Reuters: The United States is asking for ideas about how to tackle global warming without raising expectations of breakthroughs in 2010 ahead of climate talks among the world’s top emitters in Washington on Sunday. A document obtained by Reuters on Friday listing U.S. questions to delegates from 16 other major economies shows the two-day talks will focus on the fate of U.N. climate talks, the non-binding Copenhagen Accord and the Kyoto Protocol. It does not answer key questions such as …