Arctic Sea Route access reshapes global shipping carbon emissions.

Climate-driven Arctic ice melt is opening the Arctic Sea Route (ASR), providing shorter paths for global trade while also raising critical environmental concerns. Here, we quantify the long-term carbon consequences of ASR access using a trade-integrated shipping emissions projection (TISEP) model that integrates trade scenarios, vessel routing, and climate policy pathways. Our results indicate that ASR use will increase global shipping emissions by 8.2% by 2100, with Arctic emissions rising from 0.22% to 2.72%. At the same time, environmental disparities in exposure to emissions will increase since Northeast Asia, Northern Europe, and North America will experience particularly large increases in emissions due to rerouted shipping flows. We evaluate three mitigation strategies and find that two ongoing strategies, the 2023 IMO Strategy on Reduction of GHG Emissions from Ships and the Green Corridor strategy, are insufficient to achieve emission targets in the Arctic, but a net-zero strategy featuring stricter fuel standards and regionally phased rollout could fully eliminate ASR-related emissions. These findings highlight the urgent need for more prospective actions to reduce shipping emissions, protect the Arctic environment, and advance global environmental justice as Arctic navigability increases.