USA

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Critically Insufficient4°C+ World

NDCs with this rating fall well outside of a country’s “fair share” range and are not at all consistent with holding warming to below 2°C let alone with the Paris Agreement’s stronger 1.5°C limit. If all government NDCs were in this range, warming would exceed 4°C. For sectors, the rating indicates that the target is consistent with warming of greater than 4°C if all other sectors were to follow the same approach.

Highly insufficient< 4°C World

NDCs with this rating fall outside of a country’s “fair share” range and are not at all consistent with holding warming to below 2°C let alone with the Paris Agreement’s stronger 1.5°C limit. If all government NDCs were in this range, warming would reach between 3°C and 4°C. For sectors, the rating indicates that the target is consistent with warming between 3°C and 4°C if all other sectors were to follow the same approach.

Insufficient< 3°C World

NDCs with this rating are in the least stringent part of a country’s “fair share” range and not consistent with holding warming below 2°C let alone with the Paris Agreement’s stronger 1.5°C limit. If all government NDCs were in this range, warming would reach over 2°C and up to 3°C. For sectors, the rating indicates that the target is consistent with warming over 2°C and up to 3°C if all other sectors were to follow the same approach.

2°C Compatible< 2°C World

NDCs with this rating are consistent with the 2009 Copenhagen 2°C goal and therefore fall within a country’s “fair share” range, but are not fully consistent with the Paris Agreement long term temperature goal. If all government NDCs were in this range, warming could be held below, but not well below, 2°C and still be too high to be consistent with the Paris Agreement 1.5°C limit. For sectors, the rating indicates that the target is consistent with holding warming below, but not well below, 2°C if all other sectors were to follow the same approach.

1.5°C Paris Agreement Compatible< 1.5°C World

This rating indicates that a government’s NDCs in the most stringent part of its “fair share” range: it is consistent with the Paris Agreement’s 1.5°C limit. For sectors, the rating indicates that the target is consistent with the Paris Agreement’s 1.5°C limit.

Role model<< 1.5°C World

This rating indicates that a government’s NDC is more ambitious than what is considered a “fair” contribution: it is more than consistent with the Paris Agreement’s 1.5°C limit. No “role model” rating has been developed for the sectors.

1.5°C Compatible< 1.5°C World

Global Warming Potentials

Climate Action Tracker assessments before December 2018 used the global warming potentials (GWPs) from the IPCC’s Second Assessment Report (SAR). At that time, we updated all figures and time series to GWPs from the Fourth Assessment Report (AR4). For the USA, this resulted in higher estimated emissions levels for historical data, pledges, and emissions projections.

Historical emissions

Historical emissions are 2019 inventory emissions developed by the U.S. Environmental Protection Agency (U.S. Environmental Protection Agency, 2019). The last available historical year is 2017.

Pledges

Targets for 2020 and 2025 were calculated from the 2019 national inventory submissions.

For the 2020 pledge, NDC, and long-term target, we apply the indicated reduction to the 2005 inventory data for 2005 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 to 1.2 GtCO2e/year in the same year (Climate Action Tracker, 2016b; U.S. Department of State, 2016). The methodological changes in the 2nd Biennial Report increased the sink from forest and land use by about 4.3 to 5.1%-points compared to the total emission level in the base year, 2005, rendering the target for the remaining sectors 3.9 to 4.6%-points easier to achieve. The sinks in the 2nd Biennial report were calculated with a different methodology than LULUCF in the CRF historical data 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 LULUCF projections for 2050 were taken from the Mid-Century Strategy document and represent the full range of modeled sink scenarios in the report (The White House, 2016).

Current policy projections

The current policy projection was done in four steps:

First, energy-related CO2 emissions projections were taken from EIA’s Annual Energy Outlook 2019 (U.S. Energy Information Administration, 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 lower than those projected by the Congressional Budget office in May 2019 (U.S. Congressional Budget Office, 2019), but are broadly aligned with historical trends.
Second, industrial process CO2 emissions were projected by applying the historical ratio (2000-2015) of industrial process CO2 emissions to projections of industrial energy related emissions from the Annual Energy Outlook 2019 Reference Case.
Third, other GHG emission projections were taken from the 2nd Biennial Report, based on the Current Measures scenario, which includes policies that were implemented through mid-2015 (U.S. Department of State, 2016) . We did not consider alternative economic growth scenarios for other GHG emissions.
Fourth, 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.

As of May 27, 2019, the US had still not submitted its third Biennial Report to the UNFCCC, the deadline for which was the end of 2017. One implication of this failure to report is that it makes it more difficult for domestic and international organisations, like the Climate Action Tracker, to accurately assess future emissions development in the US, particularly for non-energy CO2 and non-CO2 emissions.