Historical emissions data for 1990–2021 are taken from the April 2023 update of Switzerland’s GHG inventory (Swiss Confederation, 2023).
To estimate historic emissions in 2021, we used the IMF GDP growth rate to approximate the impact on energy and industry emissions (IMF, 2022). We assumed that agriculture and waste sector emissions follow the five-year trend.
NDC and other targets
We calculated the 2030 targets using the most recent national inventory (Swiss Confederation, 2023).
Switzerland has not officially communicated the domestic share of its NDC target and has removed any specific information from the current version of the CO2 Reduction Act. In a previous draft from 2021 it stated that 33% of emissions will be reduced domestically (by 2030 below 1990 levels). From other official communication documents it becomes evident, that there is a consensus that at least 30% will be reduced within the borders. Due to a lack of clear information we have therefore decided to take a range between 30% and 33% by 2030 below 1990 levels as our domestic share.
Switzerland’s NDC includes LULUCF. The NDC states the desire to use a reference level for forest land, while emissions for other land uses will be included both in the target and baseline years. To assess LULUCF emissions in 2030, we take an average between the two projections WEM (with existing measures) and WAM (with additional measures) as to reach the 2030 target the emissions reduction pathway would need to be in between the two scenarios.. Since there is some uncertainty on both the accounted LULUCF emissions and the target itself, we show the target as a range, with the lower end of the range representing emission levels of 33% reductions without the accounted LULUCF emissions.
Current policy projections
We use the “with existing measures” scenario submitted to the UNFCCC in Switzerland’s 5th Biennial Update Report for our current policy projections (Swiss Federal Office for the Environment, 2022). The scenario reflects the current state of legislation. To get a range of the emissions projections pathways, we also include emissions projections from the European Environmental agency (EEA) which are based on the same “with existing measures” scenario but harmonised slightly differently (European Environment Agency, 2023). This projection is harmonised to actual 2021 emissions from the most recent national inventory (Swiss Confederation, 2023).
Planned policy projections
The planned policy projections scenario is based on the “with additional measures” scenario of the fifth biennial report (Swiss Federal Office for the Environment, 2022). It includes a number of measures and instruments that are under discussion for the amended third CO2 Succession Act for the period 2025–2030, which is in consultation. To get a range of the emissions projections pathways, we also include emissions projections from the European Environmental agency (EEA) which are based on the same “with additional measures” scenario but harmonised slightly differently (European Environment Agency, 2023).
Net-zero target and other long-term targets
In its LTS, the Swiss government provides assumptions on their estimated residual emissions to meet its 2050 net-zero GHG target. The pathway shows that 11.8 MtCO2 of residual emissions in 2050 will be met by carbon capture and storage (CCS) and negative emissions technologies (NET) in Switzerland and abroad. We assumed a linear decline in total GHGs between emission levels in 2030 and residual emissions levels in 2050.
Global Warming Potentials values
The CAT uses Global Warming Potential (GWP) values from the IPCC’s Fourth Assessment Report (AR4) for all figures and time series. Assessments completed prior to December 2018 (COP24) used GWP values from the IPCC’s Second Assessment Report (SAR).