Who pays after Copenhagen?

Who should pay for CO2 emitted when products are made? Consumers or the factory?
If you buy an MP3 player made in China, should you pick up the bill for making the factory cleaner - or should the polluter pay? And if one country's standards are easier than those in other countries, how do you prevent manufacturing migrating there?
Plus, the benefits of Iceland's crash - knitting through the "kreppa".