the Paris Agreement in December, it was heralded by some as a monumental achievement—the beginning of a process that would roll back the poisonous fruit of humankind's shortsightedness. Others viewed it as too little, too late.

As officials converged on the United Nations for the signing Friday, ominous reports in the four months since have buttressed the doubters: Global warming may hit geological hyperspeed in decades. NASA is projecting that 2016 will break the annual heat record for the third year running; Greenland's ice sheet is experiencing springtime melt weeks earlier than average; and much of West Antarctica is at risk of slipping into the Southern Ocean by 2100, adding a meter to global sea levels. Coastal cities home to millions of people may be underwater during the lifetimes of those born today.