Key U.S. Senate Democrats this week said it is unlikely that a comprehensive bill to curb greenhouse gas emissions will be voted on until next year.

The Senate Environment Committee approved a version of the cap and trade bill last week. But the legislation still faces strong revisions from moderate Democrats, particularly from senators on the Finance and Agriculture committees.

“It’s common understanding that climate-change legislation will not be brought up on the Senate floor and pass the Senate this year,” Senate Finance Chairman Max Baucus was quoted as saying in the Wall Street Journal.

Even climate bill champion Senator John Kerry, who last week said committees should have climate legislation processed by the end of the year, has since backed off such expectations. “I don’t want to create artificial deadlines which get in the way of our being methodical about this,” he told the press.