Harvard economist and former Reagan adviser Martin Feldstein says Obama’s cap-and-trade plan to limit global warming poses a serious threat to the global economy.

“There is a serious danger the international adoption of cap-and-trade legislation to limit carbon-dioxide emissions will trigger a new round of protectionism,” Feldstein writes in the New Scotsman.

“If an international agreement to impose a cap-and-trade scheme is adopted in Copenhagen, the countries there should also agree that there will be no attempt to introduce offsetting tariffs that would ultimately threaten our global system of free trade.”

A better idea, Feldstein says, is levying a tax on companies that emit greenhouse gases during production or that sell products that increase gas levels.

“Such a tax would cause firms to adopt techniques that reduce emissions, as long as the cost of doing so is less than the tax they would have to pay,” Feldstein says.

“A carbon tax causes each firm and household to respond to the same cost of adding to the atmosphere.”

Such a levy would also reduce the overall tax bill because it would involve fewer administrative costs, Levy notes.

The U.S House of Representatives passed, by a narrow margin, a massive energy bill that most notably includes a cap-and-trade program to reduce carbon dioxide emissions and allegedly curb global warming.

The Heritage Foundation, the Brookings Institution, and the National Black Chamber of Commerce all found that the bill will have devastating economic impacts, the Heritage Foundation reports, causing significant losses in employment and gross domestic product (GDP).