The world is starting to heat up again, say British scientists, raising speculation that a 15-year slowdown in the rate of global warming could be coming to an end. A pause in the rate of global temperature rises since the late 1990s has baffled climate scientists and led some to question whether man-made climate change was a serious problem. But last year was the warmest on record, according to the UN’s World Meteorological Organisation, and scientists at the UK’s Met Office say both this year and 2016 are shaping up to be just as hot.