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

Short introduction on Brazil’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 1.1 giga tonnes of CO₂ (Gt CO₂eq), Brazil contributed 2.34% to the global greenhouse gas emissions of 2017 (rank 7 - 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, Brazil’s global contribution to greenhouse gas emissions is projected to increase to approximately 2.63% (1.5 giga tonnes of CO₂ equivalent / rank 6 - incl. EU27 on rank 4). The emissions projections for Brazil 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, Brazil represented 2.75% of the global population. Its Gross Domestic Product (GDP) in 2017 were 2.61% 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 Agriculture and Energy (44.8% and 39.0%). Amongst the greenhouse gases that are considered in the Kyoto Protocol, the strongest contributor with 45.5% was CO₂. This was followed by CH₄ emissions, with a share of 36.9%. When not considering the sectors and gases independently, but the sector-gas combinations instead, Energy CO₂ and Agriculture CH₄ (36.1% and 28.5%) 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 updated NDC, “Brazil confirms the commitment originally presented in its intended Nationally Determined Contribution (iNDC), to reduce its greenhouse gas emissions in 2025 by 37%, compared with 2005. Additionally, Brazil commits to reduce its emissions in 2030 by 43%, compared with 2005.” (NDC, p. 1). Even though not stated explicitly, we assume Brazil’s contribution to be unconditional on, e.g., international financial support or technology transfer.

The sectors that are covered by Brazil’s GHG mitigation target are not explicitly stated, but the country declares the target to be economy-wide (NDC, p. 3), and “consistent with the sectors present in the National Inventory of Greenhouse Gas Emissions for 2025 and 2030, always compared with 2005”. The provided reference level are total net emissions, and LULUCF contributions are included in the target (NDC, p. 2). Based on the given information, the covered sectors are assessed to be all main IPCC sectors (Energy, IPPU, Agriculture, LULUCF, and Waste). Furthermore, the targeted gases are given as CO₂, CH₄, N₂O, SF₆, PFCs, and HFCs (NDC, p. 3), while NF₃ is not mentioned. For NF₃, e.g., PRIMAP-hist v2.1 has no historical emissions data available for Brazil. NF₃ has only been added to the Kyoto GHG basket for the Kyoto Protocol’s second period. It is merely reported by few countries and contributed less than 0.01% to global Kyoto GHG emissions in 2017 (exclLU and exclBF, based on PRIMAP-hist v2.1 HISTCR, in AR4, with its share being influenced by the few available data).

The NDC does not contain the base year emissions, but references to Brazil’s “Third National Communication from Brazil to the United Nations Framework Convention on Climate Change”, submitted on 20 April 2016” (emissions available on p. 40). It shows that the national net GHG emissions in the chosen base year (2005) were high in comparison to the also provided emissions for the years 2000 and 2010. This results in higher absolute target emissions, compared to a potential target referencing to 2000 or 2010 emissions levels (2000: 2.1 GgCO₂eq AR5, 2005: 2.8 GgCO₂eq AR5, 2010: 1.4 GgCO₂eq AR5, all emissions including LULUCF). 2005 emissions excluding LULUCF are 0.9 GgCO₂eq AR5 (LULUCF: 1.9 GgCO₂eq AR5). From the given quantitative information, the absolute target emissions for 2025/2030 are estimated as 1.8/1.6 GgCO₂eq AR5 including LULUCF (excluding LULUCF and assuming the same relative reductions of 37/43%: 0.6/0.5 GgCO₂eq AR5). 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. Besides Brazil’s 2030 target no longer being an incentive target, but rather a commitment, the updated 2020 NDC is no improvement compared to the 2016 submission in terms of absolute target emissions, as the relative reductions stayed the same, but the reference emissions for the year 2005 increased, resulting in higher target year emissions.

Regarding the Article 6 of the PA (cooperation and markets), the NDC indicates that it intends to use voluntary cooperation, when appropriate (NDC, p. 6: “Any transfer of units from mitigation results obtained in the Brazilian territory within the framework of the UNFCCC, the Kyoto Protocol or the Paris Agreement will be contingent on prior and formal consent by the Brazilian Federal Government.”).

The NDC also mentions a long-term vision, with “Brazil’s Nationally Determined Contribution is compatible with an indicative longterm objective of reaching climate neutrality in 2060. The final determination of any long-term strategy for the country, in particular the year in which climate neutrality may be achieved, will, however, depend on the proper functioning of the market mechanisms provided for in the Paris Agreement. The possibility of adopting a more ambitious long-term objective at the appropriate time is not ruled out.” (NDC, p. 3). In the document we found inconsistencies, as both climate and carbon neutrality by 2060 are mentioned.

The NDC-assessment is based on Brazil’s NDC submitted to the UNFCCC in December 2020.

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

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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?).