Associated Press: The United States may miss a December deadline for committing to reduce its greenhouse gas emissions, but that should not block an international agreement on global warming, the chief U.S. negotiator said Wednesday. Specific pledges by industrial countries to cut carbon dioxide and other gases blamed for climate change is a key element of a U.N. treaty being negotiated by 190 nations. The talks are due to be completed at a major conference in Copenhagen before the end of the …