Historical emissions for the years 1990, 1996, 2000 and 2005 were taken from the latest UNFCCC inventory (UNFCCC, 2019) and converted to AR4 based on a yearly AR4/SAR factor for Costa Rica estimated with gas by gas data from Gieseke & Gütschow (2018). For 2012, we used data from the Third National Communication (Ministerio de Ambiente y Energía, 2014) and the 1st Biennial Update Report (BUR) (Ministerio de Ambiente y Energía, 2015a). Historical emissions for 2015 are extracted from the 2nd BUR (Ministerio de Ambiente y Energía, 2019). Historical data from the BURs were converted from SAR to AR4 using the gas split provided in the respective documents and the appropriate GWPs. We interpolated for the years in between. In its Third National Communication, 1st and 2nd Biennial Update Reports, Costa Rica reported its emissions following the IPCC 2006 guidelines, meaning that emissions from Land Use and Forestry are reported as part of the AFOLU (Agriculture, Forestry, and Land Use) category. The CAT analysis excludes LULUCF emissions. We therefore estimated LULUCF emissions for 2010, 2012 and 2015 by recalculating the values from the detailed AFOLU sectoral emissions. Updated values for emissions in 2005 and 2010 were provided in the 1st BUR, but because there are no details on the AFOLU sector, we could not use these updated figures.
NDC and other targets
Costa Rica’s NDC states a target to be carbon neutral by 2085 and pledges to keep emissions below 9.4 MtCO2e by 2030, including LULUCF. It is unclear whether the National Decarbonisation Plan 2018–2050—announced in February 2019—will replace or only guide the next NDC pledge. As of June 2020, no updated NDC has been submitted to the UNFCCC. Given this unclarity we have not yet excluded the NDC long-term target from our assessment. The National Decarbonisation plan 2018–2050 presents a pathway to achieve net-zero emissions by 2050 (Gobierno de Costa Rica, 2019b).
Costa Rica’s NDC expresses its 2030 target both as absolute emissions limit and as a ‘25% reduction from 2012 levels’—which according to our estimates is lower than their absolute target. We have therefore estimated a range based on the two interpretations—the absolute number and the reduction percentage—using the figures communicated in Costa Rica’s NDC and the projections for LULUCF emissions from the 2nd Biennial Update Report (Ministerio de Ambiente y Energía, 2019). The CAT presents all targets excluding LULUCF and with global warming potentials (GWPs) from the IPCC’s fourth assessment report (AR4).
For the NDC’s 2050 targets we have assumed a range for LULUCF emissions. We assume the lower end of LULUCF emissions from 2015—the last historical available year from the 2nd BUR—and the higher end as LULUCF emissions from 2050—the last available year from the BUR WAM scenario. We assume these two different ends of the range as there is uncertainty about LULUCF emissions. Efforts—including a REDD+ strategy—exist to reduce emissions in the LULUCF sector. Nevertheless, a national study (Sancho, Rivera and Obando, 2015), which estimates emissions from LULUCF by examining the forest compositions and historical trends, projects that the LULUCF sinks will start to shrink after 2029 and emissions from this sector will become positive in 2050.
Current policy projections
The upper range of our current policy projections is based on the Conservative baseline scenario from the 1st Biennial Update Report (BUR) (Ministerio de Ambiente y Energía, 2015a) and national estimates of Law 9518 from 2018 on transport electrification (Gobierno de Costa Rica, MINAE and MOPT, 2019). The Conservative baseline scenario from the 1st BUR includes only actions or projects at a sector or economy wide level that are already implemented or which have received a first investment that makes them irreversible (Ministerio de Ambiente y Energía, 2015a). The 2nd BUR presents two scenarios: A BAU and the WAM scenario. The BAU scenario leads to emissions at the same level as the Conservative baseline scenario in the 1st BUR. The WAM scenario is based on current mitigation measures as well as ‘realistic’ mitigation options proposed by individual sectors which are not yet implemented (Ministerio de Ambiente y Energía, 2019). It was not possible to extract a scenario using only current implemented measures, excluding additional ‘realistic’ measures. We have included the WAM scenario as the lower range of Costa Rica’s current policy scenario and the Decarbonisation Plan 2018–2050 (Gobierno de Costa Rica, 2019b), which leads to lower emissions, as the planned policy scenario.
Planned policy projections
We have included a planned policy pathway, which is line with the 1.5° pathway of Costa Rica’s Decarbonisation Plan 2018–2050 (Gobierno de Costa Rica, 2019b). Since the pathway starts only in 2018 and given that inventory data is only available until 2015, we have harmonised to current policy projections between the two dates. We have added a range for planned policy projections until 2030. The upper end of the range is a pathway assuming implementation of policies for the energy sector only, whereas the lower end of the range assumes implementation of policies from the energy, industry, agriculture and waste sectors.
We applied a novel method to estimate the COVID-19 related dip in greenhouse gas emissions in 2020 and the deployment through to 2030. The uncertainty surrounding the severity and length of the pandemic creates a new level of uncertainty for current and future greenhouse gas emissions. We first update the current policy projections using most recent projections, usually prepared before the pandemic. We then distil the emission intensity (GHG emissions/GDP) from this pre-pandemic scenario and apply to it most recent GDP projections that take into account the effect of the pandemic. We have used a range of estimates from both national and international sources to estimate the potential impact of the pandemic on GDP (Instituto de Investigaciones en Ciencia Economicas, 2020; International Monetary Fund, 2020; Pimentel, 2020). The national and international estimates only cover 2020 and 2021. We used the growth rates from our pre-COVID-19 current policy scenario to extend those projections to 2030.Planned policy projections.
Global Warming Potential values
The CAT uses Global Warming Potential (GWP) values from the IPCC's Fourth Assessment Report (AR4) for all its figures and time series. Assessments completed prior to December 2018 (COP24) used GWP values from the Second Assessment Report (SAR).