EU’s Cap and Trade Works. Don’t Screw It Up: Michael Bloomberg

Few policies have done more to combat climate change than the European Union’s emissions trading system. By putting a price on carbon dioxide — currently about €70 per metric ton — it has given companies throughout the bloc a powerful incentive to invest in going green.

Europe’s leaders should stand by it — and improve it — rather than bowing to industry pressure to walk away from it.

Cap-and-trade systems, in which the government sets the quantity of allowable emissions and the market determines the price, have proved effective. The EU’s system is the world’s largest: The greenhouse gas output of ...