In this Mitigation and Adaptation Strategies for Global Change publication, we find that the total impact of the updated unconditional and conditional NDCs of these countries on global emission levels by 2030 is an additional reduction of about 3.8 and 3.9 GtCO2eq, respectively, compared to the previously submitted NDCs. However, this total reduction must be about three times greater to be consistent with keeping global temperature increase to well below 2 °C, and even seven times greater for 1.5 °C. Under the Paris Agreement, countries agreed to periodically update their Nationally Determined Contributions (NDCs) to climate change mitigation efforts. Countries were expected to formulate and submit their updated NDCs and long-term development strategies well in advance of COP26 in 2021. By the end of January 2022, 156 countries (including 27 EU Member States) have updated their NDC submissions.
In this publication, we synthesise their collective impact and discuss emissions reductions and implications at a global and national levels.
Projected global GHG emission levels by 2030
Global emissions are projected to peak by 2025, and reach about 3% above 2015 levels by 2030 if the unconditional NDCs are implemented, and return to 2015 levels if the conditional NDCs are implemented (see Fig. 2). This corresponds to about 11% and 7% above 2010 levels. This is well below the growth projected in the current policies scenario (11%).
The projected global emission level in 2030 is about 52.3 (50.1–54.1) GtCO2eq if all unconditional NDCs are implemented, and 50.7 (48.5–52.2) GtCO2eq if the conditional NDCs are implemented. The global GHG emissions of the conditional and unconditional updated NDC scenario are about − 4.4 and − 4.2 GtCO2eq by 2030, respectively, compared to the previous NDCs scenario. This effect is higher than the additional reduction due to the updated NDCs alone due to the lower emission projections from countries that overachieve their NDC targets.
Fig 1: The contribution of the updated NDC targets of countries on total additional global emission reduction (as indicated in blue column) based on the full implementation of the unconditional NDC targets (upper figure) and conditional NDC targets (lower figure), compared to the previous NDCs.
Impact of new NDCs on global emissions compared with previous NDCs
The full implementation of all unconditional updated NDC targets is estimated to have an aggregated reduction impact on global GHG emissions of about 3.8 (2.1–4.5) GtCO2eq by 2030, compared to that of the previous NDCs (Fig. 1). If the conditional updated NDCs are also fully implemented, the total reduction impact would be 3.9 (2.4–4.5) GtCO2eq, so about 0.1 GtCO2eq higher.
Fig 2: Impact of the implementation of the NDCs and current policies on greenhouse gas emission projections and on narrowing the emission gap in 2030