The Senate began what is expected to be a weeklong, contentious debate Monday over legislation to combat global warming by mandatory reductions in carbon dioxide and other greenhouse gases. Senators voted 74-14 to proceed to the bill, but immediately it became clear Republican opponents were not going to make it easy. A request by Democrats to begin considering substantive changes in the bill was blocked by GOP opponents until Wednesday at the earliest. Senate Majority Leader Harry Reid of Nevada promised a thorough debate that will probably last through the week, if not longer. He said it’s clear that ‘global warming is real’ and Congress must act. But supporters of the bill acknowledged it will be difficult - perhaps impossible - to overcome a certain GOP filibuster threat against the legislation, meaning congressional action on global warming will probably be decided in the next Congress and by the next president. Many of the GOP senators who voted to debate the issue have said they are opposed to the bill. The Senate measure, which has wide Democratic and some Republican support, would cap U.S. emissions of carbon dioxide and other greenhouse gases, cutting them by 18 […]