In Figure 1, we plot the evolution of global greenhouse gas emission esti-mates from these subsectors from 1970 to 2018, based on European Commission(2023). For comparison, worldwide greenhouse gas emissions across all sectorsof the economy were roughly 36 gigatons in 2018 (IEA 2022b). Figure 1 suggeststwo themes that will recur throughout the essay: the centrality of road vehicles inthe task of decarbonizing transportation and the ongoing rise in transportationFigure 1Transportation Emissions by SectorSource: Emissions Database for Global Atmospheric Research (European Commission 2023).Note: This figure plots annual emissions greenhouse gas emissions (in gigatons) for five transportationsectors from 1970 to 2018.01234Greenhouse gas emissions (gigatons)1970 1980 1990 2000 2010 2020OECD – roadNon OECD – roadAviationWater-borneRail /other
ongoing rise in transporation emissions in developing countries.