House Energy and Commerce Committee Chairman John Dingell says he will propose a “carbon tax” on the burning of fossil fuels only to show how unpopular it would be, AP reports.

“I sincerely doubt that the American people are willing to pay what this is really going to cost them,” Dingell said.

His proposal would boost the federal gas tax by 50 cents a gallon and establish a “double digit” tax on carbon dioxide emissions. The fuel tax is now 18.4 cents.