BALI, Indonesia – A U.N. climate conference adopted a plan Saturday to negotiate a new global warming pact.European and U.S. envoys dueled into the final hours of the two-week meeting over the European Union’s proposal that the Bali mandate suggest an ambitious goal for cutting industrial nations’ emissions – by 25 to 40 percent below 1990 levels by 2020. That guideline’s specific numbers were eliminated from the text, but an indirect reference was inserted instead.