USA

Overall rating
Insufficient

Policies and action
against modelled domestic pathways

Insufficient
< 3°C World

NDC target
against modelled domestic pathways

Almost Sufficient
< 2°C World

NDC target
against fair share

Insufficient
< 3°C World
Climate finance
Critically insufficient
Net zero target

year

2050

Comprehensiveness rated as

Average
Land use & forestry
Not significant

Historical emissions

Historical emissions are based on the 1990–2021 National Inventory Report (U.S. Government, 2023), which is aligned with the inventory emissions developed by the US Environmental Protection Agency (U.S. Environmental Protection Agency, 2023b). The national inventory was reported in AR5 Global Warming Potential (GWP) values. We converted all values to AR4 GWP.

2022 historical emissions estimate

Emissions in 2022 were estimated on a sector-by-sector basis.

  • Total GHG emissions in the energy sector were estimated for 2022 based the energy-related CO2 emissions reported in the October-2023 Energy Information Administration (EIA) Short-term Outlook (U.S. Energy Information Administration, 2023n), and non-CO2 emissions in the energy sector from the US State-level Non-CO2 Greenhouse Gas Mitigation Potential: 2025–2050 (US Environmental Protection Agency, 2022a). Total GHG emissions in the energy sector in 2022 were harmonised to 2021 using the growth rate of the sum of CO2 (based on historic values) and non-CO₂ emissions (based on our estimation) .
  • The estimation of emissions in industrial processes was split by type of industry. GHG emissions in the mineral, chemical and metal industries were extended to 2022 using the growth rate of energy-related CO2 emissions in the industry sector in 2022 reported in the Oct-2023 EIA’s Short-term Outlook (U.S. Energy Information Administration, 2023n). The remaining GHG emissions from industry processes followed the growth of the economy based on the GDP growth rate in 2022 (U.S. Bureau of Economic Analysis, 2023).
  • GHG emissions in the agriculture and waste sectors were extended to 2022 using the trend of historical emissions in the last 5 years (2017–2021).

NDC and other targets

2030 NDC target

For the 2030 NDC target, we apply the indicated target of 50%–52% reduction to the 2005 base year including LULUCF, and then subtract the projected emissions for the LULUCF sector. The LULUCF emission projections in 2030 were taken from the 5th Biennial Report which reported sinks of 0.6–0.8 GtCO2e/year in 2030 (U.S. Department of State, 2022).

2050 Net-zero target

For the net-zero target, we assume total GHG emissions in 2050 are balanced by projected sinks in 2050. The LULUCF sinks in 2050 were taken from the US long-term strategy (LTS) submitted to the UNFCCC in November 2021 (U.S. Department of State, 2021). Since the document does not provide exact figures, we have extracted the approximated figures from the graphs in the report. The reading of the graphs results in an approximation of minus 0.6–1.4 GtCO2e/year for LULUCF sinks in 2050, we add this sink to the residual estimate in 2050 to get 0.6–1.5 GtCO2e/year in 2050. We include also estimates for 2040 in our pathway using a similar approach.

Current policy projections

The current policy projections were done in four steps:

  • First, we estimate the baseline for total emissions projections under current policies as the aggregation of the energy, industry, agriculture, and waste sectors:
    • GHG emissions in the energy sector:
      • Energy-related CO2 emissions projections: Short-term projections (2023–2024) were taken from the Oct-2023 EIA’s Short-term Outlook (U.S. Energy Information Administration, 2023n). These projections are harmonised with long-term projections (2024—2030) from the EIA’s Annual Energy Outlook 2023 (U.S. Energy Information Administration, 2023c), which includes all policies in place until the mid of November 2022, notably the implementation of the Inflation Reduction Act (IRA) and new Corporate Average Fuel Economy (CAFÉ) Standards for Model Years 2024–2026 Passenger Cars and Light Trucks. We use two scenarios from the Annual Energy Outlook – the reference scenario and the low economic growth scenario – to create a range of emissions projections.
      • Non-CO2 emissions in the energy sector from the U.S. State-level Non-CO2 Greenhouse Gas Mitigation Potential: 2025–2050 (US Environmental Protection Agency, 2022b)
      • All GHGs emissions in the energy sector result from the sum of the two points above (CO2 and non-CO2). The resulting projections are harmonised to the latest historical year using growth rates.
    • Industrial processes GHG emissions: the projection of GHG emissions in industrial processes was split by type of industry
      • GHG emissions in the mineral, chemical and metal industries were projected by applying projected production growth of each industry in terms of value of shipments taken from EIA’s Annual Energy Outlook 2023(U.S. Energy Information Administration, 2023c), to their respective GHG emissions in the base year. We use two scenarios from the Annual Energy Outlook – the reference scenario and the low economic growth scenario – to create a range of emissions projections
      • Projections in the rest of industry processes apply the growth rates from industrial process F-gas emissions from the U.S. State-level Non-CO2 Greenhouse Gas Mitigation Potential: 2025–2050, which includes policies that were implemented until early 2015 (US Environmental Protection Agency, 2022b).
    • GHG emissions in the agriculture and waste sectors follow the growth rates of the respective sector in the U.S. State-level Non-CO2 Greenhouse Gas Mitigation Potential: 2025–2050 (US Environmental Protection Agency, 2022b). We did not consider alternative economic growth scenarios for GHG emissions in the agriculture and waste sectors.
  • Second, each of the above emissions categories were harmonised to historical data for each sector by applying the estimated annual percentage change from the projected dataset to the base year. The projections for all sectors were then aggregated to obtain total GHG emissions, excluding LULUCF. These projections are the baseline scenarios.
  • Third, the quantification of the Inflation Reduction Act (IRA) in non-CO2 emissions and in non-energy sectors:
    • Non-CO2 emissions: The AEO2023 already accounts for energy-related CO2 emissions (~97% of total CO2 emissions). The IRA has also the potential to reduce non-CO2 GHG emissions that are not quantified in the baseline scenarios explained above. The quantification of such impact is based on the assessment of this policy on total GHG emissions (ZERO Lab, 2023). We use the mitigation potential range of IRA on non-CO2 emissions reported for years 2022, 2030 and 2035 and made a linear interpolation for the years in between. The resulting mitigation potential for each year is discounted to the corresponding year of the baseline scenarios (the mitigation effect is between 50-100 MtCO2e in 2030 and beyond).
    • Non-energy CO2 emissions: The IRA has also the potential to reduce CO2 emissions in non-energy sectors, mainly Industry Processes and Product Use (IPPU), and which are not quantified in the baseline scenarios explained above. We assume that such emissions reductions will be achieved mainly through Carbon Capture, Use and Storage (CCUS). The quantification of such impact is based on the assessment of IRA on mitigation potential of CCUS in the study done by (Rhodium Group, 2022). We assume a range of mitigation potential between zero, to capture the uncertainty around the deployment of the technology, and the mitigation potential reported in 2030 and 2035, assuming a start of emissions reduction in 2025. We made a linear interpolation for the years in between. The resulting mitigation potential for each year is discounted to the corresponding year of the baseline scenarios (the mitigation effect could be up to 100 MtCO2e in 2030 and 300 MtCO2e in 2035).
  • Fourth, the quantification of the AIM Act, which was not part of the policies considered in the baseline scenario taken from Global Non-CO2 Greenhouse Gas Emission Projections & Mitigation Potential:
    • Phase down of the production and consumption of hydrofluorocarbons (HFCs) by 85% over the next 15 years. The annual mitigation potential is calculated as a range of between two mitigation potential trajectories for HFC emissions:
      • The first one is based on the HFCs emissions projection reported in the 5th Biennial Report in 2020, 2030, 2035, and 2040 (U.S. Department of State, 2022), which considers the implementation of the AIM Act, although does not achieve the proposed target. After harmonising the projections with the latest historical year, we interpolated the years in between and calculated the annual mitigation potential against the baseline scenario.
      • The second one is based directly on the annual HFCs consumption caps defined in the AIM Act (U.S. Environmental Protection Agency, 2021a). We then calculated the mitigation potential against the baseline scenario.
    • The resulting mitigation potential range for each year is discounted to the corresponding year of the baseline scenarios. The mitigation effect of this modification is between 50–150 MtCO2e in 2030 and 100–200 MtCO2e in 2035

The CAT current policy projections for energy-related CO2 emissions are based on the EIA’s Annual Energy Outlook 2023 (U.S. Energy Information Administration, 2023c), which includes the following state level policies*:

Selected state level policies included in CAT projections
• California Global Warming Solutions Act of 2006 (SB32)
• California’s cap and trade system (California Global Warming Solutions Act)
• California’s Advanced Clean Cars program including the Zero Emissions Vehicle program.
• 31 State Renewable Portfolio Standards and the District of Columbia Renewable Portfolio Standards
Illinois, North Carolina, Nebraska, and Rhode Island enacted new legislation in 2022 for their respective clean energy standards (CES) programs
• Northeast Regional Greenhouse Gas Initiative
• State motor fuels taxes
State-level clean energy standards (CES) targets for Colorado, Connecticut, Louisiana, Massachusetts, Michigan, New Jersey, and Wisconsin

*Note: Policies highlighted in bold are new compared to last year’s assessment

CAT Methodology

Since the last assessment, the CAT has updated its methodology and pathways included for deriving modelled domestic pathways. As a result, there have been changes in the pathways for some countries, particularly for pathways that hold warming below 3°C. For the full CAT methodology click here.

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