Vision 2050: Strategies to align global road transport with well below 2°C

This work builds on the modeling in Sen and Miller (2023), and the ICCT teamed with several key partners to leverage their expertise and explore the potential of a variety of additional strategies to decarbonize global road transport. The strategies assessed in this analysis are: further accelerating the transition of new vehicle sales to zero-emission vehicles (ZEVs); accelerating the transition of used vehicle imports to ZEVs; further deployment of internal combustion engine (ICE) efficiency technology for new light-duty vehicles; further deployment of ICE efficiency technology for new heavy-duty vehicles; passenger vehicle avoid-and-shift measures in urban areas; freight vehicle avoid-and-shift measures and operational efficiency improvements; and fleet renewal strategies to shift vehicle activity from older ICE vehicles to new vehicles.

Sen and Miller (2023) demonstrated that a scenario of Ambitious ZEV Sales encompassing a full phaseout of sales of new non-ZEV vehicles globally by 2045 can ensure that the road transport emissions trajectory is compatible with a 67% likelihood of achievement of a below-2°C pathway without overshoot. This study shows that a combination of additional strategies in the “All Out” scenario could further reduce emissions in line with a well-below 2°C pathway with the same parameters. This is similar to what a previous ICCT study, Graver et al., (2022, found is achievable for the aviation sector, but is still far from a pathway that aligns with 1.5°C. The sizeable work that remains is underscored by another finding of this study, that projected CO2 emissions from vehicles that are already on the road today would exceed the limited carbon budget remaining to avoid overshoot of 1.5°C. Indeed, the cumulative emissions from selling no new vehicles going forward are only 10 billion tonnes lower than the All Out scenario when no other measures are implemented.

Ending all car sales tomorrow is not a feasible option, but the strategies identified in this paper are, and are nearly as effective. In particular, Ambitious ZEV Sales for new vehicles combined with restricting the age of used vehicle sales to no more than 5 years for light-duty vehicles and no more than 8 years for heavy-duty vehicles (both with a three-year dispensation for Africa) could avoid an additional 61 billion tonnes of cumulative CO2 emissions globally; this contributes 42% of the emission reductions in the All Out scenario, more than any other two strategies combined. But it also highlights the scale of the challenge in reducing emissions from new and used vehicles in time to avoid overshoot of 1.5°C. While some additional strategies could be considered in future studies, carbon removal technologies may also need to play a role if in-sector efforts are not able to bridge this gap.

Additional Materials:
Expanded Methodology: Data and methods of analysis used in developing strategies to align global road transport with well below 2°c