Climate change exacerbates nuclear risks in the Arctic. But while climate change is widely recognized as a threat multiplier in the Arctic, regional governance has not yet adapted to this new reality. Climate change, geopolitical competition, and nuclear risk are typically treated as separate policy challenges, managed by separate institutions with different mandates. : Climate change exacerbates nuclear risks in the Arctic. Rather than expanding the Arctic Council’s mandate to encompass military security, the Arctic states should instead focus on closing the governance gap between climate change, geopolitical competition, and nuclear risks.