The Paris Agreement and NDCs: are the national mitigation targets sufficient to stay below the 1.5-2°C limit?

Short introduction on Ghana’s emissions

Although CO₂ is the driving force behind the temperature changes, other gases such as methane (CH₄) also contribute their share to global warming, for example through the exploitation of gas fields, and emissions by livestock. While methane is emitted much less than CO₂ on a global scale, it is a much stronger greenhouse gas (GHG). Scientists estimated the relative strength of the important Kyoto greenhouse gases so that we can convert all emissions to an equivalent of CO₂ emissions. For example, the emission of one ton of methane has approximately the warming effect of 25 tons of CO₂. The factor of 25 reflects the climate forcing on a 100-year time horizon, following the Global Warming Potential presented in the IPCC Fourth Assessment Report (AR4).

With greenhouse gas emissions of approximately the equivalent of 32.9 mega tonnes of CO₂ (Mt CO₂eq), Ghana contributed 0.068% to the global greenhouse gas emissions of 2017 (rank 105 - incl. EU27 on rank 3). All emissions estimates exclude emissions and absorption from land, which result from activities such as cutting down or planting of forests (Land Use, Land-Use Change and Forestry: LULUCF). Emissions from bunker fuels (international aviation and shipping) were also excluded, as they are not accounted for in national totals.

For 2030, Ghana’s global contribution to greenhouse gas emissions is projected to stay at a similar level of approximately 0.097% (54.6 mega tonnes of CO₂ equivalent / rank 94 - incl. EU27 on rank 4). The emissions projections for Ghana were derived by downscaling the Shared Socio-Economic Pathways’ (SSPs) “Middle-of-the-Road” baseline marker scenario SSP2. These pathways describe certain narratives of socio-economic developments and were, i.a., used to derive greenhouse gas emissions scenarios that correspond to these developments. SSP2 is a narrative with little shifts in socio-economic patterns compared to historical ones, and is connected to medium socio-economic challenges for both climate mitigation and adaptation. While different models were used for each storyline, per SSP (SSPs1-5) one model was chosen as representative “marker scenario”. As the emissions projections are not readily available on country-level, but national estimates are important, the pathways were downscaled in the aftermath. In 2017, Ghana represented 0.38% of the global population. Its Gross Domestic Product (GDP) in 2017 were 0.13% of the global GDP.

Looking at the highest contributing emissions sectors and gases separately, we find that in 2017 the highest contributing emissions sectors were Energy and Agriculture (58.9% and 26.2%). Amongst the greenhouse gases that are considered in the Kyoto Protocol, the strongest contributor with 44.2% was CH₄. This was followed by CO₂ emissions, with a share of 40.5%. When not considering the sectors and gases independently, but the sector-gas combinations instead, Energy CO₂ and Energy CH₄ (38.4% and 19.5%) represented the largest emissions in 2017.

Greenhouse gas mitigation and Nationally Determined Contribution (NDC)

In 2015, the majority of countries agreed to the Paris Agreement (PA), with the goal of “Holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change” (Article 2.1.a). Countries stated their pledges and targets towards achieving the PA’s goals in their Nationally Determined Contributions (NDCs). With Article 4.4 of the Paris Agreement, Parties decided that “Developed country Parties should continue taking the lead by undertaking economy-wide absolute emission reduction targets. Developing country Parties should continue enhancing their mitigation efforts, and are encouraged to move over time towards economy-wide emission reduction or limitation targets in the light of different national circumstances.”

In its NDC, Ghana communicates that “Under the unconditional emission reduction goal, emissions are expected to decrease by 12 percent and 15 percent relative to the BAU emission levels in 2025 and 2030 respectively. A similar emission trajectory is anticipated under the ‘conditional emission reduction goal’ except that the degree of deviation relative to the BAU emission is higher compared to the projections under the unconditional goal. Under the ‘conditional emission reduction goal’, emission are expected to decrease by 27 percent and 45 percent relative to the BAU emissions in 2025 and 2030 respectively.” (NDC, p. 4). Furthermore, the country indicates that the “additional 30 percent emission reduction is attainable on condition that external support is made available to Ghana to cover the full cost of implementing the mitigation action (finance, technology transfer, capacity building).” (NDC, p. 4).

Under BAU, with the reference year 2010 (NDC, p. 5), emissions are expected to rise to 73.95 MtCO₂eq SAR in 2030 (NDC, p. 4, GWP: p. 5). From the BAU emissions, we calculate the absolute target emissions to amount to 47.08 and 62.86 MtCO₂eq SAR (-12 and -15%) in 2025 and 2030, respectively, in the unconditional case, and to 39.05 and 40.67 MtCO₂eq SAR (-27 and -45%) in 2025 and 2030, respectively, in the more ambitious conditional case. The availability of national estimates of emissions mitigation targets and pathways in line with countries’ NDCs is of great importance when, e.g., aggregating to global emissions to then derive, i.a., the resulting end-of-century warming levels.

In terms of coverage, the scale is “economy-wide”, and all main IPCC emissions sectors are explicitly listed as covered (“energy including transport, industrial process and product use, AFOLU and waste.”, NDC, p. 5). The covered “Basket of gases [is] Carbon dioxide (CO₂), Methane (CH₄), and Nitrous Oxide (N₂O)”, and the “Abatement of fluorinated-gases (HFC-22 and HFC-410) from stationery air-conditioners is included.” (NDC, p. 5). Following Ghana’s NDC, “100% of total national GHG emissions” are covered (NDC, p. 5), which is in line with our assessment, based on PRIMAP-hist v2.1 HISTCR exclLU. For PFCs, the dataset shows 0 MtCO₂eq emissions for Ghana in 2017, while for SF₆ and NF₃, no data are available for the country.

Amongst the mitigation measures, Ghana includes a LULUCF component, planning sustainable forest management (NDC, p. 3+4). To “Promote Sustainable utilization of forest resources through REDD+”, the country will “Continue 10,000ha annual reforestation/afforestation of degraded lands” (unconditional), and “Double 10,000ha annual reforestation/afforestation of degraded lands translating to 20,000ha on annual basis” (conditional). (NDC, p. 14). Additionally, as conditional mitigation contributions, Ghana intends to “Support enhancement of forest carbon stocks through 5,000ha per annum enrichment planting and enforcement of timber felling standards; 45% (Provisional targets. Forest reference level is limited to avoided deforestation. New estimates will be submitted before 2020.) emission reduction through result-based emission reduction programme in cocoa landscape; Wildfire management in the transition and savannah dry lands in Ghana” (NDC, p. 14).

The NDC-assessment is based on Ghana’s NDC submitted to the UNFCCC in September 2016.

The Figure below provides additional information, regarding both the baseline emissions used in our assessment and the quantified mitigated pathways for Ghana.

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Baseline emissions and mitigated emissions pathways based on the country’s Nationally Determined Contribution. In terms of national emissions, we look at the SSP2 baseline marker scenario, and the emissions of all IPCC sectors. Contributions from LULUCF are excluded (exclLU), and the emissions are based on GWPs from AR4. The left panel (a) shows the baseline emissions, indicating the contributions of the Kyoto Greenhouse Gases CO₂, CH₄, N₂O, and the basket of F-gases to the national emissions. If we could extract baseline data exclLU from the NDC, you can see their values as black squares (converted from GWP SAR to AR4 if needed). In the right panel (b), the quantified mitigated emissions pathways are shown, based on information from the country’s NDC and also on non-NDC emissions baselines, per target conditionality and range (marked un-/conditional best/worst). Even though not all countries have targets with different conditionalities or ranges, we need assumptions for all four cases to build one global pathway per conditionality plus range combination and to derive corresponding temperature estimates. Therefore, we indicate these four pathways here. Per combination, we performed several quantifications with differing assumptions and show the median and the minimal and maximal pathways here. Additionally, if we could quantify the targets based on data extracted purely from the NDC - or if the targets were directly given in absolute emissions, these targets are shown as squares (in the GWP originally given in the NDC).

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FIG 1

Data sources and further information

• Historical emissions: PRIMAP-hist v2.1 (Guetschow et al., 2016, 2019).
• Historical socio-economic data: PRIMAP-hist Socio-Eco v2.1 (Guetschow et al., 2019).
• Projected emissions and socio-economic data: downscaled SSPs (Guetschow et al., 2020, 2020).
• NDC quantifications: NDCmitiQ (Guenther et al., 2020, 2021).
• GDP is given in purchasing power parity (PPP).
• Main emissions sectors (Intergovernmental Panel on Climate Change, IPCC): Energy, Industrial Processes and Product Use (IPPU), Agriculture and LULUCF (Land Use, Land-Use Change and Forestry), also named AFOLU (Agriculture, Forestry and Other Land Use), and Waste.
• Kyoto GHG: basket of several GHGs, namely carbon dioxide (CO₂), Methane (CH₄), nitrous oxide (N₂O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF₆), and since the second Kyoto Protocol period (2013-20) additionally nitrogen fluoride (NF₃).
• Global Warming Potentials (GWPs): GHGs have very different warming potentials. To make them comparable and for aggregation purposes, GWPs are used (how much energy will 1 ton of a certain gas absorb over a defined period of time, relative to the same mass of CO₂?).