So much has been invested in clean energy that there can be no rolling back of moves to end carbon emissions, US climate envoy John Kerry has said. Mr Kerry noted that if countries deliver on promises to phase out polluting fossil fuels, the world can limit average global warming to 1.5C, better than the worst case scenarios. “We’re in a very different place than where we were a year ago, let alone two and three years ago,” Mr Kerry said in an interview with The Associated Press. “But we’re not doing everything we said we’d do,” he said, after...