The President made the remarks in an Oval Office interview with a select number of reporters.
At a time when much of the world is mired in recession, Mr. Obama said, "We have to be careful about sending any protectionist signals."
He said that certain energy-intensive American industries--like steel, aluminum, paper and glass--had legitimate concerns about competition from developing nations and that he would seek to level the playing field in international negotiations.
But he warned that trade sanctions that are based on the extent to which other countries curb carbon dioxide emissions might be illegal and counterproductive.
"I don't know if tariffs are the way," he said.
Nevertheless, Obama praised the House bill and urged the Senate to take up the legislation, though he did not set a deadline.
White House adviser David Axelrod said today that he expects the Senate to take up healthcare reform before addressing the climate change bill.