Introduction

The world is facing a climate crisis due to the increasing concentration of greenhouse gases (GHGs) in the atmosphere, primarily carbon dioxide (CO2) from human activities such as burning fossil fuels. The transportation sector is a significant contributor to global carbon emissions, accounting for approximately 23% of total energy-related CO2 emissions and 14% of all GHG emissions. Within the transportation sector, the urban and suburban passenger land transport sector is a major contributor to carbon emissions, accounting for about 40% of total transportation emissions. Therefore, decarbonisation of this sector is crucial to achieving the global goal of limiting the temperature rise to 1.5°C above pre-industrial levels, as outlined in the Paris Agreement. This article discusses the concept of decarbonisation, the main sources of carbon emissions, ways to reduce carbon emissions, challenges facing decarbonisation, and implications for the urban and suburban passenger land transport sector.

What is Decarbonisation in Urban and Suburban Passenger Land Transport?

Decarbonisation refers to the reduction of carbon emissions from human activities, such as transportation, to mitigate the negative impacts of climate change. In the context of urban and suburban passenger land transport, decarbonisation involves reducing the carbon emissions from vehicles, infrastructure, and operations. This can be achieved through the use of low-carbon fuels, such as electricity, hydrogen, and biofuels, as well as the adoption of more efficient and sustainable transportation modes, such as public transport, cycling, and walking.

Why is Decarbonisation Important?

Decarbonisation of the urban and suburban passenger land transport sector is essential for several reasons. Firstly, it contributes to the global effort to limit the temperature rise to 1.5°C above pre-industrial levels and avoid the worst impacts of climate change, such as sea-level rise, extreme weather events, and biodiversity loss. Secondly, it improves air quality, which is a significant public health concern, particularly in urban areas where air pollution is a leading cause of premature deaths. Thirdly, it reduces the dependence on fossil fuels, which are finite resources and subject to price volatility and geopolitical tensions. Fourthly, it enhances energy security by diversifying the energy mix and reducing the reliance on imported oil. Lastly, it promotes sustainable and inclusive urban development by providing affordable, accessible, and safe transportation options for all, regardless of income, gender, age, or ability.

What are the Main Sources of Carbon Emissions in Urban and Suburban Passenger Land Transport?

The main sources of carbon emissions in urban and suburban passenger land transport are vehicles, infrastructure, and operations. Vehicles are the largest source of emissions, accounting for about 80% of total emissions. The emissions from vehicles are primarily from the combustion of fossil fuels, such as gasoline and diesel, which produce CO2, as well as other pollutants, such as nitrogen oxides (NOx), particulate matter (PM), and volatile organic compounds (VOCs). The emissions from vehicles depend on several factors, such as fuel efficiency, vehicle size and weight, driving behavior, and traffic conditions. Infrastructure, such as roads, bridges, tunnels, and parking facilities, also contributes to emissions, mainly from the embodied energy and emissions from construction materials and maintenance activities. Operations, such as traffic management, logistics, and maintenance, also generate emissions, mainly from energy consumption and waste generation.

How Can We Reduce Carbon Emissions in Urban and Suburban Passenger Land Transport?

Reducing carbon emissions in urban and suburban passenger land transport requires a comprehensive and integrated approach that addresses the sources of emissions and promotes sustainable and efficient transportation modes. Some of the ways to reduce carbon emissions are:

1. Electrification: The use of electric vehicles, powered by renewable electricity, can significantly reduce carbon emissions from vehicles. Electric vehicles have zero tailpipe emissions and are more energy-efficient than internal combustion engine vehicles. However, the deployment of electric vehicles requires the development of charging infrastructure, the adoption of supportive policies, such as incentives and regulations, and the integration with renewable energy systems.
2. Public Transport: The promotion of public transport, such as buses, trains, and trams, can reduce carbon emissions by replacing private cars and reducing congestion. Public transport is more energy-efficient than private cars and can accommodate more passengers per vehicle. However, the provision of public transport requires investment in infrastructure, vehicles, and operations, as well as the integration with other modes of transport, such as cycling and walking.
3. Active Transport: The promotion of active transport, such as cycling and walking, can reduce carbon emissions by replacing motorized transport and promoting physical activity. Active transport is emission-free and has several health benefits, such as reducing the risk of obesity, diabetes, and cardiovascular diseases. However, the provision of active transport requires investment in infrastructure, such as cycle lanes and pedestrian paths, and the promotion of safety and accessibility.
4. Low-Carbon Fuels: The use of low-carbon fuels, such as hydrogen and biofuels, can reduce carbon emissions from vehicles. Hydrogen fuel cells produce water as the only emission and can be powered by renewable electricity. Biofuels can be produced from renewable sources, such as waste biomass, and can replace fossil fuels in existing vehicles. However, the deployment of low-carbon fuels requires the development of supply chains, the adoption of supportive policies, such as mandates and incentives, and the consideration of environmental and social impacts.
5. Efficient Operations: The promotion of efficient operations, such as eco-driving, logistics optimization, and maintenance management, can reduce carbon emissions from vehicles and infrastructure. Efficient operations can improve fuel efficiency, reduce idle time, and minimize waste generation. However, the implementation of efficient operations requires the adoption of best practices, the training of personnel, and the monitoring of performance.

What are the Challenges Facing Decarbonisation in Urban and Suburban Passenger Land Transport?

Decarbonisation of the urban and suburban passenger land transport sector faces several challenges that need to be addressed to achieve the desired outcomes. Some of the challenges are:

1. Cost: The transition to low-carbon modes of transport and fuels requires significant investment in infrastructure, vehicles, and operations. The cost of this investment can be a barrier, particularly for developing countries and low-income populations. The cost of low-carbon technologies, such as electric vehicles and hydrogen fuel cells, is also higher than conventional vehicles and fuels, although it is expected to decrease over time.
2. Infrastructure: The deployment of low-carbon modes of transport and fuels requires the development of infrastructure, such as charging stations, hydrogen refueling stations, and cycle lanes. The availability and accessibility of this infrastructure can be a challenge, particularly in rural and remote areas, where the demand for low-carbon transport is lower. The integration of different modes of transport, such as public transport and active transport, also requires infrastructure that promotes safety and convenience.
3. Policy: The adoption of supportive policies, such as incentives, regulations, and standards, is essential to promote the transition to low-carbon transport. However, the design and implementation of these policies can be challenging, particularly in the absence of political will, stakeholder engagement, and public awareness. The coordination and coherence of policies across different levels of government, such as national, regional, and local, are also critical to avoid conflicting objectives and priorities.
4. Behavior: The adoption of low-carbon modes of transport and fuels requires changes in behavior, such as the willingness to use public transport, cycle, or walk, and the acceptance of new technologies, such as electric vehicles and hydrogen fuel cells. The behavior change can be challenging, particularly in the absence of incentives, awareness, and social norms that promote sustainable and efficient transport. The cultural and social factors that influence behavior, such as gender, age, income, and education, also need to be considered.

What are the Implications of Decarbonisation for Urban and Suburban Passenger Land Transport?

Decarbonisation of the urban and suburban passenger land transport sector has several implications that need to be considered to achieve the desired outcomes. Some of the implications are:

1. Equity: The transition to low-carbon modes of transport and fuels should promote equity and social inclusion, particularly for disadvantaged populations, such as low-income households, women, children, and persons with disabilities. The provision of affordable, accessible, and safe transport options for all is critical to avoid the exclusion of certain groups from the benefits of decarbonisation.
2. Innovation: The transition to low-carbon modes of transport and fuels requires innovation and technological development, particularly in the areas of electric vehicles, hydrogen fuel cells, and biofuels. The promotion of research and development, as well as the collaboration between academia, industry, and government, is critical to accelerate the deployment of innovative solutions.
3. Collaboration: The transition to low-carbon modes of transport and fuels requires collaboration and partnership between different stakeholders, such as government, industry, civil society, and academia. The coordination and coherence of actions across different sectors, such as energy, environment, and transport, are critical to avoid unintended consequences and optimize the benefits of decarbonisation.
4. Monitoring: The transition to low-carbon modes of transport and fuels requires monitoring and evaluation of the performance and impacts of different solutions. The collection and analysis of data, as well as the dissemination of information, are critical to inform decision-making, improve accountability, and promote learning.

Conclusion

Decarbonisation of the urban and suburban passenger land transport sector is essential to achieve the global goal of limiting the temperature rise to 1.5°C above pre-industrial levels and avoid the worst impacts of climate change. The reduction of carbon emissions requires a comprehensive and integrated approach that addresses the sources of emissions and promotes sustainable and efficient transportation modes. The challenges facing decarbonisation, such as cost, infrastructure, policy, and behavior, need to be addressed to achieve the desired outcomes. The implications of decarbonisation, such as equity, innovation, collaboration, and monitoring, need to be considered to optimize the benefits of decarbonisation. The transition to low-carbon modes of transport and fuels is a complex and long-term process that requires the commitment and cooperation of different stakeholders.