"You are the fireman and the planet's on fire. And you don't pick up a hose," said Rep. Jay Inslee, D-Wash.
"You do nothing, your administration does nothing," Inslee said.
Johnson knew this reckoning was coming.
Despite his own promise to issue new regulations last year, despite a Supreme Court order 11 months ago for the EPA to act on greenhouse gasses, and despite the president's own order last May to have regulations in place this year, Johnson now says he needs more time to write the rules on limiting carbon dioxide, the most threatening greenhouse gas.
"We've got to do a lot of re-work to be able to put out an implementing regulation," he said.
Democrats simply were not buying it.
"They are not only sitting on the regulations, they are sitting on the fate of the planet," Rep. Ed Markey, D-Mass., said.
Democratic complaints against Johnson go beyond carbon dioxide.
Just this week Johnson set new ozone pollution rules much looser than his own science advisers said were necessary to protect public health.
His rules, estimates say, will cause an additional 6,000 deaths. He did the same thing, also overruling the scientists, when he set pollution limits on soot.
"We're all trying to work our way through this process," said Rep. Greg Walden, R-Ore.
Republicans are asking Democrats to take a breath on global warming. They fear if Johnson legally declares carbon dioxide a danger, thousands of American businesses, large buildings and hospitals, might need CO2 emission permits.
"If it does, then practically every business in every large facility is going to be subject to additional regulations," said Rep. Marsha Blackburn, R-Tenn.
Johnson insists that he is working away on carbon dioxide but with just 10 months left in the administration, Democrats charge nothing is forthcoming and that Johnson is working the clock.