Data Source: California Air Resources Board, California Greenhouse Gas Inventory - by Sector
Analysis by CEC Economics
Highlights
- In 2022, GHG emissions across all sub-sectors within the transportation sector were 13.5% (-22.3 MMTCO2e) lower compared to 2019 emissions. This indicates that the rebound from 2020 to 2021 was temporary as the state continues to decarbonize its transportation sector even as travel has increased since the pandemic. Within the transportation sector, on-road vehicles emissions, which make up 90% of transportation’s emissions, were 14.1% (-21.3 MMTCO2e) lower in 2022 than 2019. Within the on-road vehicles sub-sector, emissions from passenger vehicles had the largest decline of 11.9% (-13.7 MMTCO2e) from 2019 levels, followed by the heavy-duty vehicles sub-sector which declined by 22.1% (-7.8 MMTCO2e). Emissions from other transportation subsectors (aviation, rail, ships sub-sector, other and not specified) fell by 5.5% (-0.9 MMTCO2e), compared to 2019.
- As a share of total emissions, the transportation sector was 38.7% in 2022, up by 0.9% compared to 2020 but lower than in the 2016 to 2019 period when it hovered over 40%. The sector’s GHG emissions totaled 143.6 MMTCO2e in 2022, down 3.6% (-5.4 MMTCO2e) from 2021. Within the transportation sector, on-road vehicles GHG emissions decreased by 4.2% (-5.7 MMTCO2e) from 2021. The majority of the year-over-year decrease in transportation sector emissions can be attributed to the heavy-duty vehicles sector, which fell by 13.1% (-4.1 MMTCO2e) from 2021. However, emissions from the aviation sub-sector grew by 21.7% (+0.7 MMTCO2e) from 2021 due to the continued easing of travel restrictions since the peak of the pandemic in 2020.
- Distillate (diesel) fuel combustion from heavy-duty trucks accounted for the lion’s share of reduction in heavy-duty vehicle subsector’s emissions, falling 17.5% (-4.0 MMTCO2e) in 2022 from 2021. This reduction could be attributed to various factors such as improved technologies, more efficient fuel usage, or regulations aimed at reducing emissions from heavy-duty diesel vehicles. The California Air Resources Board (CARB) is actively addressing heavy-duty vehicle pollution to reduce smog-forming oxides of nitrogen (NOx) and toxic diesel particulate matter (PM) emissions. CARB aims to meet California's air quality standards and greenhouse gas emissions reduction goals, with a focus on achieving 100% zero-emission transportation by 2035 for off-road transport refrigeration units (TRUs) and drayage vehicles, and 2045 for all other heavy-duty vehicles.14
14The California Air Resources Board (CARB). New California requirements for heavy-duty vehicles and TRUs. Available at: https://ww2.arb.ca.gov/new-california-requirements-heavy-duty-vehicles-and-trus
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