Global Shipping Emissions from a Well-to-Wake Perspective: The MariTEAM Model.

Diogo Kramel,Radek Lonka,Helene Muri,Evert A. Bouman,YoungRong Kim,Anders H. Strømman,Jørgen B. Nielsen,Anna L. Ringvold,Sverre Steen

doi:10.1021/acs.est.1c03937

Abstract

Improving the robustness of maritime emission inventories is important to ensure we fully understand the point of embarkment for transformation pathways of the sector toward the 1.5 and 2°C targets. A bottom-up assessment of emissions of greenhouse gases and aerosols from the maritime sector is presented, accounting for the emissions from fuel production and processing, resulting in a complete “well-to-wake” geospatial inventory. This high-resolution inventory is developed through the use of the state-of-the-art data-driven MariTEAM model, which combines ship technical specifications, ship location data, and historical weather data. The CO2 emissions for 2017 amount to 943 million tonnes, which is 11% lower than the fourth International Maritime Organization’s greenhouse gas study for the same year, while larger discrepancies have been found across ship segments. If fuel production is accounted for when developing shipping inventories, total CO2 emissions reported could increase by 11%. In addition to fuel production, effects of weather and heavy traffic regions were found to significantly impact emissions at global and regional levels. The global annual efficiency for different fuels and ship segments in approximated operational conditions were also investigated, indicating the need for more holistic metrics than current ones when seeking appropriate solutions aiming at reducing emissions.

Highlights

As a consequence of the increasing demand for maritime transportation, emissions could increase proportionally
We present the well-to-wake emissions for the MariTEAM model based on 2017 activity, followed by a comparison with other bottom-up assessments
The most recent studies to assess emissions for international and global shipping have been published by Johansson et al.[10] that estimated 831 million tonnes of CO2 for the year 2015 and Faber et al.[2] that calculated 1064 million tonnes for the year 2017

Summary

Introduction

As a consequence of the increasing demand for maritime transportation, emissions could increase proportionally. Despite being one of the most efficient freight modal options in terms of emissions per tonnage transported per kilometer,[1] estimations by Faber et al.[2] indicate that the sector could be responsible for around 2.9% of total anthropogenic carbon dioxide (CO2) emissions, 11% of sulfur oxides (SOX), and 15% of nitrogen oxides (NOX) in 2018. For example, agriculture or energy, were to adopt more stringent mitigation policies, the relative contribution to total anthropogenic emissions from the maritime sector could increase substantially unless action is taken. The current ambitions involve cutting emissions by at least 50% by 2050 compared to 2008, while, at the same time, pursuing efforts toward zero emissions by 2100 if not sooner.[3] strategies to mitigate other emissions (NOX, SOX, black carbon) are being adopted (see, e.g., ref 4)

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