High-resolution mapping of Southern Ocean shipping emissions reveals policy-critical hotspots and post-pandemic rebound.

Antarctic shipping emissions are currently unregulated despite occurring in a sensitive environmental and geopolitical context. While previous studies have estimated tourism-related emissions, they lack the vessel type and spatial resolution necessary for effective mitigation strategies. This study integrates high-resolution Automatic Identification System (AIS) data with power-based modelling to quantify CO2 emissions from all ship classes operating in the Southern Ocean between 2019 and 2022. The findings reveal that ships operating south of 60°S emitted 0.63 million tonnes of CO2, with icebreakers (43.9 %), passenger vessels (28.7 %), and fishing ships (16.3 %) as the dominant contributors. Emissions were concentrated in the Antarctic Peninsula (60 %) and the Ross Sea (10 %), both critical biodiversity zones. The COVID-19 pandemic led to a 98 % reduction in tourism emissions in 2020-2021, while fishing ships remained largely unaffected, underscoring the sector's resilience to external disruptions. Four nations-the United States, Russia, Norway, and China-accounted for about 48 % of total emissions, highlighting disparities in polar operational footprints. These findings underscore the need for coordinated policy interventions, including region-specific emission regulations and strengthened clean fuel mandates under the IMO Polar Code, with the Antarctic Treaty System (ATS)-facilitated collaboration to advance national legislative and regulatory alignment-measures collectively aimed to align Antarctic shipping practices with Sustainable Development Goals (SDGs).