New York Times: SCIENTISTS have often been accused of exaggerating the threat of climate change, but its becoming increasingly clear that they ought to be more emphatic about the risk. The year just concluded is about to be declared the hottest one on record, and across the globe climate change is happening faster than scientists predicted. Science is conservative, and new claims of knowledge are greeted with high degrees of skepticism. When Copernicus said the Earth orbited the sun, when Wegener said the continents...