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

Short introduction on Bosnia & Herzegovina’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 28.4 mega tonnes of CO₂ (Mt CO₂eq), Bosnia & Herzegovina contributed 0.059% to the global greenhouse gas emissions of 2017 (rank 108 - 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, Bosnia & Herzegovina’s global contribution to greenhouse gas emissions is projected to stay at a similar level of approximately 0.060% (33.7 mega tonnes of CO₂ equivalent / rank 112 - incl. EU27 on rank 4). The emissions projections for Bosnia & Herzegovina 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, Bosnia & Herzegovina represented 0.044% of the global population. Its Gross Domestic Product (GDP) in 2017 were 0.038% 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 IPPU (73.9% and 12.3%). Amongst the greenhouse gases that are considered in the Kyoto Protocol, the strongest contributor with 78.2% was CO₂. This was followed by CH₄ emissions, with a significantly lower share of 10.7%. When not considering the sectors and gases independently, but the sector-gas combinations instead, Energy CO₂ and IPPU CO₂ (70.7% and 7.4%) 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, Bosnia and Herzegovina communicates that “according to the baseline scenario (BAU) in 2030 expected emissions are 20% higher than the level of emissions in 1990. Emission reduction that BiH unconditionally might achieved, compared to the BAU scenario, is 2% by 2030 which would mean 18% higher emissions compared to the base year 1990. Significant emission reduction is only possible to achieve with international support, which would result in emission reduction of 3% compared to 1990, while compared to the BAU scenario it represents a possible reduction of 23%.” (NDC, p. 2).

1990 base year emissions are 34.043 MtCO₂eq without LUCF, and 26.61996 MtCO₂eq with LUCF NDC, p. 2). The GWP is not given in the NDC, but could be assumed to be SAR, as the country references to “The Revised IPCC Guidelines for National Greenhouse Gas Inventories of 1996” (NDC, p. 2). BAU emissions are not directly provided, but based on the above given information, we calculate the 2030 BAU emissions to reach 40.852 MtCO₂eq (without LUCF), or 34.382 MtCO₂eq (with LUCF). Bosnia and Herzegovina notes that “total emissions also have an upward trend. According to the developed scenarios - their peak occurs in 2030” (NDC, p. 2), and based on the given relative reductions and BAU emissions, we calculate the 2030 target emissions as 32.748 MtCO₂eq in the unconditional, and 25.599 MtCO₂eq in the 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.

Bosnia and Herzegovina indicates that “All the values (total emission) provided in the baseline, as well as in the given projections, are calculated without the absorption potential (emission sink) of forestry sector. Although the forestry sector is not included in the presented balance of emissions, it is important to note that the value of sequestration capacity is app. 6.470 GgCO₂ in 2015 (1990 sinks - 7,423 GgCO₂), and that the emission projections intend to keep it on that level.” (NDC, p. 5).

The country’s contribution is “economy-wide”, and all main IPCC emissions sectors (Energy, IPPU, Agriculture, LULUCF, and Waste) are explicitly stated as covered (NDC, p. 1). From the Kyoto GHGs, CO₂, CH₄, and N₂O are listed as covered (NDC, p. 1), why we expect the F-gases not to be covered. In total, our assessment of covered sectors and gases results in an estimated 95.1% of 2017’ emissions being targeted by the NDC (based on PRIMAP-hist v2.1 HISTCR exclLU, in AR4).

The NDC-assessment is based on Bosnia & Herzegovina’s NDC submitted to the UNFCCC in March 2017.

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

---

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).

---

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?).