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Ambition gap

What is The United Statesʼ pathway to limit global warming to 1.5°C?

1.5°C compatible pathways

Although the US’ updated NDC shows an increase in ambition, now targeting 50-52% reductions below 2005 levels by 2030, it is not yet consistent with a 1.5˚C compatible pathway. Our analysis indicates that the US would need to upgrade its new NDC target to reduce emissions to 60% below 2005 levels by 2030 to be 1.5˚C compatible.

US current policies (as of April 2021) are insufficient to achieve its updated NDC target.

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 for emission reductions 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 LULUCF on top of its reductions.1

Long term pathway

The Biden climate plan aims to reach net zero emissions by 2050. By mid-century, in a Paris compatible pathway, GHG emissions should not be higher than 0.3-0.7 GtCO₂e or around 90-96% below 2005 levels excluding land sinks but including the use of BECCS.9 When land sinks are assumed to remain at their current level into the future, the US would reach net zero GHG emissions between 2040 and 2050.10 To achieve net zero GHGs by mid-century, the US would need additional carbon removal from LULUCF or technology options at a level of 0.3-0.7 GtCO₂/yr by 2050.11

While the energy sector emissions reach net zero (including the use of BECCS) 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.

1 Climate Action Tracker. To show climate leadership, US 2030 target should be at least 57-63% – Mar 2021. (2021).

2 Biden for President. The Biden plan to build a modern, sustainable infrastructure and an equitable clean energy future. (2020).

3 Climate Action Tracker. USA | Climate Action Tracker. (2021).

4 The United States of America. The United States of America – Nationally Determined Contribution.

5 NCSL. State Renewable Portfolio Standards and Goals. (2020).

6 Barbose, G. U.S. Renewables Portfolio Standards 2019 Annual Status Update.

7 Climate Action Tracker. United States of America. CAT July 2020 Update. (2020).

8 Gopinathan, N., Subramanian, N. S. & Urpelainen, J. Mid-Century Strategies: pathways to a low-carbon future? Clim. Policy 19, 1088–1101 (2019).

9 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.

10 In some of the analysed pathways, the energy sector assumes already a certain amount of carbon dioxide removal technologies, in this case bioenergy carbon capture and storage (BECCS).

11 When considering historical LULUCF sinks (-765 MtCO₂e on average between 2008-2018), the Mid-Century Strategy projects a level of LULUCF sinks of -409 MtCO₂e by 2050 which would lead to net zero GHGs by 2056.7,8

Methodology

The United Statesʼ total GHG emissions

excl. LULUCF MtCO₂e/yr

Displayed values
Reference year
−120%−100%−80%−60%−40%−20%0%19902010203020502070
Reference year
2005
1.5°C emissions level
−62%
NDC
−50%
Ambition gap
−11%
  • 1.5°C compatible pathways
  • Middle of the 1.5°C compatible range
  • Current policy projections
  • 1.5°C emissions range
  • Historical emissions
2030 emissions levels
Current policy projections
NDC
1.5°C emissions level
Ref. year 2005
7 423MtCO₂e/yr

Energy system transformation

The required decline of CO₂ emissions would need to come mainly from the decarbonisation of the country’s energy mix. Across most analysed pathways, this requires fossil fuel consumption to be more than halved by 2030 from more than 80% of the primary energy mix in 2017. To support this decarbonisation pathway, renewable energy needs to ramp up from 8% of the total primary energy mix in 2017 and increase threefold by 2030. Some models show a penetration of negative CO₂ emissions technologies such as BECCS by 2030, implying that the country would need to plan their development in the next few years.

Methodology

The United Statesʼ primary energy mix

petajoule per year

Scaling
SSP1 Low CDR reliance
201920302040205040 00060 00080 000
SSP1 High CDR reliance
201920302040205040 00060 00080 000
Low Energy Demand
201920302040205040 00060 00080 000
High Energy Demand - Low CDR reliance
201920302040205040 00060 00080 000
  • Negative emissions technologies via BECCS
  • Unabated fossil
  • Renewables incl. Biomass
  • Nuclear and/or fossil with CCS

The United Statesʼ total CO₂ emissions

excl. LULUCF MtCO₂/yr

−2 00002 0004 0006 00019902010203020502070
  • 1.5°C compatible pathways
  • 1.5°C emissions range
  • Middle of the 1.5°C compatible range
  • Historical emissions

1.5°C compatible emissions benchmarks

Key emissions benchmarks of Paris compatible Pathways for The 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
Indicator
2005
Reference year
2019
2030
2040
2050
Year of net zero GHG
incl. BECCS excl. LULUCF and novel CDR
Total GHG
Megatonnes CO₂ equivalent per year
7 423
6 558
2 844
2 518 to 3 280
1 225
721 to 1 656
578
101 to 813
2052
Relative to reference year in %
−62%
−66 to −56%
−83%
−90 to −78%
−92%
−99 to −89%
Total CO₂
MtCO₂/yr
6 139
5 268
2 386
1 747 to 2 648
761
105 to 1 215
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%

Footnotes