What is United States's pathway to limit global warming to 1.5°C?
Transport
Decarbonising the transport sector
In 2021, transport was the highest source of emissions in the US, just ahead of the power sector.1 However, while power sector emissions have continued to fall over the last two decades, transport emissions have remained stable.2 Oil has persisted as the dominant fuel used in transport, accounting for 89% of the transport fuel mix in 2021.3 Remaining demand is met largely by fossil gas and biofuel. The share of electricity remains negligible; however, EVs have seen considerable market growth in recent years.4
United States' energy mix in the transport sector
petajoule per year
Fuel shares refer only to energy demand of the sector. Deployment of synthetic fuels is not represented in these pathways.
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Graph description
Energy mix composition in the transport sector in consumption (EJ) and shares (%) for the years 2030, 2040 and 2050 based on selected IPCC AR6 global least costs pathways.
Methodology
Data References
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In the Deep Electrification pathway (which best captures the potential for rapid electrification driven by cost reductions in wind and solar) the share of electricity in the transport energy mix increases from less than 1% in 2021 to 11% by 2030 and 60% by mid-century.
In 2021, President Biden announced a target for zero-emissions vehicles to reach 50% of all new vehicles sold by 2030.5 However, even this large targeted ramp-up in EV sales is not compatible with the Paris Agreement according to analysis by the Climate Action Tracker, which shows 95–100% of sales of new light duty vehicles in the US should be zero-emissions by 2030.6 The 2022 Inflation Reduction Act and other legislation has targeted expansion of EV adoption, manufacturing and charging infrastructure.7,8
Across all 1.5°C aligned pathways, energy demand in the transport sector declines by 49–60% below 2021 levels by 2050. This indicates modal shifts from road to rail in both passenger and freight transport and efficiency gains from electrification are key to driving down transport emissions.
While dedicated investment in high-speed rail was cut from the Inflation Reduction Act, the Bipartisan Infrastructure Law includes USD 66 billion for rail.9 In December 2023, the Biden Administration announced USD 8.2 billion of this funding for major passenger rail projects including new high-speed rail lines.10
United States' transport sector direct CO₂ emissions (from energy demand)
MtCO₂/yr
Direct CO₂ emissions only are considered (see power sector for electricity related emissions, hydrogen and heat emissions are not considered here).
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Graph description
Direct CO₂ emissions of the transport sector in selected 1.5°C compatible pathways.
Methodology
Data References
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1.5°C compatible transport sector benchmarks
Direct CO₂ emissions and shares of electricity, biofuels and hydrogen in the transport final energy demand from illustrative 1.5°C pathways for United States
| Indicator |
2021
|
2030
|
2035
|
2040
|
2050
|
Decarbonised transport sector by
|
|---|---|---|---|---|---|---|
|
Direct CO₂ emissions
MtCO₂/yr
|
1664
|
1146 to
1216
|
631 to
987
|
291 to
642
|
133 to
211
|
2065
|
|
Relative to reference year in %
|
-31 to
-27%
|
-62 to
-41%
|
-83 to
-61%
|
-92 to
-87%
|
| Indicator |
2021
|
2030
|
2035
|
2040
|
2050
|
|---|---|---|---|---|---|
|
Share of electricity
per cent
|
0
|
3 to
11
|
8 to
30
|
16 to
48
|
33 to
60
|
|
Share of biofuels
per cent
|
6
|
5 to
10
|
7 to
15
|
8 to
23
|
20 to
37
|
|
Share of hydrogen
per cent
|
0
|
0 to
1
|
1 to
2
|
1 to
4
|
1 to
7
|
All values are rounded. Direct CO₂ emissions only are considered (see power sector analysis, hydrogen and heat emissions are not considered here). Year of full decarbonisation is based on carbon intenstiy threshold of 5gCO₂/MJ.
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Methodology
Data References
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