Climate change is hot. From the pope’s encyclical to the upcoming United Nations conference in Paris, leaders are debating how to slow and eventually stop the warming of our planet.
We economists think we have an answer: put a price on carbon dioxide and the other gases driving climate change. When emissions are free, businesses, consumers, and governments pollute without thinking. But put a price on that pollution and watch how clean they become.
That’s the theory. And it’s a good one. But translating it from the economist’s whiteboard to reality is challenging. A carbon price that works well in principle may stumble in practice. A real carbon price will inevitably fall short of the theoretical ideal. Practical design challenges thus deserve close attention.
To help policymakers, analysts, and the public address those challenges, Eric Toder, Lydia Austin, and I have published a new report, “Taxing Carbon: What, Why, and How,” on putting a price on carbon.
- Lawmakers could put a price on carbon either by levying a tax or by setting a limit on emissions and allowing trading of emission rights. These approaches have much in common. Politically, however, a carbon tax is on the upswing. Cap and trade failed in 2010, while interest in taxing carbon is growing, including three bills in Congress and endorsements from analysts of diverse ideological stripes.
- Carbon prices already exist. At least 15 governments tax carbon outright, and more than 25 have emissions trading systems. Those efforts have demonstrated that the economists’ logic holds. If you put a price on carbon, people emit less.
- Figuring out the appropriate tax rate is hard. The Obama administration estimates that the “social cost of carbon” is currently about $42 per metric ton. But the right figure could easily be double that, or half. That uncertainty is not a reason to not tax carbon. But it does mean we should maintain flexibility to revisit the price as new evidence arrives.
- Taxing carbon could reduce the need for regulations, tax breaks, and other subsidies that currently encourage cleaner energy. Rolling back those policies, in particular EPA regulations for existing power plants, may make policy sense and will likely be essential to the politics of enacting a carbon tax. But the details matter. Rolling back existing policies makes more sense with a carbon tax that’s high and broad, than with one that’s low and narrow.
- By itself, a carbon tax would be regressive: low-income families would bear a greater burden, relative to their incomes, than would high-income families. We can reduce that burden, or even reverse it, by recycling some carbon revenue into refundable tax credits or other tax cuts focused on low-income families.
- By itself, a carbon tax would weaken the overall economy, at least for several decades. That too can be reduced, and perhaps even reversed, by recycling some carbon revenue into offsetting tax cuts, such as to corporate income taxes.
- Unfortunately, there’s a tradeoff. The most progressive recycling options do the least to help economic growth. And the recycling options that do the most for growth would leave the tax system less progressive.
- A global agreement on carbon reductions would be preferable to the United States acting alone. Given the nation’s size and contribution to global emissions, a unilateral tax would make a difference, but would damage the competitiveness of some US industries. Special relief for these sectors could reduce the benefits of the tax, but may be necessary both practically and politically.
A carbon tax won’t be perfect. Done well, however, it could efficiently reduce the emissions that cause climate change and encourage innovation in cleaner technologies. The resulting revenue could finance tax reductions, spending priorities, or deficit reduction—policies that could offset the tax’s distributional and economic burdens, improve the environment, or otherwise lift Americans’ well-being.
The challenge is designing a carbon tax that delivers on that potential. We hope our new report helps elevate what will surely be a heated debate.