This book analyses how sustainability affects internal decision-making within the European Union and its external relations in working towards achieving its long-term goal of a climate-neutral Europe by 2050. Applying the term "European environmental conscience" as the perception of environmental degradation leading to a growing public awareness of the issues, a notion of common responsibility, and European institutions dealing with these growing concerns, the book investigates its emergence as a lever for deeper European integration and in fostering a genuine European identity. Examining policy areas such as green finance, innovation policies, and foreign policy, it reveals the impact these concerns have for other policy fields. This book is of key interest to scholars and students of environmental economics and politics, sustainability governance, green finance, climate policy, energy policy, and more broadly, to European studies and international relations.