President Barack Obama called for a "comprehensive" bill during Wednesday's State of the Union address.

In his speech, Obama did not specifically mention the need for a market-based emissions cap. Some interpreted the omission as signaling that he would not actively pursue wide-ranging climate control legislation this year.

"Comprehensive climate change (legislation) means pricing carbon and setting a target for reduction," Senator John Kerry, a Democrat and one of three lawmakers leading difficult talks to hammer out a compromise climate bill, told Reuters.

Kerry strongly rejected the idea that progress had bogged down. "I just don't agree with that interpretation at all," he said, adding that Senate negotiations were "making headway."