As the Senate Energy and Public Works Committee began hearings today on the Kerry-Boxer Clean Energy Jobs and American Act , the Senate version of climate and energy legislation, a CNN/Opinion Research poll shows 60% of respondents favor cap-and-trade , the central mechanism limiting greenhouse gas emissions. In a survey conducted October 16 to 18, 1,038 adults were asked: Under a proposal called cap and trade, the federal government would limit the amount of greenhouse gases that com