This article synthesizes key insights from recent transport decarbonization reports to outline a sustainable future. It highlights technological advancements, challenges, and opportunities in transitioning to a decarbonized transport sector.
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Current State of Transport Decarbonization
The transportation industry accounts for approximately 24% of global energy-related carbon emissions, making it a critical area for decarbonization efforts. The sector includes various modes such as road transport, aviation, shipping, and rail, each with unique challenges and opportunities for reducing emissions.1
In recent years, significant progress has been made in decarbonizing land transport, particularly urban mobility. Policies promoting electric vehicles (EVs), improvements in public transport, and infrastructure development for active mobility (walking and cycling) have reduced emissions in urban areas.
However, road freight, shipping, and aviation remain in the early stages of decarbonization and require coordinated action across industry ecosystems to mobilize resources for research, development, and pilot demonstrations that can be scaled up for broader implementation.2
How Can Global Transport Systems Be Decarbonized?
Aviation
The aviation industry, responsible for 2.5% of global carbon emissions in 2022, faces unique challenges in decarbonization due to technical hurdles with jet fuel replacement, low industry profit margins, and complex stakeholder dynamics.
The International Civil Aviation Organization (ICAO) projects that advancements in technology and operations could reduce emissions by up to 33% by 2050 compared to business-as-usual scenarios. In addition, sustainable aviation fuels (SAF) could meet 100% of international jet fuel demand by 2050, achieving a 63% emissions reduction, albeit requiring substantial investments and policy support.
The Clean Skies for Tomorrow coalition is exploring multiple SAF pathways, including hydrogenated esters from waste oils and gasification processes from forestry residues.
Significant technological advances are needed for complete decarbonization, especially for long-haul electric aviation.2
Land transport
Land transport can be decarbonized by leveraging existing and emerging technologies and behavioral changes, targeting an 85% reduction in CO2 emissions through technological solutions and the remaining 15% through behavioral shifts like increased teleworking and sustainable commuting.
It can be accomplished by achieving 100% electric vehicle sales by 2035 in major markets such as China, Europe, Japan, and the USA, focusing on light-duty vehicles, urban buses, and trucks.
Urban planning can support this through multimodal hubs and transit-oriented developments to enhance public transit, cycling, and walking. Meanwhile, strategic financial and supportive policy measures can accelerate this transition by aiming for 75% zero-emission sales for new light-duty vehicles by 2030 and a complete transition to zero-emission vehicles by 2035.
Shipping
Decarbonizing shipping requires accelerated R&D and cross-industry collaboration to develop zero-carbon vessels and green hydrogen technology. Operational improvements can reduce emissions by 30-50%, but full decarbonization relies on zero-carbon fuels like green ammonia.
By 2030, international shipping should aim for 5% propulsion energy from zero-carbon fuels, while domestic shipping should target 15% in developed nations, catalyzing a broader transition.
To meet Paris Agreement targets, the International Maritime Organization (IMO) must enforce strict 2023 deadlines for operational standards and zero-emission fuels, supported by freight purchasers committing to zero-carbon freight goals and accepting premium payments.
Technological Developments Accelerating Decarbonization
Electric vehicles (EVs)
The transition to electric and hydrogen fuel-cell vehicles is central to the decarbonization of road transport. EVs, powered by increasingly green electricity grids, offer significant GHG savings compared to internal combustion engine vehicles.
Major manufacturers like Audi and Daimler are halting R&D on internal combustion engines, while Volkswagen is converting plants to produce only electric vehicles.2
Alternate fuels
Biofuels
Biofuels, including biodiesel and bio-jet fuel, are being developed as sustainable alternatives to fossil fuels. Although biofuels can help reduce emissions, their sustainability is subject to overestimations, and biomass availability remains a concern. Developing advanced biofuels from non-food biomass and waste materials offers a more sustainable pathway, but scaling up production remains challenging.
A LIFE project in France developed a prototype to produce 5000 liters of biodiesel daily from used cooking oil, funded by a €1.5 million EU grant. This biodiesel fuels public transport in a northern French city, showcasing a sustainable energy solution.1
Sustainable aviation fuels (SAFs)
Sustainable aviation fuels, made from biofuels, recycled carbon aviation fuels, or synthetic fuels, offer potential pathways for decarbonizing the aviation sector. Several countries have mandated SAF adoption, with the EU considering a regional mandate and the UK promoting SAF commercialization through the Jet Zero Council. Commercially, Airbus is developing 'ZEROe Hydrogen' aircraft, targeting hydrogen-powered planes by 2035.
Wind propulsion and green ammonia
The shipping industry is embracing new technologies like wind propulsion and zero-carbon fuels such as green ammonia derived from green hydrogen, facilitated by the establishment of the Maersk Mc-Kinney Møller Center for Zero Carbon Shipping in 2020. While promising, these technologies are still in the early stages of development and require substantial investment in research and infrastructure.2
Digital solutions
Mobility-as-a-Service (MaaS) leverages digital platforms to provide users with multimodal trip planning, integrating modes like public transport, taxis, bikes, and car-sharing. It aims to shift users toward sustainable transport modes, as seen in Helsinki, where a significant modal shift from active modes to public transport was observed. However, its scalability and success depend on factors like business models, stakeholder involvement, and the quality of public transport infrastructure.
Moreover, leveraging data from various mobility modes, including apps like Strava, enhances urban planning precision, aiding in decarbonizing transport by optimizing vehicle distribution and minimizing congestion through informed planning and analysis.3
Current Challenges of Transport Decarbonization
Technological and financial barriers
The high costs of developing and deploying new technologies, such as green hydrogen production and advanced battery systems, present significant challenges. Ensuring the affordability and accessibility of these technologies is crucial for widespread adoption.4
Policy and regulatory frameworks
Inconsistent and unpredictable policy environments can hinder investment and progress in transport decarbonization. Clear, long-term strategies and stable regulatory frameworks are needed to provide certainty for investors and stakeholders.
Infrastructure development
The transition to zero-emission transport requires substantial investment in new infrastructure, including charging stations for EVs, refueling stations for hydrogen vehicles, and facilities for producing and distributing alternative fuels. Ensuring the resilience and adaptability of transport infrastructure to climate change impacts is also essential.3
Biofuel sustainability concerns
Shifting priorities and lack of policy predictability in the biofuel sector increase investment risks and diminish its attractiveness, compounded by uncertainties in advanced biofuel categorization. Overestimated greenhouse gas emission savings and biomass availability constraints have hindered biofuel deployment, necessitating policy support to address economic viability and reduce energy dependence through increased imports.1
Opportunities and Future Outlook
Global collaboration
International cooperation and dialogue are vital to sharing knowledge, best practices, and innovations in transport decarbonization. Initiatives like the Zero Emission Vehicles Transition Council and the Global Roadmap of Action toward Sustainable Mobility highlight the importance of collective action in accelerating the transition to sustainable transport.2
Shift toward public transport
Promoting public transport utilization through enhanced occupancy rates, adopting mobility-as-a-service platforms, and investing in infrastructure enhancements will reduce overall carbon emissions in transportation.5
Improve vehicle emissions
Implementing binding deadlines for transitioning away from fossil fuels and incentivizing the uptake of hybrid and optimized internal combustion engine vehicles, alongside increasing the market share of battery electric vehicles and plug-in hybrids, will accelerate decarbonization efforts in transportation.5
Equity and inclusivity
Ensuring that decarbonization efforts are inclusive and address the needs of underserved populations, including women and low-income communities, is essential. Equitable transport systems contribute to sustainability and enhance social and economic resilience.2
Decarbonizing the transport sector is imperative to mitigate the worst impacts of the climate crisis and achieve global climate goals. While significant challenges remain, integrating technological innovations, supportive policy frameworks, and collaborative efforts across sectors offers a pathway to a sustainable and resilient transport future. By leveraging the opportunities and addressing the challenges, the global community can accelerate the transition to zero-emission transport and contribute to a greener, more sustainable world.
References and Further Reading
- European Court of Auditors. (2023). Special report 29/2023: The EU's support for sustainable biofuels in transport – An unclear route ahead. Available at: https://www.eca.europa.eu/en/publications?ref=SR-2023-29
- UNCC. (2021). Transport - Climate Action Pathway. Available at: https://unfccc.int/climate-action/marrakech-partnership/reporting-tracking/pathways/transport-climate-action-pathway#Climate-Action-Pathway-2021
- Noussan, M., Hafner, M., & Tagliapietra, S. (2020). The future of transport between digitalization and decarbonization: Trends, strategies and effects on energy consumption (p. 112). Springer Nature. https://doi.org/10.1007/978-3-030-37966-7
- Searle, S., Bieker, G., & Baldino, C. (2021). Decarbonizing road transport by 2050: Zero-emission pathways for passenger vehicles. Available at: https://policycommons.net/artifacts/3803513/decarbonizing-road-transport-by-2050/4609341/
- EASAC. (2019). Decarbonization of transport: Options and Challenges. The European Academies' Science Advisory Council. Available at: https://easac.eu/fileadmin/PDF_s/reports_statements/Decarbonisation_of_Tansport
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