Environment News Service: The head of the United Nations scientific climate panel spoke with U.S. lawmakers Wednesday, encouraging them lead the world in cooling the overheated planet. “We really don’t have a moment to lose,” said Rajendra Pachauri, chair of the UN Intergovernmental Panel on Climate Change, IPCC. The massive reductions in greenhouse gas emissions needed to avoid serious disruptions to Earth’s climate system are impossible without U.S. leadership, Dr. Pachauri told members of the …