Annex

Annex Background note – Quantification of climate action plans

The data used for the quantification of climate action plans are retrieved from national plans submitted by countries to the United Nations Framework Convention on Climate Change. In the event that the data are found to be sparse or insufficient, they are supplemented with data from the PRIMAP database, which combines several published datasets to create a comprehensive set of greenhouse gas emission pathways for each country. All Nationally Determined Contributions (NDCs) and long-term strategies or net zero targets communicated by parties as of November 12, 2021, are included in the COP26 announcements scenario. The COP26 announcements scenario is based on an “optimistic” climate analysis that assesses the lowest emission level of the full NDC implementation, i.e. including both conditional and unconditional contributions.

The dataset collected from “Climate Resource” was chosen because of its quality, transparency and comprehensiveness. It has been produced from an extensive quantification of NDCs, as well as the most recent long-term strategies and announced climate pledges. Where countries do not communicate whole-economy targets, the reference level emissions are assumed for that sector. In that case, the reference level emissions changes are sourced from the SSP5 reference, downscaled to a country-by-country emission level. For each submitted NDC, future emissions levels are quantified for 2025, 2030 and 2050. In cases where countries submit only for 2025 or beyond 2030, linear interpolations and extrapolations are applied to derive the 2030 emission level. It is assumed that NDC target levels that are higher than high reference scenarios (i.e. scenarios without additional climate or energy policies to reduce emissions) are not going to be reached, but “overachieved”. For countries where this is the case (like Turkey or Pakistan), it is assumed that the country-downscaled and high-emission growth SSP5 reference scenarios, normalised with recent historical emissions, portray the maximum amount of emissions. For countries without longer-term targets, the SSP1 reference growth rates for the period 2030-2050 are assumed based on a quantile rolling window approach by Lamboll et al. (Lamboll et al., 2020).

The IRENA WETO Planned Energy Scenario (PES) considers national plans and policies prior to the NDC updates for COP26. In this regard, the difference between the PES curve and the COP26 announcements curve is due to countries’ increased climate ambition in the run-up to COP26. The area difference between the plotted WETO 1.5°C Scenario and the COP26 announcements scenario represents the additional effort required to meet WETO’s 1.5°C target. To stay within the 1.5°C target, emissions in 2030 would need to be around 22.2 GtCO2, down from 37.5 GtCO2 under the COP26 announcement scenario.

Concerning gas coverage, the greenhouse gas (GHG) emissions included in the COP26 announcements scenario have been converted to global CO2 emissions trajectories to be consistent with the WETO 1.5°C Scenario. To estimate CO2 emissions in the COP26 announcements scenario, the ratio of CO2 emissions (excluding that of the agriculture, forestry and other land use [AFOLU] sector) in IPCC scenario SSP1-2.6 to total GHG emissions (including AFOLU) in scenario SSP1-2.6 using GWP100 from AR5, has been applied. CO2 emissions from AFOLU have been estimated in the COP26 announcements scenario using CO2 emissions data from the same IPCC scenario (SSP1-2.6).

The same methodology is applied to quantify the CO2 emissions from G20 members in comparison to global CO2 emission levels. Climate Resource datasets were also used to obtain the most recent GHG emissions (excluding AFOLU) from the G20 members' latest national plans and climate pledges. The G20 GHG emissions have been converted to CO2 emissions using the same ratio applied to the global COP26 announcements scenario. G20 CO2 emissions (excluding AFOLU) are then compared with global CO2 emissions (excluding AFOLU) to determine to what extent G20 members contribute to the global share of CO2 emissions.

Other organisations, such as the World Resources Institute, the International Energy Agency and Climate Analytics, provide datasets that can be used to quantify climate pledges to GHG emission reductions. As these datasets are based on different assumptions and methodologies, as well as different coverage of greenhouse gases and sectors, the results will naturally vary. However, the projected emissions trajectories generated by all of the aforementioned datasets remain consistent, i.e. a nearly flat line or a minor deviation, reflecting no noticeable decrease in emissions between 2020 and 2030. Following 2030, a sharper decrease in CO2 emissions is projected, reflecting the long-term strategies and net zero GHG targets beyond 2030 communicated by countries.

Lamboll, R.D. et al. (2020), “Silicone v1.0.0: An open-source Python package for inferring missing emissions data for climate change research”, Geosci. Model Dev. vol. 13, pp. 5259–5275.

ISBN: 978-92-9260-429-5