The International Civil Aviation Organization (ICAO) set a cap for international aviation’s greenhouse gas (GHG) emissions at its 2020 level and established a market-based mechanism to help achieve that cap. Against that backdrop, this article identifies ICAO’s legal obligation to mitigate climate change by examining the international climate change treaties, ICAO’s constituent treaty, the Chicago Convention, and ICAO’s organizational practice. It finds that because ICAO is not a party to the climate change treaties and has a high degree of institutional autonomy, those treaties do not directly impose an obligation on ICAO. Although the Chicago Convention does not expressly mention the environment or climate change, ICAO’s member states interpreted the Convention and enlarged ICAO’s mandate under it to include the reduction or limitation of GHG emissions from international aviation so as to prevent dangerous climate change. This article finds that pursuant to Jan Klabbers’ recently developed theory of role responsibility, ICAO arguably has an obligation to carry out this important mandate, and its failure to do so, or failure to do so effectively, could constitute an internationally wrongful omission.

中文翻译：

---

晴朗的天空或前方的湍流？国际民航组织减轻气候变化的义务

国际民航组织（ICAO）为国际航空的温室气体（GHG）排放设定了2020年的上限，并建立了基于市场的机制来帮助实现这一上限。在这种背景下，本文通过研究国际气候变化条约，国际民航组织的组成条约，《芝加哥公约》和国际民航组织的组织惯例，确定了国际民航组织减轻气候变化的法律义务。它发现，由于国际民航组织不是气候变化条约的缔约国，并且具有高度的机构自主权，因此这些条约没有直接对国际民航组织施加义务。尽管《芝加哥公约》没有明确提及环境或气候变化，国际民航组织成员国对《公约》进行了解释，并扩大了国际民航组织的授权范围，包括减少或限制国际航空的温室气体排放，以防止危险的气候变化。本文认为，根据扬·克拉伯斯（Jan Klabbers）最近发展的角色责任理论，国际民航组织可以说有义务执行这项重要任务，而它未能做到或没有有效做到，可能构成国际不法行为的遗漏。