In early 2018, a reform of the world’s largest functioning greenhouse gas emissions cap-and-trade system, the EU Emissions Trading System (ETS), was formally approved. The reform changed the main principles of the system by endogenizing the emissions cap. We show that the emissions cap is now affected by the allowance demand and is therefore no longer set directly by EU policymakers. As a consequence, national policies that reduce allowance demand can now reduce long-run cumulative emissions, which is not possible in a standard cap-and-trade system. Using a newly developed dynamic model of the EU ETS, we show that policies that reduce allowance demand can have substantial effects on cumulative emissions after the reform. Model simulations also suggest that the reform reduces long-run cumulative emissions and, to a lesser extent, reduces emissions in the short run. Even so, the reform has a small short-run impact on the currently large allowance surplus.

2018年初，正式批准了对全球最大的运行中的温室气体排放限额与交易系统（EU Ess Trading System，ETS）的改革。这项改革通过内化排放上限改变了系统的主要原则。我们表明，排放上限现在受配额需求的影响，因此不再由欧盟政策制定者直接设定。结果，减少配额需求的国家政策现在可以减少长期累积排放量，而这在标准的总量控制与交易系统中是不可能的。使用最新开发的欧盟排放交易体系动态模型，我们表明，减少配额需求的政策可能对改革后的累积排放产生重大影响。模型模拟还表明，这项改革减少了长期累积排放量，并在较小程度上减少了 在短期内减少排放。即使这样，这项改革对目前大量的盈余也有很小的短期影响。