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International shipping in a world below 2 °C

Nature Climate Change (2024)Cite this article

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Abstract

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.

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Fig. 1: Decarbonization challenges in the shipping sector.
Fig. 2: Global CO2 emissions and primary energy.
Fig. 3: International shipping CO2 emissions.
Fig. 4: Evolution of key indicators of energy and carbon intensity in international shipping over the century across models and scenarios.
Fig. 5: International shipping in the context of the global energy transition.

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Data availability

The underlying data are available via Zenodo at https://doi.org/10.5281/zenodo.10815601 (ref. 70). Source data are provided with this paper.

Code availability

The models are documented on the common IAM documentation website (https://www.iamcdocumentation.eu/index.php/IAMC_wiki). Some of them have published open-source code (for example, WITCH, https://github.com/witch-team/witchmodel). For a brief documentation of the models and main concepts, see Supplementary Sections 2 and 3.

References

  1. Faber, J. et al. Fourth IMO GHG Report (International Maritime Organization, 2021).

  2. International shipping. International Energy Agency https://www.iea.org/reports/international-shipping (2023).

  3. EEXI and CII—ship carbon intensity and rating system. International Maritime Organization https://www.imo.org/en/MediaCentre/HotTopics/Pages/EEXI-CII-FAQ.aspx (2019).

  4. EEXI—Energy Efficiency Existing Ship Index (DNV GL, 2021).

  5. Comer, B. & Carvalho, F. IMO’s Newly Revised GHG Strategy: What It Means for Shipping and the Paris Agreement (ICCT, 2023).

  6. Carvalho, F. et al. Prospects for carbon-neutral maritime fuels production in Brazil. J. Clean. Prod. 326, 129385 (2021).

    Article  CAS  Google Scholar 

  7. Vermeire, M. B. Everything You Need to Know about Marine Fuels (Chevron Marine Products, 2021).

  8. World bunker prices. Ship & Bunker https://shipandbunker.com/prices (2022).

  9. Maritime Forecast to 2050 (DNV, 2021).

  10. Englert, D. & Losos, A. Charting a Course for Decarbonizing Maritime Transport: Summary for Policymakers and Industry (World Bank, 2021).

  11. A Pathway to Decarbonise the Shipping Sector by 2050 (IRENA, 2021).

  12. Müller-Casseres, E., Edelenbosch, O. Y., Szklo, A., Schaeffer, R. & van Vuuren, D. P. Global futures of trade impacting the challenge to decarbonize the international shipping sector. Energy 237, 121547 (2021).

    Article  Google Scholar 

  13. Moss, R. H. et al. The next generation of scenarios for climate change research and assessment. Nature 463, 747–756 (2010).

    Article  CAS  Google Scholar 

  14. van Vuuren, D. P. et al. The representative concentration pathways: an overview. Clim. Change 109, 5–31 (2011).

    Article  Google Scholar 

  15. Clarke, L. et al. in Climate Change 2014: Mitigation of Climate Change (eds Edenhofer, O. et al.) Ch. 6 (IPCC, Cambridge Univ. Press, 2014).

  16. van Vuuren, D. P. et al. Energy, land-use and greenhouse gas emissions trajectories under a green growth paradigm. Glob. Environ. Change 42, 237–250 (2017).

    Article  Google Scholar 

  17. Gambhir, A. et al. Assessing the feasibility of global long-term mitigation scenarios. Energies https://doi.org/10.3390/en10010089 (2017).

  18. Fujimori, S. et al. SSP3: AIM implementation of Shared Socioeconomic Pathways. Glob. Environ. Change 42, 268–283 (2017).

    Article  Google Scholar 

  19. Kriegler, E. et al. Fossil-fueled development (SSP5): an energy and resource intensive scenario for the 21st century. Glob. Environ. Change 42, 297–315 (2017).

    Article  Google Scholar 

  20. Grubler, A. et al. A low energy demand scenario for meeting the 1.5 °C target and sustainable development goals without negative emission technologies. Nat. Energy 3, 515–527 (2018).

    Article  Google Scholar 

  21. Rogelj, J. et al. Scenarios towards limiting global mean temperature increase below 1.5 °C. Nat. Clim. Change 8, 325–332 (2018).

    Article  CAS  Google Scholar 

  22. Riahi, K. et al. Cost and attainability of meeting stringent climate targets without overshoot. Nat. Clim. Change 11, 1063–1069 (2021).

    Article  Google Scholar 

  23. van Soest, H. L. et al. Global roll-out of comprehensive policy measures may aid in bridging emissions gap. Nat. Commun. 12, 6419 (2021).

    Article  Google Scholar 

  24. Riahi, K. et al. in Climate Change 2022: Mitigation of Climate Change (eds Shukla, P. R. et al.) Ch. 3 (IPCC, Cambridge Univ. Press, 2022).

  25. van Beek, L., Hajer, M., Pelzer, P., van Vuuren, D. & Cassen, C. Anticipating futures through models: the rise of Integrated Assessment Modelling in the climate science–policy interface since 1970. Glob. Environ. Change 65, 102191 (2020).

    Article  Google Scholar 

  26. Guivarch, C. et al. in Climate Change 2022: Mitigation of Climate Change (eds Shukla, P. R. et al.) AIII (IPCC, Cambridge Univ. Press, 2022).

  27. Esmeijer, K., den Elzen, M. & van Soest, H. L. Analysing International Shipping and Aviation Emission Projections of IAMs (PBL, 2020).

  28. Sharmina, M. et al. Decarbonising the critical sectors of aviation, shipping, road freight and industry to limit warming to 1.5–2 °C. Clim. Policy 21, 455–474 (2021).

    Article  Google Scholar 

  29. Müller-Casseres, E. et al. Production of alternative marine fuels in Brazil: an integrated assessment perspective. Energy 219, 119444 (2021).

    Article  Google Scholar 

  30. Next generation of advanced integrated assessment modelling to support climate policy making. NAVIGATE https://www.navigate-h2020.eu/ (2023).

  31. Riahi, K. et al. The Shared Socioeconomic Pathways and their energy, land use, and greenhouse gas emissions implications: an overview. Glob. Environ. Change 42, 153–168 (2017).

    Article  Google Scholar 

  32. Transport sector CO2 emissions by mode in the Sustainable Development Scenario, 2000–2030. International Energy Agency https://www.iea.org/data-and-statistics/charts/transport-sector-co2-emissions-by-mode-in-the-sustainable-development-scenario-2000-2030 (2019).

  33. Hanssen, S. V. et al. The climate change mitigation potential of bioenergy with carbon capture and storage. Nat. Clim. Change 10, 1023–1029 (2020).

    Article  CAS  Google Scholar 

  34. Stenzel, F. et al. Irrigation of biomass plantations may globally increase water stress more than climate change. Nat. Commun. 12, 1512 (2021).

    Article  CAS  Google Scholar 

  35. Leblanc, F. et al. The contribution of bioenergy to the decarbonization of transport: a multi-model assessment. Clim. Change 170, 21 (2022).

    Article  Google Scholar 

  36. Lindstad, E., Stokke, T., Alteskjær, A., Borgen, H. & Sandaas, I. Ship of the future—a slender dry-bulker with wind assisted propulsion. Marit. Transp. Res. 3, 100055 (2022).

    Article  Google Scholar 

  37. Lindstad, E., Polic, D., Rialland, A., Sandaas, I. & Stokke, T. Reaching IMO 2050 GHG targets exclusively through energy efficiency measures. J. Ship Prod. Des. 39, 194–204 (2023).

  38. Chou, T., Kosmas, V., Acciaro, M. & Renken, K. A comeback of wind power in shipping: an economic and operational review on the wind-assisted ship propulsion technology. Sustainability 13, 1880 (2021).

  39. Feenstra, M. et al. Ship-based carbon capture onboard of diesel or LNG-fuelled ships. Int. J. Greenh. Gas. Control 85, 1–10 (2019).

    Article  CAS  Google Scholar 

  40. Ros, J. A. et al. Advancements in ship-based carbon capture technology on board of LNG-fuelled ships. Int. J. Greenh. Gas. Control 114, 103575 (2022).

    Article  CAS  Google Scholar 

  41. Rojon, I., Lazarou, N.-J., Rehmatulla, N. & Smith, T. The impacts of carbon pricing on maritime transport costs and their implications for developing economies. Mar. Policy 132, 104653 (2021).

    Article  Google Scholar 

  42. Pereda, P., Lucchesi, A., Diniz, T. & Wolf, R. Carbon Tax in the Shipping Sector: Assessing Economic and Environmental Impacts Working Paper No. 2023-04 (Department of Economics—FEA/USP, 2023); http://www.repec.eae.fea.usp.br/documentos/Pereda_Lucchesi_Diniz_Wolf_04WP.pdf

  43. UN Body Adopts Climate Change Strategy for Shipping (International Maritime Organization, 2018).

  44. Stopford, M. Maritime Economics (Routledge, 2009).

  45. United Nations Conference on Trade and Development in Review of Maritime Transport 2022 Ch. 1 (United Nations, 2022).

  46. Final consumption. Key World Energy Statistics 2021 (International Energy Agency, 2021); https://www.iea.org/reports/key-world-energy-statistics-2021/final-consumption

  47. BP Statistical Review of World Energy (BP, 2022); https://www.bp.com/content/dam/bp/business-sites/en/global/corporate/pdfs/energy-economics/statistical-review/bp-stats-review-2022-full-report.pdf

  48. Stefanakos, C. N. & Schinas, O. Forecasting bunker prices; a nonstationary, multivariate methodology. Transp. Res. C 38, 177–194 (2014).

    Article  Google Scholar 

  49. Lam, J. S. L., Chen, D., Cheng, F. & Wong, K. Assessment of the competitiveness of ports as bunkering hubs: empirical studies on Singapore and Shanghai. Transp. J. 50, 176–203 (2011).

    Article  Google Scholar 

  50. Comparison of Alternative Marine Fuels Report No. 2019-0567 (DNV GL, 2019).

  51. Gray, N., McDonagh, S., O’Shea, R., Smyth, B. & Murphy, J. D. Decarbonising ships, planes and trucks: an analysis of suitable low-carbon fuels for the maritime, aviation and haulage sectors. Adv. Appl. Energy 1, 100008 (2021).

    Article  CAS  Google Scholar 

  52. United Nations Conference on Trade and Development in Review of Maritime Transport 2022 Ch. 2 (United Nations, 2022).

  53. Propulsion Trends in Bulk Carriers (MAN, 2022); https://www.man-es.com/docs/default-source/marine/tools/propulsion-trends-in-bulk-carriers.pdf?sfvrsn=d851b1c6_14

  54. Propulsion Trends in Tankers (MAN, 2022); https://www.man-es.com/docs/default-source/marine/tools/propulsion-trends-in-tankers_5510-0031-03ppr.pdf?sfvrsn=399654ef_4

  55. Bouman, E. A., Lindstad, E., Rialland, A. I. & Strømman, A. H. State-of-the-art technologies, measures, and potential for reducing GHG emissions from shipping—a review. Transp. Res. D 52, 408–421 (2017).

    Article  Google Scholar 

  56. Sharmina, M., McGlade, C., Gilbert, P. & Larkin, A. Global energy scenarios and their implications for future shipped trade. Mar. Policy 84, 12–21 (2017).

    Article  Google Scholar 

  57. Net Zero by 2050 (International Energy Agency, 2021); https://www.iea.org/reports/net-zero-by-2050

  58. Roelfsema, M. et al. Taking stock of national climate policies to evaluate implementation of the Paris Agreement. Nat. Commun. 11, 2096 (2020).

    Article  CAS  Google Scholar 

  59. Rochedo, P. R. R. Development of a Global Integrated Energy Model to Evaluate the Brazilian Role in Climate Change Mitigation Scenarios. PhD thesis, Univ. Federal do Rio de Janeiro (2016).

  60. Rochedo, P. R. R. et al. Is green recovery enough? Analysing the impacts of post-COVID-19 economic packages. Energies 14, 5567 (2021).

  61. Waisman, H., Guivarch, C., Grazi, F. & Hourcade, J. C. The Imaclim-R model: infrastructures, technical inertia and the costs of low carbon futures under imperfect foresight. Clim. Change 114, 101–120 (2012).

    Article  Google Scholar 

  62. Prometheus model—model description.E3-Modelling https://e3modelling.com/modelling-tools/prometheus (2018).

  63. Pye, S. et al. The TIAM-UCL Model (Version 4.1.1) Documentation (Univ. College London, 2020); https://www.ucl.ac.uk/energy-models/sites/energy_models/files/tiam-ucl-manual.pdf

  64. Welsby, D., Price, J., Pye, S. & Ekins, P. Unextractable fossil fuels in a 1.5 °C world. Nature 597, 230–234 (2021).

    Article  CAS  Google Scholar 

  65. Bosetti, V., Carraro, C., Galeotti, M., Massetti, E. & Tavoni, M. WITCH—a world induced technical change hybrid model. Energy J. 27, 13–37 (2006).

  66. Colelli, F. P., Emmerling, J., Marangoni, G., Mistry, M. N. & De Cian, E. Increased energy use for adaptation significantly impacts mitigation pathways. Nat. Commun. 13, 4964 (2022).

    Article  CAS  Google Scholar 

  67. NDC Registry. United Nations Framework Convention on Climate Change https://unfccc.int/NDCREG (2023).

  68. Fricko, O. et al. The marker quantification of the Shared Socioeconomic Pathway 2: a middle-of-the-road scenario for the 21st century. Glob. Environ. Change 42, 251–267 (2017).

    Article  Google Scholar 

  69. IPCC: Summary for Policymakers. In Climate Change 2022: Mitigation of Climate Change (eds Shukla, P. R. et al.) (Cambridge Univ. Press, 2022).

  70. Müller-Casseres, E. et al. International shipping in a world below 2 °C. Zenodo https://doi.org/10.5281/zenodo.10815601 (2024).

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Acknowledgements

E.M.-C., F.L., M.v.d.B., P.F., O.D., H.N., R.D., T.L.G., I.S.T., I.T., J.E., L.B.B., D.P.v.V., A.G., L.D., J.P.-P., H.-S.d.B., N.T., P.R.R.R., A.S. and R.S. received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreements 821124 (NAVIGATE) and 821471 (ENGAGE). E.M.-C., R.D., L.B.B., A.S. and R.S. were also supported by the Brazilian National Council for Scientific and Technological Development (CNPq). F.L. has benefited from the support of the long-term modelling chair for sustainable development (Ponts ParisTech–Mines ParisTech) funded by ADEME, GRTgaz, Schneider Electric, EDF and the French Ministry of Environment. P.F. also received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement 101003866 (NDC-ASPECTS).

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Authors and Affiliations

  1. Centre for Energy and Environmental Economics (CENERGIA), Energy Planning Program (PPE), COPPE, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil

    Eduardo Müller-Casseres, Rebecca Draeger, Luiz Bernardo Baptista, Joana Portugal-Pereira, Alexandre Szklo & Roberto Schaeffer

  2. Ecole des Ponts ParisTech, CIRED, Nogent-sur-Marne, France

    Florian Leblanc

  3. CNRS, CIRED, Nogent-sur-Marne, France

    Florian Leblanc & Thomas Le Gallic

  4. PBL Netherlands Environmental Assessment Agency, The Hague, The Netherlands

    Maarten van den Berg, Isabela S. Tagomori, Detlef P. van Vuuren & Harmen-Sytze de Boer

  5. E3Modelling, Athens, Greece

    Panagiotis Fragkos, Ioannis Tsiropoulos, Anastasis Giannousakis & Nikolaos Tsanakas

  6. University College London (UCL), London, UK

    Olivier Dessens

  7. Delft University of Technology, Delft, The Netherlands

    Hesam Naghash

  8. Société de mathématiques appliquées et de sciences humaines (SMASH), Paris, France

    Thomas Le Gallic

  9. Centro Euro-Mediterraneo sui Cambiamenti Climatici, RFF-CMCC European Institute on Economics and the Environment (EIEE), Milan, Italy

    Johannes Emmerling & Laurent Drouet

  10. Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands

    Detlef P. van Vuuren

  11. IN+, Center for Innovation, Technology and Policy Research—Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal

    Joana Portugal-Pereira

  12. Research and Innovation Center on CO2 and Hydrogen (RICH Center) and Management Science and Engineering Department, Khalifa University, Abu Dhabi, United Arab Emirates

    Pedro R. R. Rochedo

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  1. Eduardo Müller-Casseres
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Contributions

E.M.-C., P.R.R.R., A.S. and R.S. conceptualized the study and coordinated the design of scenarios. F.L., P.F., D.P.v.V. and J.P.-P. provided key input for the research question and article structure. E.M.-C., R.D., L.B.B. and P.R.R.R. performed the COFFEE model runs. F.L. and T.L.G. performed the IMACLIM-R model runs. M.v.d.B., I.S.T., D.P.v.V. and H.-S.d.B. performed the IMAGE model runs. P.F., I.T., A.G. and N.T. performed the PROMETHEUS model runs. O.D. performed the TIAM-UCL model runs. H.N., J.E. and L.D. performed the WITCH model runs. E.M.-C., R.D., L.B.B. and P.R.R.R. organized and standardized the results. E.M.-C. led the writing process, to which P.F., D.P.v.V., J.P.-P., A.S. and R.S. also contributed considerably. All other authors engaged in review and editing. E.M.-C. and T.L.G. conceptualized and produced the main figures. E.M.-C. and A.S. edited the Article according to reviewer comments. E.M.-C. and R.S. were responsible for the executive coordination.

Corresponding author

Correspondence to Roberto Schaeffer.

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Nature Climate Change thanks Patricia Fortes, Paula Pereda and Runsen Zhang for their contribution to the peer review of this work.

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Extended data

Extended Data Fig. 1 Overview of the modelling strategy.

Categorization of energy carriers: Conv – conventional maritime fuels; Oilseed – oilseed-based biofuels; D-synt bio – drop-in synthetic biofuels; D-synt other – other synthetic drop-in fuels; AG-fos – fossil alcohols and gases; AG-bio – bio-alcohols and biogases; AG-synt – Synthetic alcohols and gases; H2/NH3 – Hydrogen and ammonia; Elec – electricity.

Supplementary information

Supplementary Information

1. Context. 2. Short description of global IAMs and their approach to international shipping. 3. Shipping and fuel production modelling across IAMs. 4. Comparison of adopted carbon budgets with the Sixth Assessment Report of the IPCC. 5. Detailed results for BECCS. 6. Fuel aggregation. 7. Detailed results for Europe.

Source data

Source Data Fig. 1

International shipping emissions. Energy intensity. Vessel survival rate. Average age of the merchant fleet.

Source Data Fig. 2

Global CO2 emissions indexed to 2020. Global primary energy across models and scenarios.

Source Data Fig. 3

International shipping activity indexed to 2020. International shipping emission variation in 2050 relative to 2020. International shipping emission variation in 2070 relative to 2020.

Source Data Fig. 4

Fleet energy intensity. Final energy emission factor. International shipping carbon intensity.

Source Data Fig. 5

Fossil share across models. International shipping final energy mix.

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Müller-Casseres, E., Leblanc, F., van den Berg, M. et al. International shipping in a world below 2 °C. Nat. Clim. Chang. (2024). https://doi.org/10.1038/s41558-024-01997-1

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