I. The Arctic Environment -- Introduction to the Arctic -- The Arctic Marine Environment -- Environmental Governance in the Marine Arctic -- Arctic Indigenous Peoples and the Challenge of Climate Change -- II. Impacts & Activities in the Marine Arctic -- Status and Reform of International Arctic Fisheries Law -- Status and Reform of International Arctic Shipping Law -- Understanding Risks Associated with Offshore Hydrocarbon Development -- III. Improving Marine Governance -- Impacts Assessments and the New Arctic "Geo-Environment" -- Pan-Arctic Marine Spatial Planning: An Idea whose Time has come -- Marine Protected Areas as a Tool to Ensure Environmental Protection of the Marine Arctic: Legal Aspects -- IV. Opportunities for Transatlantic Cooperation -- EU-US Cooperation to enhance Arctic Marine Governance -- List of relevant Treaties, Instruments, and Agreements. The Arctic region plays an important role in regulating the world's climate and is also highly impacted by climate change, with average temperatures rising almost twice as fast as the rest of the world and sea ice melting much faster than previously predicted. These rapid changes will have significant impacts on human activity in the region and on the Arctic marine environment. This book draws on the results of the 2008-2009 Arctic TRANSFORM project, funded by the European Commission's Directorate General of External Relations, which engaged experts in a transatlantic discussion on the roles of the European Union and United States in light of the Arctic's changing climate and political and legal complexities. The book addresses the significant changes and developments in the marine Arctic, with descriptions and recommendations reflecting the current governance environment. A comprehensive overview of environmental governance and sustainable development in the Arctic is created. Chapters explore impacts and activities by sector, looking at fisheries, shipping, and offshore hydrocarbon in the Arctic and at policy options and strategies for improving marine governance in the region. A particular focus is given to the roles of the European Union and United States and opportunities for cooperation to enhance Arctic environmental governance.