Global carbon transition in the passenger transportation sector over 2000–2021

The high-emitting and hard-to-abate passenger transport sector plays a crucial role in global deep decarbonization. To lead an equitable and rapid transition in the passenger transportation, this work is the first to develop a bottom-up modeling framework integrated with the latest decomposing structural decomposition methodology to assess and compare historical emission patterns and decarbonization efforts of 28 countries over the past two decades. Results indicate: (1) Carbon emissions from the global passenger transport sector increased between 2000 and 2021, peaking in 2019, with GDP per capita and population size being key drivers of rising carbon emissions across countries. (2) The decarbonization efforts of the global passenger transport sector varied by traffic mode. The largest contributors were passenger buses [−0.46 megatons of carbon dioxide per year (Mt CO₂/yr)], followed by trains (−0.4 Mt CO₂/yr), and airplanes (−0.28 Mt CO₂/yr), while passenger cars (1.04 Mt CO₂/yr) hindered the decarbonization process. (3) Although the global passenger transport sector has cumulatively decarbonized 3005.9 Mt CO₂ and achieved a decarbonization rate of 5.1 %, regional performance varied significantly, exhibiting uneven and inadequate progress. Overall, the study provides an effective data-driven assessment framework for reviewing and comparing global and national passenger transport decarbonization performance, which will facilitate the planning of decarbonization pathways by global emitters and the early achievement of zero-carbon transport.