... Historical injustice aside, the Chinese also insisted that they should not be held responsible for the greenhouse gases they emit when producing goods for foreign consumers. But they refused to accept the logical implication of this view -- that the burden should fall on those foreign consumers instead, that shoppers who buy Chinese products should pay a "carbon tariff" that reflects the emissions associated with those goods' production. That, said the Chinese, would violate the principles of free trade.

Sorry, but the climate-change consequences of Chinese production have to be taken into account somewhere. And anyway, the problem with China is not so much what it produces as how it produces it. Remember, China now emits more carbon dioxide than the United States, even though its G.D.P. is only about half as large (and the United States, in turn, is an emissions hog compared with Europe or Japan). <...>

As the United States and other advanced countries finally move to confront climate change, they will also be morally empowered to confront those nations that refuse to act. Sooner than most people think, countries that refuse to limit their greenhouse gas emissions will face sanctions, probably in the form of taxes on their exports. They will complain bitterly that this is protectionism, but so what? Globalization doesn't do much good if the globe itself becomes unlivable.

It's time to save the planet. And like it or not, China will have to do its part.