We rate the USA’s mitigation efforts as “Critically insufficient” due to the fact that it is withdrawing from the Paris Agreement, and hence annulling its NDC.
However, if the CAT were to rate the US NDC of 26–28% below 2005 levels by 2025 (incl. LULUCF), it would be rated “Insufficient.” The “Insufficient” rating indicates that the US’s NDC in 2025 is not consistent with holding warming to below 2°C, let alone limiting it to 1.5°C as required under the Paris Agreement, and is instead consistent with warming between 2°C and 3°C. If all countries were to follow this approach, warming would reach over 2°C and up to 3°C. This means the US’s NDC is at the least stringent end of what would be a fair share of global effort, and is not consistent with the Paris Agreement’s 1.5˚C limit, unless other countries make much deeper reductions and comparably greater effort.
Reaching the NDC target would have required implementing additional policies under the Obama Administration’s Climate Action Plan, which President Trump has rescinded.
The NDC target for 2025 could be considered a fair contribution to 2°C only from a very selective perspective. With the perspective that countries should have similar emissions reduction costs per GDP (effort sharing approaches that focus on capability and costs), the US NDC could be considered 2°C compatible because costs to reduce emissions in the USA, while keeping the high consumption levels, are high compared to other countries. However, considering the USA’s high historical emissions, high per capita emissions and high capability to act (approaches that focus on equality, equal cumulative emissions and historical responsibility), the NDC is highly inequitable and much more stringent reductions would be required and partially result in negative emission allowances in all years.
If the CAT were to rate the USA’s projected emissions levels in 2025 under current policies, we would rate the USA “Highly insufficient,” indicating that the USA’s current policies in 2025 are not consistent with holding warming to below 2°C, let alone limiting it to 1.5°C as required under the Paris Agreement, and are instead consistent with warming between 3°C and 4°C: if all countries were to follow the US’s approach, warming could reach over 3°C and up to 4°C. This means the USA’s current policies are not in line with any interpretation of a “fair” approach to the former 2°C goal, let alone the Paris Agreement’s 1.5°C limit.
Further information about the risks and impacts associated with the temperature levels of each of the categories is available here.