USA

Historical emissions are based on the 1990-2019 National inventory report (UNFCCC, 2021), which is aligned with the inventory emissions developed by the U.S. Environmental Protection Agency (U.S. Environmental Protection Agency, 2021a).

Emissions in 2020 were estimated on a sector-by-sector basis.

• Total GHG emissions in the energy sector were extended to 2020 using the growth rate of energy-related CO₂ emissions in 2020 reported in the June EIA monthly energy review, which includes the impact of the COVID-19 pandemic (U.S. Energy Information Administration, 2021d).
• The estimation of emissions in industrial processes was split by type of industry. Greenhouse gas emissions in the mineral, chemical and metal industries were extended to 2020 using the growth rate of CO₂ emissions in the industry sector in 2020 reported in the June EIA monthly energy review, which includes the impact of the COVID-19 pandemic (U.S. Energy Information Administration, 2021d). The rest of industry processes GHG emissions followed the projected growth of non-CO₂ emissions in 2020 taken from the Global Non-CO₂ Greenhouse Gas Emission Projections & Mitigation Potential: 2015–2050, based on the baseline scenario (U.S. Environmental Protection Agency, 2015).
• GHG emissions in the agriculture and waste sectors were extended to 2020 using the trend of historical emissions in the last 5 years (2015-2019).

2020 pledge

For the 2020 pledge, we apply the indicated target of 17% reduction to the 2005 base year including LULUCF, and then subtract the projected emissions for the LULUCF sector. The LULUCF emission projections in 2020 were taken from the 6th National Communication, which reported sinks of 0.6–0.9 GtCO₂e/year in 2020 (U.S. Department of State, 2014).

The 2016 CAT update used LULUCF projections from the 2nd Biennial report (Climate Action Tracker, 2016b; U.S. Department of State, 2016). The sinks in the 2nd Biennial report were calculated with a different methodology than LULUCF in the historical inventory data reported to UNFCCC for 2005, on which the2020 pledge is based, making these values incompatible with the historical data. We have therefore returned to using projections from the 6th National Communication, which is consistent with the historical data.

The US has not submitted its 7th National Communication, which was due on 1 January 2018, therefore more recent LULUCF projections are not available.

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 6th National Communication, which reported sinks of 0.5–0.9 GtCO₂e/year in 2030 (U.S. Department of State, 2014).

The 2016 CAT update used LULUCF projections from the 2nd Biennial report (Climate Action Tracker, 2016b; U.S. Department of State, 2016). The sinks in the 2nd Biennial report were calculated with a different methodology than LULUCF in the historical inventory data reported to UNFCCC for 2005, on which the NDC target is based, making these values incompatible with the historical data. We have therefore returned to using projections from the 6th National Communication, which is consistent with the historical data.

The US has not submitted its 7th National Communication, which was due on 1 January 2018, therefore more recent LULUCF projections are not available.

2050 Net-zero target

For the 2050 net-zero target, which we interpret as covering all GHGs, we assume total GHG emissions in 2050 are balanced with the projected sinks in 2050. The LULUCF emissions in 2050 were projected using a linear trend extrapolation of 1990-2019 historical emissions in LULUCF based on the National inventory report (UNFCCC, 2021). The extrapolation results in sinks of 0.6 GtCO₂e/year in 2050.

The US has not submitted its 7th National Communication, which was due on 1 January 2018, therefore more recent LULUCF projections are not available.

The current policy projection was done in three steps:

• First, we estimate the baseline for total emissions projections under current policies as the aggregation and harmonisation of energy, industry, agriculture, and waste sectors:
  • GHG emissions in the energy sector:
    • GHG emissions in the energy sector are based on energy-related CO₂ emissions projections: Short-term projections (2021-2022) were taken from the June EIA monthly energy review (U.S. Energy Information Administration, 2021d). These projections are harmonised with long-term projections (2022-2030) from EIA’s Annual Energy Outlook 2021 (U.S. Energy Information Administration, 2021a), which includes all policies in place until end of October 2020.
    • 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. The economic growth assumptions in the reference scenario are broadly aligned with the long‑term economic projections by the Congressional Budget office in February 2021 (U.S. Congressional Budget Office, 2021).
    • The resulting CO₂ emissions projections are used to calculate growth rates that are applied to all GHGs energy sector emissions.
  • 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 2021 (U.S. Energy Information Administration, 2021a), to their respective GHG emissions in the base year.
    • Projections in the rest of industry processes apply the growth rates from industrial process F-gas emissions from the Global Non‑CO₂ Greenhouse Gas Emission Projections & Mitigation Potential: 2015–2050, based on the baseline scenario, which includes policies that were implemented through until early 2015 (U.S. Environmental Protection Agency, 2015).
    • We did not consider alternative economic growth scenarios for GHG emissions in industry processes.
  • GHG emissions in agriculture and waste sectors follow the growth rates of the respective sector in the Global Non‑CO₂ Greenhouse Gas Emission Projections & Mitigation Potential: 2015–2050, based on the baseline scenario (U.S. Environmental Protection Agency, 2015). We did not consider alternative economic growth scenarios for GHG emissions in agriculture and waste sectors.
• Second, all the aforementioned emissions were aggregated and then harmonised to historical data by applying the annual percentage change estimated from the projected dataset to the base year. Note that the impact of COVID-19 in GHG emissions is considered in energy-related CO₂ emissions and industrial process emissions in mineral, chemical and metal industries (using EIA’s Annual Energy Outlook 2021 as reference).
• Third, the quantification of a policy rollback was incorporated in the baseline projections (which were not part of the policies considered in the baseline scenario taken from EIA’s Annual Energy Outlook 2020 and the Global Non-CO₂ Greenhouse Gas Emission Projections & Mitigation Potential:
  • The non-enforcement of the SNAP program regarding the use of HFC: The original SNAP rule was estimated to reduce emissions by 54–64 MtCO₂e/year in 2025 and by 78–101 MtCO₂e/year in 2030 in comparison to a business as usual scenario (U.S. Environmental Protection Agency, 2015). Note that the avoided emissions were estimated in 2015, with data closer to the 2nd BUR estimations than the current EPA projections, which was the reference data to estimate industry processes emissions projections. We downscale the anticipated reductions by comparing the original 2015 business-as-usual scenario with our F-gases emissions projections calculated above (industrial processes GHG emissions) and then calculate the proportional reduction. The downscale results in additional emissions 30–35 MtCO₂e/year in 2025 and by 40–52 MtCO₂e/year in 2030.
  • These emissions ranges are added up to the baseline projections. Linear interpolation is used for the gap years in between.

As of June, 2021, the US had still not submitted its third Biennial Report and 7th National Communication to the UNFCCC, the deadline for which was 1 January 2018. One implication of this failure to report is that it makes it more difficult for independent analysts, like the Climate Action Tracker, to accurately assess future emissions development in the US, particularly for non-energy CO₂ and non-CO₂ emissions.

The planned policy projections take the current policy projections (upper and lower bounds) as starting point. Then the mitigation potential of the following policy proposals is quantified and subtracted from the current policy range:

• Stricter fuel economy and GHG emissions standards for passenger vehicles for model years 2023-2026, reaching 52 miles per gallon (mpg) in 2026.
  • The annual mitigation potential of greenhouse emissions until 2030 is directly extracted from the official impact assessment of the proposed rule. The rule estimates a reduction in emissions of 46 MtCO₂e/year in 2030 (U.S. Environmental Protection Agency, 2021f)
• Phase down in the production and consumption of hydrofluorocarbons (HFCs) by 85% over the next 15 years.
  • The annual mitigation potential is calculated as a linear interpolation between zero in 2022, year when the rule is expected to take place and 187 MtCO₂e in 2036 (reflecting the 85% phase down in 15 years) (U.S. Environmental Protection Agency, 2021c).

The implementation of these two policies would lead to 2% reduction in emissions in 2030 compared to current policy projections