Pressure is building on world leaders to increase their efforts to fight global warming. It’s coming to a boil this week at the United Nations. U.N. officials are corralling 35 to 40 world leaders behind closed doors to coax them to do more. There’s a deadline in just six weeks. That’s the big international climate conference in Scotland. And U.N. officials say they worry it might fail. This comes after President Joe Biden delivered them the same message last week. This summer has seen a drumbeat of devastating wildfires, floods, heat waves and hurricanes.