Transport is a significant contributor to global carbon dioxide (CO2) emissions, accounting for approximately one-fifth of the total worldwide emissions. When focusing solely on CO2 emissions derived from energy consumption, this sector represents almost a quarter of the global share. Within the transport sector, cars, along with other road vehicles, play a dominant role in this emission landscape.
To understand the breakdown of these emissions, it’s crucial to examine the contributions of different transport modes. Data from 2018, compiled by the International Energy Agency (IEA), provides a clear picture of where transport emissions originate.
Road travel is responsible for the lion’s share of transport emissions, constituting three-quarters of the total. Passenger vehicles, primarily cars and buses, are the biggest contributors within road transport, accounting for 45.1% of the sector’s emissions. Freight transport by trucks contributes a further 29.4%.
Considering that the entire transport sector generates 21% of all global CO2 emissions, and road transport makes up three-fourths of this, it’s evident that road transport, heavily influenced by Cars Transport, is responsible for roughly 15% of total global CO2 emissions.
While aviation often receives considerable attention in climate change discussions, it only accounts for 11.6% of transport emissions. This equates to just under one billion tonnes of CO2 annually, approximately 2.5% of global emissions. International shipping produces a comparable amount of emissions, at 10.6%.
Rail transport and freight contribute minimally, representing only 1% of transport emissions. Other forms of transport, mainly involving the movement of materials like water, oil, and gas through pipelines, account for 2.2%.
The Future of Cars Transport: Moving Towards Zero-Carbon
As the world’s population grows and economies develop, the demand for transport is projected to increase significantly in the coming decades. Rising incomes will enable more people to afford personal vehicles, including cars, as well as utilize trains and air travel. The IEA’s “Energy Technology Perspectives” report anticipates a doubling of global transport activity (measured in passenger kilometers), a 60% rise in car ownership rates, and a tripling of demand for both passenger and freight aviation by 2070. These trends, if unchecked, would lead to a substantial surge in transport-related emissions.
However, technological advancements offer a pathway to mitigate this increase. The transition towards cleaner electricity sources, coupled with the rise of electric vehicles (EVs), presents a viable strategy to reduce emissions from passenger cars and buses. Electric cars transport is becoming increasingly important in the global decarbonization effort.
The IEA’s “Sustainable Development Scenario,” aiming for net-zero CO2 emissions from the energy sector by 2070, reflects this potential. This scenario envisions a phase-out of emissions from motorcycles by 2040, rail by 2050, and smaller trucks by 2060. While complete elimination of emissions from cars and buses is projected by 2070, many regions, including the European Union, the United States, China, and Japan, are expected to phase out conventional combustion engine vehicles as early as 2040. This transition highlights the critical role of electric cars transport in achieving these goals.
Decarbonizing other transport sub-sectors presents greater challenges. Research published in Science by Steven Davis and colleagues identifies long-distance road freight (large trucks), aviation, and shipping as particularly difficult to decarbonize. The limitations of current battery and hydrogen technology in terms of range and power for these sectors mean that alternatives to combustion engines are not straightforward replacements. The size and weight of batteries or hydrogen fuel tanks required for planes, ships, and large trucks would far exceed those of traditional engines.
Despite significant reductions projected in the IEA’s scenario, these hard-to-decarbonize sectors could still make transport the largest emitter in the energy sector by 2070. Achieving net-zero emissions for the entire energy sector will necessitate offsetting these remaining emissions through “negative emissions” technologies, such as carbon capture and storage from bioenergy or direct air capture technologies.
The IEA emphasizes that nearly two-thirds of the emission reductions in their net-zero scenario depend on technologies that are not yet commercially widespread. Reducing CO2 emissions from cars transport and the broader transport sector in the coming decades is indeed a significant challenge.
Global CO2 emissions from transport in the IEA’s Sustainable Development Scenario to 2070
Projected CO2 emissions from transport sectors to 2070, highlighting the reduction pathway for cars, buses, trucks, aviation, and shipping under the IEA's Sustainable Development Scenario.
References
International Energy Agency (IEA). Energy Technology Perspectives. 2020.
Davis, Steven J., et al. “Net-zero emissions energy systems.” Science, vol. 366, no. 6464, 2019, pp. 447-454.
