Climate Cooperation: The Role of Transport in Global GHG Reduction

The transport sector currently contributes approximately 23% of global energy-related CO2 emissions, making it one of the most challenging areas for climate mitigation. As countries work to meet the goals of the Paris Agreement, attention has increasingly turned to how electric vehicles and international collaboration can help reduce emissions from cars, trucks, ships, and planes. Decarbonising transport requires both technological innovation and unprecedented global cooperation, particularly as transport demand continues to grow in developing regions.

Understanding transport’s contribution to climate change 🔗

In 2019, direct greenhouse gas emissions from the transport sector reached 8.7 GtCO2-eq, up from 5.0 GtCO2-eq in 1990. Road vehicles account for the largest share of these emissions, with 70% of direct transport emissions coming from road transport, while 1%, 11%, and 12% came from rail, shipping, and aviation, respectively. This steady increase over three decades reflects both population growth and rising incomes, which drive greater demand for personal mobility and freight transport.

The growth in transport emissions has not been uniform across the globe. Transport-related emissions in developing regions of the world have increased more rapidly than in Europe or North America, a trend that is likely to continue in coming decades. This presents both a challenge and an opportunity. While rapid motorisation in Asia and Africa threatens to increase global emissions, these regions can potentially leapfrog to cleaner technologies if the right policies and international support are in place.

Electric vehicles as a climate solution 🔗

Battery electric vehicles have emerged as a cornerstone of transport decarbonisation strategies worldwide. The IPCC’s Sixth Assessment Report confirms that electromobility represents one of the most promising pathways for reducing emissions from land-based transport, particularly when vehicles are charged using low-carbon electricity.

Lifecycle emissions benefits of EVs 🔗

Today, there are already substantial emissions benefits to switching to EVs when emissions are considered on a lifecycle basis, which includes the emissions associated with the production of the vehicle as well as the well-to-wheel emissions. The IEA’s Global EV Outlook 2024 provides detailed analysis of these benefits across different scenarios and regions.

Globally, in the STEPS scenario, the lifecycle emissions of a medium-size battery electric car are about half of those of an equivalent internal combustion engine vehicle running on oil-based fuels, more than 40% lower than for an equivalent hybrid, and about 30% lower than for a plug-in hybrid over 15 years of operation. These advantages become even more pronounced as electricity grids continue to decarbonise.

BEVs are more energy efficient than ICEVs-they convert a greater share of energy into wheels and motion and require only about one-fourth or less of the energy needed to power a comparable conventional vehicle. This efficiency advantage means that even in regions with relatively carbon-intensive electricity grids, EVs typically outperform their petrol and diesel counterparts over their full lifecycle.

The role of plug-in hybrids 🔗

Plug-in hybrid electric vehicles serve as a transitional technology, offering flexibility for consumers who are not yet ready for fully electric vehicles. PHEVs purchased in 2023 produce around 30% less emissions than conventional vehicles over the course of their lifetime, while this gap reaches 35% for vehicles purchased in 2035 under the APS scenario, thanks to further decarbonisation of electricity generation.

However, the real-world performance of plug-in hybrids depends heavily on how they are used. Analysis from the past few years has shown that the real-world utility factor-the share of kilometres travelled on electricity-is significantly lower than the official values from vehicle type approvals. For PHEVs to deliver their full potential, drivers must regularly charge their vehicles and maximise electric driving.

Addressing manufacturing emissions 🔗

Because of the emissions from battery manufacturing, electric vehicles start their life with an emissions debt compared with conventional vehicles. Battery production, which accounts for approximately 25% of a BEV’s lifecycle emissions, involves mining and processing minerals such as lithium, nickel, and cobalt. However, this debt is typically offset within 1-2 years of driving and then the gap widens more and more in later years.

The IPCC notes that further efforts to reduce the GHG footprint of battery production are essential for maximising the mitigation potential of electric vehicles. Material and supply diversification strategies, energy and material efficiency improvements, and circular material flows can help reduce the environmental footprint of battery production over time.

Global collaboration is essential 🔗

Climate change fundamentally transcends national borders, and addressing transport emissions requires coordinated international action. Every sector of society-energy, industry, agriculture, transport and more-must act to reduce emissions and adapt to the climate impacts that are already affecting individuals and institutions alike. The transport sector presents unique challenges for international cooperation because it involves cross-border movement of goods and people, as well as internationally regulated sectors like aviation and shipping.

The Paris Agreement framework 🔗

The Paris Agreement, ratified in 2015, aims to limit global warming to well below 2°C above pre-industrial levels, with a target of 1.5°C. This agreement established the framework for Nationally Determined Contributions, through which countries outline their emissions reduction targets and plans. The transport sector is a significant contributor to global GHG emissions, accounting for 23% of energy-related CO2 emissions, and NDCs are the main tool for implementing the Paris Agreement.

The International Transport Forum highlights that while 98% of NDCs include some mention of transport, only 33% include specific emissions reduction targets for the sector. This gap between recognition and action represents a significant opportunity for improvement as countries submit their updated NDCs.

Transport targets in national climate plans 🔗

The Paris Agreement targets reducing global transport sector emissions from 7.7 gigatonnes per year down to 2-3 Gt by mid-century, instead of a business-as-usual scenario where emissions would increase to 13-15 Gt by 2050. Achieving this goal requires transformative changes across all transport modes and all regions.

The decarbonisation and transformation of the transport sector remains essential for achieving the Paris targets, as transport still accounts for 24% of global CO2 emissions from fuel combustion. International initiatives like the MobiliseYourCity Partnership support cities worldwide in transitioning to sustainable urban mobility, demonstrating how global cooperation can drive local action.

Progress and gaps in 2025 NDCs 🔗

The latest round of Nationally Determined Contributions, due in 2025, reveals both progress and persistent gaps. Only three G20 members include clear targets for zero-emissions vehicles in their NDCs. The UK has adopted a mandate requiring 80% of new cars to be zero-emissions by 2030, reaching 100% by 2035. Canada requires 100% zero-emissions vehicle sales by 2035, while the EU has set a target for all new cars and vans to be zero-emissions by 2035.

Belarus’s new NDC includes a focus on the transport sector with targets to increase the share of urban electric transport to 40% and expand the electric vehicle fleet to 693,000 units by 2035 under the most ambitious scenario. Such country-specific targets demonstrate how the Paris Agreement’s nationally determined approach can accommodate different national circumstances while driving progress.

Challenges in aviation and shipping 🔗

While electrification offers a clear path for decarbonising road transport, aviation and shipping present greater technological challenges. Aviation and shipping account for almost a quarter of transport-related CO2 emissions and show a dangerously sharp increase. These sectors cannot simply be electrified using current technology, requiring the development of alternative fuels and propulsion systems.

The IPCC assessment notes that advanced biofuels, ammonia, and synthetic fuels are emerging as viable options for these hard-to-electrify sectors. However, production facilities for these fuels require significant capital investment, and costs remain substantially higher than conventional fossil fuels. International agreements through bodies like the International Civil Aviation Organization and the International Maritime Organization have established emissions reduction targets, but progress towards adopting new technologies has been slow.

The deployment of low-carbon aviation and shipping fuels that support decarbonisation could require changes to national and international governance structures. Currently, the Paris Agreement does not specifically cover emissions from international shipping and aviation, leaving these sectors to be addressed through separate international mechanisms. Some researchers argue that including international transport under the Paris Agreement could strengthen decarbonisation efforts.

Urban design and systemic change 🔗

Beyond technology, reducing transport emissions requires fundamental changes to how cities and transport systems are designed. The IPCC estimates that cities can reduce their transport-related fuel consumption by around 25% through more compact land use and the provision of less car-dependent transport infrastructure. This includes creating walkable neighbourhoods, building protected cycling infrastructure, and investing in efficient public transit.

The report concludes that falling costs for renewable energy and for electric vehicle batteries, in addition to policy changes, have slowed the growth of climate change in the past decade, but that deep, immediate cuts are necessary to stop emissions growth entirely and keep global warming in check. This underscores that while progress is being made, the pace of change must accelerate significantly.

Behavioural changes also play a role. During the COVID-19 pandemic, the explosion of teleworking and video conferencing reduced travel, and, with it, emissions associated with commuting. While some of this reduction was temporary, the experience demonstrated that changes in work patterns and travel behaviour can meaningfully reduce transport emissions.

The path forward 🔗

Decarbonising transport requires action on multiple fronts simultaneously: accelerating the adoption of electric vehicles, developing clean fuels for aviation and shipping, redesigning cities to reduce car dependence, and strengthening international cooperation through improved climate commitments.

While current developments are expected to result in an increase of up to 50% in transport emissions, a maximum climate warming of 1.5°C requires a 60% reduction of transport-related emissions. Bridging this gap will require unprecedented coordination between governments, industry, and international organisations. The good news is that most zero-carbon alternatives in transport are cost competitive and mature enough for implementation.

The transition to cleaner transport also offers significant co-benefits beyond climate mitigation. Reduced air pollution improves public health, especially in urban areas. Investments in public transit and cycling infrastructure enhance mobility for people who cannot drive. And shifting to domestic clean energy sources can improve energy security and create local jobs.

What do you think? How can your community better integrate electric vehicles and public transit to reduce emissions? What role should international cooperation play in ensuring that developing countries can access clean transport technologies?

References

1. https://www.ipcc.ch/report/ar6/wg3/chapter/chapter-10/
2. https://www.iea.org/reports/global-ev-outlook-2024/outlook-for-emissions-reductions
3. https://www.itf-oecd.org/transport-ndc-guide
4. https://changing-transport.org/five-years-paris-agreement/