This week, President Obama stood in front of the Brandenburg Gate in Berlin and declared that “the effort to slow climate change requires bold action.” Some in Congress say we need to take such bold action now by taxing carbon dioxide.

But according to a Heritage Foundation analysis of the Boxer–Sanders carbon-tax bill, such a global warming mitigation policy would cost Americans dearly:

The carbon tax is just another progressive “sin tax” that, as it turns out, would hurt everyone who uses energy or needs it to run their businesses or buys things that require energy in order to be made.

The only thing bold about a carbon tax is how much it would cost Americans and how little the environmental benefits they would gain in return. Even if America stopped all carbon emissions—no cars, trains, or planes; no factories, homes, or businesses that run on anything other than nuclear electricity; no manufacturing of plastics, which use oil as a feedstock, and so on—the global temperature would decrease by 0.08 degrees Celsius by 2050.

The science is far from settled on the connection between carbon dioxide emissions and climate sensitivity, the role carbon plays or doesn’t, if global warming is even problematic, or how data fits into broader climate history. Global average temperatures have plateaued for the past 16 years while carbon dioxide levels have continued to climb.

It is not denial or cowardice to question interpretation of climate data, studies, and methodology. That is how the scientific method is supposed to work. So until scientists better understand how and why the climate is changing, politicians should have no business boldly regulating carbon dioxide emissions.