"China is enormously dependent on access to advanced-country markets — a lot of the coal it burns can be attributed, directly or indirectly, to its export business — and it knows that it would put this access at risk if it refused to play any role in protecting the planet.
More specifically, if and when wealthy countries take serious action to limit greenhouse gas emissions, they’re very likely to start imposing “carbon tariffs” on goods imported from countries that aren’t taking similar action. Such tariffs should be legal under existing trade rules — the World Trade Organization would probably declare that carbon limits are effectively a tax on consumers, which can be levied on imports as well as domestic production. Furthermore, trade rules give special consideration to environmental protection. So China would find itself with strong incentives to start limiting emissions."
In my opinion: Article XX of GATT does indeed allow us to unilaterally impose tariffs on China. I'd suggest that there should be a ramped approach. First, we should acknowledge that dangerous climate change has come early and we are already suffering damages. The growth in Federal crop and flood insurance payouts is owing to the effects of climate change. Instead of increasing premiums, we should use climate damage tariffs to cover this increase. That amounts to a pretty small tariff, but it firmly establishes the liability connection. Non-Annex I countries (as listed in the Kyoto Protocol) are becoming the main contributors to cumulative emissions just as climate change has turned dangerous, that makes their emissions the cause of dangerous climate change. An accident of timing? Yes. But deliberately increasing emissions, as China is doing, eliminates safe harbor as well.
This small tariff could be used as a stepping stone to larger tariffs imposed cooperatively with other Annex I countries if China does not turn around. The larger tariffs could be used to assist with adaptation costs in countries with low per capita emissions where vulnerability to dangerous climate change is high. Lack of a clear funding mechanism for this sort of thing has been a sticking point at climate negotiations. This would essentially get funds from those who are causing the damage.