The United States on Tuesday unveiled a plan to slash emissions of the greenhouse gas methane from oil and gas operations as part of its strategy to crack down on climate change, drawing cautious support from both environmental groups and drillers. The announcement coincided with the U.N. climate conference in Glasgow, Scotland, where the United States, the world’s second-largest greenhouse gas emitter, is seeking to reclaim leadership on the world stage by demonstrating tangible steps to curb emissions at home. […]