Reuters: The United States hopes to take the reins of international efforts to battle global warming next week with a meeting of major economies aimed at facilitating a U.N. pact to cut greenhouse gas emissions. President Barack Obama, a Democrat who took office in January, called the meeting last month to relaunch a process that began under his Republican predecessor, George W. Bush, whose commitment to curbing climate change was viewed with skepticism by much of the world. The stakes …