Europe’s cap-and-trade system effectively puts a price on carbon emissions by requiring emitters to buy permits on the open market. Trouble is, the price has fluctuated wildly, peaking at €30 in 2008 and slipping to just €8 last year, making it hard to plan and undercutting incentives for green investment. Hence the attraction of the British Conservative Party’s new proposal to tax power plant emissions when the free market price of carbon permits fell below a predetermined level. Why didn’t we think of that?






