International climate policy risk spillovers occur when expected changes to climate policy stringency in one country affect expected climate policy stringency in another country. We develop an event study procedure to identify such spillovers in emissions trading systems, specifically examining the impact from the United States (US) to the European Union (EU). Distinguishing between policy events likely to reduce US commitment to climate action (‘brown events’) and those likely to increase it (‘green events’), we find that the average brown US policy event is associated with an anticipated increase in future EU carbon permit supply, leading to a cumulative 7.1% drop in EU carbon prices over the event window. Conversely, green US policy events are linked to an expected decrease in future EU permit supply, resulting in a cumulative 4.7% rise in EU carbon prices. These findings suggest that financial markets anticipate EU regulators to align with the direction of US climate policy. Our results underscore the significance of regulatory risk spillovers in global climate policy coordination.

中文翻译：

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美国气候政策风险的全球溢出效应：来自欧盟碳排放期货的证据


当一个国家气候政策严格性的预期变化影响到另一个国家的预期气候政策严格性时，就会发生国际气候政策风险溢出效应。我们制定了一个事件研究程序来识别排放交易系统中的此类溢出效应，特别是研究从美国 （US） 到欧盟 （EU） 的影响。区分可能降低美国气候行动承诺的政策事件（“棕色事件”）和可能增加气候行动承诺的政策事件（“绿色事件”），我们发现，美国平均棕色政策事件与未来欧盟碳许可供应的预期增加有关，导致欧盟碳价格在事件窗口期内累计下跌 7.1%。相反，绿色美国政策事件与未来欧盟许可证供应的预期减少有关，导致欧盟碳价格累计上涨 4.7%。这些发现表明，金融市场预期欧盟监管机构将与美国气候政策的方向保持一致。我们的结果强调了监管风险溢出在全球气候政策协调中的重要性。