Republicans warn world that Obama U.N. plan could be undone

By Valerie Volcovici WASHINGTON (Reuters) - The Obama administration's plan for U.N. climate change talks encountered swift opposition after its release Tuesday, with Republican leaders warning other countries to "proceed with caution" in negotiations with Washington because any deal could be later undone. The White House is seeking to enshrine its pledge in a global climate agreement to be negotiated Nov. 30 to Dec. 11 in Paris. It calls for cutting greenhouse gas emissions by cl