What is United States's pathway to limit global warming to 1.5°C?

Future Pathway

Current trends and future pathways

As the Trump administration continues to take aggressive action to roll back climate and environmental policy across sectors, the near-term emissions pathway for the United States is highly uncertain. While emissions are expected to continue to decrease, as states and markets continue to move towards renewable electrification, a “substantial deceleration in emission reductions” is projected when considering the impact of Trump’s major legislative package – the One Big Beautiful Bill Act (OBBB) – and the repeal of emissions standards in the power and transport sectors.1,2

Emissions excluding LULUCF are projected to drop 14-18% below 2010 levels by 2030, and 19-24% by 2035. Emissions under the Trump administration are projected to be roughly 15% higher in 2030 and 13-18% higher in 2035 than previous policy projections, which included the Inflation Reduction Act and other major Biden-era policies.

Under the Trump administration, the United States has exited the Paris Agreement, voiding the 2030 and 2035 NDC targets.3 For further evaluation of the United States’ policies and previous targets, see the Climate Action Tracker.4

In the Highest Possible Ambition (HPA) scenario, the United States would need to reduce emissions 71% below 2005 levels in 2035, to 2181 MtCO₂e (excluding LULUCF). Emissions in 2040 would need to fall 91% below 2010 levels excluding LULUCF, dropping and plateauing at roughly 102% below 2010 levels (excluding LULUCF) from 2050. A rapid phase out of fossil fuels driven by electrification and integration of renewables and clean technologies will be fundamental to aligning with this scenario.

United States' total GHG emissions MtCO₂e/yr

Displayed values

Reference Year

Target Year

*This pathway reflects the level of mitigation ambition needed domestically to align the country with a cost-effective breakdown of the global emissions reductions in the HPA scenario. For developing countries, achieving these reductions will require international support.  

  • Graph description

    The figure shows a national 1.5°C compatible emissions pathway for total GHG emissions excl. LULUCF in the Highest Possible Ambition scenario. Emissions data is presented in global warming potential (GWP) values from the IPCC's Fifth Assessment Report (AR5). While we don’t present country-level estimates, the HPA scenario rapidly scales CDR from the 2030s onwards, with engineered removals reaching around 5 GtCO2/yr by 2050, supported by limited removals of around 2 GtCO2/yr from the land-use system. The HPA scenario avoids large-scale nature-based CDR, given the risks of overreliance on natural sinks in a warming world. 

    Methodology

    Data References

Long term pathway

The HPA scenario requires significant emissions cuts globally between now and 2040 to achieve net zero CO₂ before 2040 and reach net zero GHG emissions in the 2060s, minimising overshoot of the 1.5ºC limit. While we currently do not specify country-level CDR results, we find that it is a key lever at the global scale. The HPA scenario rapidly scales CDR deployment from the 2030s onwards, which is critical to achieving net-negative CO₂ emissions and compensating for remaining residual emissions (typically from agriculture, waste, and industrial processes). Further details on our global approach to CDR, including sustainability and feasibility bounds and the role of the land sector can be found in the methodology and our report Rescuing 1.5ºC: new evidence on the highest possible ambition to deliver the Paris Agreement.5

The HPA scenario also shows the need to reach net-negative GHG emissions to bring temperatures back down well below 1.5ºC as fast as possible. In the HPA, global net-negative emissions are sustained over 2060–2100, but in some countries this regime of net-negative emissions appears earlier. In the United States currently, emissions excluding LULUCF reach net zero shortly before 2050 and then become net-negative.

The exact distribution of a future net-negative emissions regime, both in terms of where CDR is deployed to achieve net-negative emissions, and how this CDR is financed, is an active area of research. We are conducting further research on this presently. Our current results for this net-negative regime should be seen as preliminary and subject to further revision.

Rather than focusing on this regime, we highlight the need for the United States to reach net zero CO₂ shortly before 2040 and net zero GHGs shortly before 2050. What happens after reaching net zero will be a function of global and national policy responses, international collaboration on CDR and technological progress in scaling removals and will be investigated further in future stages of the project.

United States' total CO₂ emissions excl. LULUCF MtCO₂/yr

1.5°C compatible emissions benchmarks

Key emissions benchmarks for United States. Benchmarks are based on the HPA scenario. Relative reductions are provided based on the reference year.

Reference Year

LULUCF

Indicator
2015
Reference year
2023
2030
2035
2040
2050
2060
2070
Total GHG
Megatonnes CO₂ equivalent per year
6736
6192
4120
2181
666
-159
-233
-339
Relative to reference year in %
-39%
-68%
-90%
-102%
-103%
-105%
Total CO₂
MtCO₂/yr
5070
4630
2877
1171
-177
-734
-779
-845
Relative to reference year in %
-43%
-77%
-103%
-114%
-115%
-117%
Total GHG
Megatonnes CO₂ equivalent per year
5916
1513 to 2191
703 to 1201
-55 to 614
-517 to 33
-517 to 148
-805 to 63
Relative to reference year in %
-74 to -63%
-88 to -80%
-101 to -90%
-109 to -99%
-109 to -97%
-114 to -99%
Total CO₂
MtCO₂/yr
4250
-2607 to -1929
-1479 to -981
-722 to -52
-359 to 191
-284 to 381
-465 to 402
Relative to reference year in %
-161 to -145%
-135 to -123%
-117 to -101%
-108 to -96%
-107 to -91%
-111 to -91%

All information excluding LULUCF emissions and novel CDR approaches. While we don’t present country-level estimates, the HPA scenario rapidly scales CDR from the 2030s onwards, with engineered removals reaching around 5 GtCO2/yr by 2050, supported by limited removals of around 2 GtCO2/yr from the land-use system. The HPA scenario avoids large-scale nature-based CDR, given the risks of overreliance on natural sinks in a warming world. 
All values are rounded. Emissions data is presented in global warming potential (GWP) values from the IPCC's Fifth Assessment Report (AR5). 

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