International shipping in a world below 2oC

Abstract

In recent years, the decarbonisation of international 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 around 0.75 GtCO2/yr. Here, we perform the first multi-IAM analysis of international shipping, drawing on the results of six global models. Results indicate the need for decreasing emissions in the next decades, with reductions up to 88% in 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 decarbonisation of international shipping, with drop-in biofuels, renewable alcohols and green ammonia standing out as the main substitutes of conventional maritime fuels.