Researchers in Japan have simulated how to achieve a deep reduction in transport-related emissions by 2100 to help meet climate targets.

“The policy with the highest priority is to strongly promote fully battery electric-powered vehicles to achieve the goal of deep decarbonization in the transport sector,” says Runsen Zhang of Hiroshima University. “In addition, social transformations such as lifestyle change and low-carbon urban reorganization could be effective.”

Currently, around a quarter of global carbon dioxide emissions are from transportation. Future savings will need to take place alongside a predicted growth in the demand for transport driven by increased car use and buoyed by a rise in domestic shipping.

“The stronger the mitigation intensity, the more transport-specific policy is required,” says Zhang, who worked with colleagues at the National Institute for Environmental Studies in Tsukuba and Kyoto University.

The group considered the interaction between transport policies, global dynamics of transport demand, mitigation potential, and the cost of meeting goals to limit warming to below 2 °C and 1.5 °C.

The researchers looked at energy efficiency improvements and innovations in vehicle technology — particularly in the deployment of electric vehicles — as well as developments in public transport and increasing the car occupancy rate. They coupled detailed transport models with the integrated assessment models used to guide environmental policy. The work provides more information on the interplay between mitigation options and the dynamics of the macroeconomy, including trends in GDP.

The study assumed that the cost of electric vehicles continues to decline over the coming decades, and the researchers note that liquid fuel savings can be realized directly by the deployment of hybrid vehicles. Such designs are predicted to become a significant fraction of new vehicle sales in the interim before road transportation becomes fully electric.

The simulations reveal that technological policy interventions have the potential to make a significant impact on emissions. However, fossil fuel use could be difficult to eliminate entirely — at least until solutions can be found for electrified shipping and aviation — which points to the need for negative emissions to balance this.

The team published their findings in Environmental Research Letters ( ERL ) .