Steve Cochran and David Kreutzer talked about the Senate debate this week on a "cap and trade" bill intended to lower emissions of carbon dioxide and gases that contribute to global warming, and responded to telephone calls and electronic mail. The bill would cap emissions of carbon dioxide and other gases that scientists say contribute to global warming at 19 percent below current levels by 2020 and 71 percent lower by 2050. Utilities and industrial polluters could reduce emissions or "trade" part of their pollution level with others businesses with lower-level pollution. Sponsors estimate that the bill would reduce total domestic emissions by as much as 66 percent. The Environmental Defense Fund is one of the key groups that has been working on this bill.