Ambition Gap

1.5°C compatible pathways

Although the US’ updated NDC shows an increase in ambition, now targeting a 50–52% reduction in total GHG emissions below 2005 levels by 2030 including LULUCF (equivalent to 44–47% excluding LULUCF), it is not yet consistent with a 1.5˚C compatible pathway.¹ Our analysis indicates that the US would need to increase its new NDC emissions reduction target to 62% below 2005 levels by 2030 to be 1.5˚C compatible (excl. LULUCF).

The country’s current policies (as of August 2022) are insufficient to achieve its updated NDC target; however, the Inflation Reduction Act (IRA) included in the assessment significantly narrowed the gap.²

A fair share contribution to reduce global greenhouse gas emissions compatible with the Paris Agreement would require the US to go further than its domestic target, and provide substantial support to developing countries. The Climate Action Tracker assesses that the US’ fair share (domestic and international support) would require the country to provide support for mitigation abroad equivalent to domestic emissions reductions of at least 75% below 2005 levels by 2030 when excluding LULUCCF on top of its domestic reductions.³

United States' total GHG emissions excl. LULUCF MtCO₂e/yr

Displayed values

Percent
MtCO₂e/yr

Reference Year

2005
2010
2015

*Net zero emissions excl LULUCF is achieved through deployment of BECCS; other novel CDR is not included in these pathways

Graph description

The figure shows national 1.5°C compatible emissions pathways. This is presented through a set of illustrative pathways and a 1.5°C compatible range for total GHG emissions excl. LULUCF. The 1.5°C compatible range is based on global cost-effective pathways assessed by the IPCC SR1.5, defined by the 5th-50th percentiles of the distributions of such pathways which achieve the LTTG of the Paris Agreement. We consider one primary net-negative emission technology in our analysis (BECCS) due to data availability. Net negative emissions from the land-sector (LULUCF) and novel CDR technologies are not included in this analysis due to data limitations from the assessed models. Furthermore, in the global cost-effective model pathways we analyse, such negative emissions sources are usually underestimated in developed country regions, with current-generation models relying on land sinks in developing countries.

Methodology
- Underlying global pathways
- Downscaling of global pathways
Data References

Long term pathway

The US long term strategy (LTS) aims to reach net zero emissions by 2050.⁴ By mid-century, in a Paris Agreement compatible pathway, GHG emissions should not be higher than 0.1–0.8 GtCO₂e/yr or around 89–99% below 2005 levels excluding land sinks but including the use of BECCS.⁵

While the energy sector could be fully decarbonised as early as 2038, remaining emissions, mostly from agriculture and waste sectors, will need to be balanced with negative CO₂ emissions through the deployment of carbon dioxide removal (CDR) approaches.

Graph description

Primary energy mix composition in consumption (EJ) and shares (%) for the years 2030, 2040 and 2050 based selected global least cost pathways.

Methodology
- Downscaling primary energy mix
Data References
- Historical energy consumption : IEA WEB 2021

Energy system transformation

The required CO₂ emissions cuts would need to come mainly from the decarbonisation of the country’s energy mix. Across most analysed pathways, this requires absolute fossil fuel consumption to be more than halved by 2030 from more than 80% of the primary energy mix in 2019. To support this decarbonisation pathway, renewable energy needs to increase from 8% of the total primary energy mix in 2019 to 21-46% by 2030. Some models show a penetration of negative CO₂ emissions technologies such as BECCS by 2030, implying that the country may need to plan their development in the next few years.

Graph description

1.5°C compatible CO₂ emissions pathways. This is presented through a set of illustrative pathways and a 1.5°C compatible range for total CO₂ emissions excl. LULUCF. The 1.5°C compatible range is based on global cost-effective pathways assessed by the IPCC SR1.5, defined by the 5th and 5th percentiles.

Methodology
- Downscaling CO2 Emissions
Data References
- Historical emissions: PRIMAP-Hist 2021. Last inventory year: 2019.

1.5°C compatible emissions benchmarks

Key emissions benchmarks of Paris compatible Pathways for United States. The 1.5°C compatible range is based on the Paris Agreement compatible pathways from the IPCC SR1.5 filtered with sustainability criteria. The median (50th percentile) to 5th percentile and middle of the range are provided here. Relative reductions are provided based on the reference year.

Reference Year

2005
2010
2015

Indicator	2005 Reference year	2019	2030	2040	2050	Year of net zero incl. BECCS excl. LULUCF and novel CDR
Total GHG Megatonnes CO₂ equivalent per year	7435	6572	2844 2518 to 3280	1225 721 to 1656	578 101 to 813
Relative to reference year in %			-62% -66 to -56%	-84% -90 to -78%	-92% -99 to -89%
Total CO₂ MtCO₂/yr	6149	5279	2386 1747 to 2648	761 105 to 1215	41 -278 to 382	2055 2043 to 2063
Relative to reference year in %			-61% -72 to -57%	-88% -98 to -80%	-99% -105 to -94%

All information excluding LULUCF emissions and novel CDR approaches. BECCS are the only carbon dioxide removal (CDR) technologies considered in these benchmarks
All values are rounded

Methodology
- How are emissions bencharmks defined?
Data References
- Historical emissions: Climate Action Tracker 2022 update
- Download data as CSV

Climate Action Tracker & New Climate Institute. USA | Climate Action Tracker. 2022. ↩
Rep. Yarmuth, J. A. H.R.5376 - Inflation Reduction Act of 2022. (117th Congress, 2022). ↩
Climate Action Tracker. To show climate leadership, US 2030 target should be at least 57-63% - Mar 2021. (2021). ↩
U.S. Department of State. The Long-Term Strategy of the United States: Pathways to Net-Zero Greenhouse Gas Emissions by 2050. 2021. ↩
While global cost-effective pathways assessed by the IPCC Special Report 1.5°C provide useful guidance for an upper-limit of emissions trajectories for developed countries, they underestimate the feasible space for such countries to reach net zero earlier. The current generation of models tend to depend strongly on land-use sinks outside of currently developed countries and include fossil fuel use well beyond the time at which these could be phased out, compared to what is understood from bottom-up approaches. The scientific teams which provide these global pathways constantly improve the technologies represented in their models - and novel CDR technologies are now being included in new studies focused on deep mitigation scenarios meeting the Paris Agreement. A wide assessment database of these new scenarios is not yet available; thus, we rely on available scenarios which focus particularly on BECCS as a net-negative emission technology. Accordingly, we do not yet consider land-sector emissions (LULUCF) and other CDR approaches which developed countries will need to implement in order to counterbalance their remaining emissions and reach net zero GHG are not considered here due to data availability. ↩

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

1.5°C compatible pathways

United States' total GHG emissions excl. LULUCF MtCO₂e/yr

Long term pathway

United States' primary energy mix

petajoule per year

Energy system transformation

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

1.5°C compatible emissions benchmarks

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