The decarbonization of shipping has become an important policy goal. While integrated assessment models (IAMs) are often used to explore climate mitigation strategies, they typically provide little information on international shipping, which accounts for emissions of around 0.7 GtCO₂ yr⁻¹. Here we perform a multi-IAM analysis of international shipping and show the potential for decreasing annual emissions in the next decades, with reductions of up to 86% by 2050. This is primarily achieved through the deployment of low-carbon fuels. Models that represent several potential low-carbon alternatives tend to show a deeper decarbonization of international shipping, with drop-in biofuels, renewable alcohols and green ammonia standing out as the main substitutes for conventional maritime fuels. While our results align with the 2018 emission reduction goal of the International Maritime Organization, their compatibility with the agency’s revised target is still subject to a more definitive interpretation.

航运脱碳已成为重要的政策目标。虽然综合评估模型 (IAM) 通常用于探索气候缓解策略，但它们通常提供的有关国际航运的信息很少，国际航运的排放量约为 0.7 GtCO ₂ 年 ⁻¹ 。在这里，我们对国际航运进行了多 IAM 分析，并展示了未来几十年减少年排放量的潜力，到 2050 年减少高达 86%。这主要是通过使用低碳燃料来实现的。代表几种潜在低碳替代品的模型往往显示出国际航运更深层次的脱碳，其中直接生物燃料、可再生酒精和绿色氨脱颖而出，成为传统海运燃料的主要替代品。虽然我们的结果与国际海事组织 2018 年减排目标一致，但其与该机构修订目标的兼容性仍需更明确的解释。