Here’s How Carbon Gets Priced Around the World

It’s an idea that’s been around for more than two decades: To slow climate change, make polluters pay for the damage they cause. Worldwide, more than 50 nations, states and cities have adopted what’s known as carbon pricing, an approach held up by environmentalists, politicians and even many oil companies as an elegant, free-market approach to slow global warming. It’s done either through a tax on each metric ton of carbon dioxide emitted or by creating a market to trade permits to pollute. Carbon prices of $40 or more per ton are crucial if the world is to meet greenhouse-gas reduction targets in the Paris agreement to halt climate change, according to scientists.

Here’s how carbon pricing varies around the world: