Historical emissions for the period 1990-2021 are from PRIMAPhist dataset (for CO2, CH4, N2O and F-gases) (Gütschow et al., 2022).
Singapore is a city-state with one of the highest population densities in the world and is nearly completely dependent on imports for food. Most of the remaining natural areas are sanctuaries. We therefore do not consider emissions related to LULUCF sector for the analysis, as they are negligible.
NDC and other targets
Singapore’s updated NDC provides an absolute emissions level (60 MtCO2e) for 2030 in AR5 GWP (Singapore Government, 2022). We do not convert the AR5 GWP to AR4 GWP (60 MtCO2e) as no gas by gas break up is provided in the NDC and also in 2021 93% of Singapore’s emissions is comprised of CO2, hence the conversion from AR5 to AR4 will not lead to any significant change in the absolute emissions reduction.
Net zero target
To quantify Singapore’s 2050 emissions we assume that Singapore will be able to maintain its average historical LULUCF emissions until 2050 using the latest government inventory data (National Environment Agency, 2018, 2020). We estimates the average LULUCF emissions by taking inventory data for the year 2010, 2012, 2014 and 2016 and take that as the residual emissions in 2050 as the country has set to achieve net zero by 2050.
Current policy projections
Our current policy emissions pathway relies on energy, fuel type and sectoral projections for CO2 emissions projections of the 8th edition of the energy outlook of the Asia Pacific Energy Research Centre (APEC, 2022). For other-CO2 and non-CO2 projections, we assume that the average of pre-COVID 5 year (2015-2019) growth rate will continue until 2030.
Given that both sources present differences with historical values, we harmonise with historical values by applying growth rates from the projections to the last reported year (2021).
We excluded emissions from marine and aviation bunkers when calculating the comparability range which determines the rating. These emissions are nearly three times higher than the rest of Singapore's emissions—with the great majority being related to Singapore’s role as a hub in international shipping.
Global warming potentials
The CAT uses Global Warming Potential (GWP) values from the IPCC’s Fourth Assessment Report (AR4) for all figures and time series. Assessment completed prior to December 2018 (COP24) used GWP values from the IPCC’s Second Assessment Report (SAR).