Bradford Plumer summarizes what we can learn from Europe's climate foibles:

The EU cap-and-trade system suffered a slew of early mishaps, but the United States has been watching and learning, and we should be able to avoid most of those fumbles. What's more, now that the problems have been ironed out, Europe's cap genuinely appears to be working, spurring companies to become more energy-efficient and making meaningful cuts in emissions. That said, the China factor is still huge: Europe obviously can't stop global warming all by itself, and there's no substitute for an international treaty.

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