From Electric Vehicles to Carpooling: How Global Warming Could Slow Due to Changes in Transportation

All over the world, revolutionary changes are underway in transportation. More and more electric vehicles are on the road, people are taking advantage of shared mobility services such as Uber and Lyft, and the increase in working from home during the COVID-19 pandemic has changed the way people think about commuting.

Transport is a growing source of global greenhouse gas emissions that drive climate change, accounting for 23% of energy-related carbon dioxide emissions globally in 2019 and 29% of all emissions greenhouse gases in the United States. Ongoing systemic changes in the transport sector could begin to reduce this carbon footprint. But will they reduce emissions enough?

In a new report from the Intergovernmental Panel on Climate Change released April 4, 2022, scientists reviewed the latest research on efforts to mitigate climate change. The report concludes that falling costs of renewables and electric vehicle batteries, in addition to policy changes, have slowed the growth of climate change over the past decade, but that deep and immediate cuts are needed. Emissions will need to peak by 2025 to keep global warming to 2.7 degrees Fahrenheit, a goal of the Paris climate accord, the report said.

The transport chapter, to which I contributed, focused on transport transformations – some just beginning and others expanding – which, in the most aggressive scenarios, could reduce global gas emissions to greenhouse effect from transport to 80% to 90% of current levels by 2050. This kind of drastic reduction would require a major and rapid overhaul of the way people move around the world.

The future of EVs

All-electric vehicles have grown dramatically since the Tesla Roadster and Nissan Leaf hit the market just over a decade ago, following the popularity of hybrids. In 2021 alone, sales of electric passenger vehicles, including plug-in hybrids, doubled globally to 6.6 million, or around 9% of all car sales that year.

Strong regulatory policies have encouraged electric vehicle production, including California’s zero-emission vehicle regulations, which require automakers to produce a certain number of zero-emission vehicles based on the total number of vehicles sold in California; European Union CO2 emission standards for new vehicles; and China’s policy on new energy vehicles, all of which have helped push EV adoption to where we are today.

Beyond passenger vehicles, many micro-mobility options – such as rickshaws, scooters and bicycles – as well as buses have been electrified. As the cost of lithium-ion batteries declines, these transportation options will become increasingly affordable and further drive sales of battery-powered vehicles that have traditionally run on fossil fuels.

An important aspect to remember about the electrification of the transport system is that its ability to reduce greenhouse gas emissions ultimately depends on the cleanliness of the electricity grid. China, for example, aims to have 20% of its vehicles electric by 2025, but its power grid is still heavily dependent on coal.

With global trends towards more renewable production, these vehicles will be connected with less carbon emissions over time. There are also many developing and potentially promising co-benefits of electromobility when coupled to the electrical system. Electric vehicle batteries have the potential to act as storage devices for the grid, which can help stabilize the intermittency of renewable resources in the power sector, among many other benefits.

Other areas of transportation are more difficult to electrify. Larger and heavier vehicles are generally not as conducive to electrification as the size and weight of the batteries required quickly become unsustainable.

For some heavy goods vehicles, ships and aircraft, alternative fuels such as hydrogen, advanced biofuels and synthetic fuels are being explored to replace fossil fuels. Most are not yet economically feasible, and substantial technological advancements are still needed to ensure they are low- or zero-carbon.

Other Ways to Reduce Transportation Emissions

While new fuel and vehicle technologies are often touted as decarbonizing solutions, behavioral and other systemic changes will also be required to significantly reduce greenhouse gas emissions from this sector. We are already in the midst of these changes.

Telework : During the COVID-19 pandemic, the explosion of telecommuting and videoconferencing has reduced travel and with it the emissions associated with travel. Although some of this figure is rebounding, teleworking is expected to continue in many sectors of the economy.

Shared mobility: Some shared mobility options, like bike and scooter sharing programs, can get more people out of vehicles altogether.

Car-sharing and on-demand services such as Uber and Lyft also have the potential to reduce emissions if they use high-efficiency or zero-emission vehicles, or if their services lean more towards carpooling, with each driver taking several passengers. Unfortunately, there is great uncertainty about the impact of these services. They could also increase vehicle use and, with it, greenhouse gas emissions.

New policies like the California Clean Miles Standard are helping push companies like Uber and Lyft to use cleaner vehicles and increase their ridership, but it remains to be seen whether other regions will adopt similar policies.

Transit-friendly cities: Another systemic change concerns urban planning and design. Transport in urban areas is responsible for about 8% of global carbon dioxide emissions.

Efficient urban planning and land use can reduce travel demand and shift transportation modes from cars to public transit through strategies that avoid sprawl and discourage personal cars. Not only do these improvements reduce greenhouse gas emissions, but they can reduce congestion, air pollution and noise, while improving the safety of transportation systems.

How does this progress translate into reduced emissions?

Much of the uncertainty about the impact of technological change and other systemic changes in transportation on global warming is related to the rate of transition.

The new IPCC report includes several potential scenarios to determine how much transportation improvements can reduce emissions. On average, the scenarios indicate that the carbon intensity of the transport sector is expected to decrease by around 50% by 2050 and up to 91% by 2100 when combined with a cleaner electricity grid to remain in the 1.5 degree Celsius (2.7 F) target range for global warming.

These decreases would require a complete reversal of current trends of increasing emissions in the transportation sector, but recent advances in transportation offer many opportunities to address this challenge.

Teresa H. Sadler