Historical emissions are based on 2020 National inventory report (UNFCCC, 2020), which is aligned with the inventory emissions developed by the U.S. Environmental Protection Agency (U.S. Environmental Protection Agency, 2020b). The last available historical data year is 2018.
NDC and other targets
For the 2020 pledge, NDC, and long-term target, we apply the indicated reduction to the 2005 base year including LULUCF, and then subtract the projected emissions for the LULUCF sector.
The LULUCF emission projections up to 2030 were taken from the 6th National Communication, which reported sinks of 0.6–0.9 GtCO2e/year in 2025 (U.S. Department of State, 2014). The 2016 CAT update used LULUCF projections from the 2nd Biennial report, which reported a sink of 0.9–1.2 GtCO2e/year in the same year (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 USA has not submitted its 7th National Communication, which was due on 1 January 2018, therefore more recent LULUCF projections are not available.
The LULUCF projections for 2050 were taken from the Mid-Century Strategy document and represent the full range of modelled sink scenarios in the report (The White House, 2016b).
Current policy projections
The pre-COVID-19 current policy projection was done in three steps, to which our assessment of the impacts of the pandemic were added:
- First, we estimate the baseline for total emissions projections under current policies as the aggregation and harmonisation of three components:
- Energy-related CO2 emissions: The projections were taken from EIA’s Annual Energy Outlook 2020 (U.S. Energy Information Administration, 2020a), which includes all policies in place until end of September 2019. 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 July 2020 (U.S. Congressional Budget Office, 2020).
- Industrial process CO2: The emissions were projected by applying projected production growth of the main industries in terms of emissions (i.e. cement, chemical and iron and steel industries), taken from EIA’s Annual Energy Outlook 2020, to their respective emissions in the base year.
- Other GHG emissions: The projections were updated and taken 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 2019 (U.S. Environmental Protection Agency, 2019b). We did not consider alternative economic growth scenarios for other GHG emissions.
- 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 historical inventory data. Note that the impact of COVID-19 in GHG emissions was not considered until this point.
- Third, the quantification of two policy rollbacks 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 weaker fuel efficiency standards for light-duty vehicles (SAFE): We projected the additional fuel consumption in passenger vehicles and light truck due to the weaker fuel efficiency standards for the model years 2021–2026. In order to derive the additional fuel consumption, we took as reference the projections of relevant transportation indicators from the reference case of EIA’s Annual Energy Outlook 2020, such as average miles per gallon, vehicle-miles travelled (VTM) and new vehicles sales. The resulting additional emissions where calculated using the carbon intensity of fuel consumption used in the official rule (U.S. Environmental Protection Agency & U.S. National Highway Safety Administration, 2020).
- 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/yr in 2025 and by 78–101 MtCO2e/yr 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 non-CO2 emissions projections. Moreover, California, Vermont and Washington state have adopted measures to backstop the SNAP rollback within their own jurisdictions (World Resources Institute, 2020). These factors may imply that the quantification approach assumed here may overestimate the effect of the rollback.
- These emissions ranges are added up to the baseline projections. Linear interpolation is used for the gap years in between.
We applied a novel method to estimate the COVID-19 related dip in greenhouse gas emissions in 2020 and the deployment through to 2030. The uncertainty surrounding the severity and length of the pandemic creates a new level of uncertainty for current and future greenhouse gas emissions. We first update the current policy projections using most recent projections, prepared before the pandemic (as outlined in the previous section).
For energy-related CO2 emissions, we used the revised projections in the July US EIA’s short-term energy outlook for 2020-2021 (U.S. Energy Information Administration, 2020f). These projections incorporate the effects of reduced economic activity related to the COVID-19 pandemic and the changes caused in energy supply and demand patterns in 2020-2021, e.g. reduction in vehicle fuel consumption, electricity consumption and generation, commercial and residential energy use, domestic aviation.
We then distil the emissions intensity (GHG emissions/GDP) from the pre‑pandemic scenario and apply to it most recent GDP projections that take into account the effect of the pandemic in non-energy CO2 and other GHG emissions. To capture a wide range, we draw on projections from the IMF and the US Congressional Budget Office (CBO). The IMF projects a reduction in GDP of 8% in 2020 compared to 2019, followed by an increase of 4.5% in 2021 (IMF, 2020). Since IMF projections only provide values for the next few years, we use the growth rates for the AEO’s scenarios from 2022 until 2030. The CBO projections are available until 2030 (U.S. Congressional Budget Office, 2020).
As of June, 2020, 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.