Russia’s war against Ukraine has significantly impacted governance and international cooperation in the Arctic. Since February 2022 Western Arctic states have suspended most multilateral economic and scientific cooperation with Russia, and the Arctic Council, the region’s key intergovernmental forum, is currently unable to fulfil its role as an interface between science and politics. The resulting collapse of pan-Arctic climate research and environmental protection could have drastic consequences in the long term. Increased militarisation and resource extraction also have implications for security and stability in the region. Geopolitical tensions and a narrow focus on strategic interests may result in spillover effects on the Arctic region and further disregard for the concerns of indigenous populations. While the Arctic Council grapples with its current restraints, other cooperative frameworks, especially legally binding agreements, remain relevant. As well as looking at the practical consequences of the war for cooperation within the Arctic Council and beyond, this report analyses its effects on long-term Arctic dynamics and discusses possible ways of dealing with current challenges multilaterally without legimitising Russian aggression.