Editing IPCC:AR6/WGIII/Chapter-4 (section)

=== 4.2.1 Mitigation Targets and Measures in Nationally Determined Contributions ===

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A central instrument of the Paris Agreement is the NDCs, submitted by each country, and reflecting national efforts to reduce GHG emissions and build resilience to the impacts of climate change. Every five years, collective progress will be compared against long-term goals of the Paris Agreement. Considering the outcome of a global stocktake, countries will prepare subsequent NDCs, showing progression in their ambition and enhancing international cooperation ( [[#UNFCCC--2015a|UNFCCC 2015a]] ).

Prior to COP21, in 2015, most countries submitted their Intended Nationally Determined Contributions (INDCs), which included mitigation targets for 2025 or 2030. INDCs become first NDCs on ratification and/or after national governments’ revision, and by 11 October 2021, the official NDC registry contained 194 first NDCs with 105 new and updated NDCs from 132 Parties to the Paris Agreement, covering 53% of the total global emissions in 2019 of 52.4 GtCO 2 -eq without land use, land-use change and forestry (LULUCF), and 13 second NDCs. Most of the Parties that submitted new or updated NDCs have demonstrated increased ambition in addressing climate change. Moreover, though some countries have not submitted their updated NDCs yet, they have already announced their updated NDC goals somewhere. Countries will take the first stock in 2023 based on their progression towards achieving the objectives of Paris Agreement ( [[#UNFCCC--2015a|UNFCCC 2015a]] , 2018a; [[#SB%20Chairs--2021|SB Chairs 2021]] ) ( [[IPCC:Wg3:Chapter:Chapter-14#14.3.2.5|Section 14.3.2.5]] ).

Submitted NDCs vary in content, scope and background assumptions. First NDCs contain mitigation targets, and in many cases also provisions about adaptation. The mitigation targets range from economy-wide absolute emission reduction targets to strategies, plans and actions for low-emission development. Baseline years vary from 1990 to 2015 and in almost all NDCs the targeted time frame is 2030, with a few specified periods of until 2025, 2035, 2040 or 2050. Around 43% of the mitigation targets in first NDCs are expressed in terms of deviation below business-as-usual by a specified target year, either for the whole economy or for specific sectors, while around 35% include fixed-level targets (either reductions or limitations compared to base years), and another 22% refer to intensity targets (in terms of GHG, CO 2 or energy) or policies and measures, with an increasing number of Parties moving to absolute emission reduction targets in their new or updated NDCs ( [[#UNFCCC--2016a|UNFCCC 2016a]] , 2021). Some developing countries’ NDCs include unconditional elements, while others include conditional ones, the latter with higher ambition if finance, technology and capacity building support from developed countries is provided ( [[#UNFCCC--2016a|UNFCCC 2016a]] ). [[#footnote-004|2]] In some NDCs, the additional mitigation is quantified, in others not (Figure 14.2).

Most first NDCs cover all specific sectors, including LULUCF, and communicate specific targets for individual sub-sectors to support their overall mitigation targets. Concrete actions and priority areas are more detailed in the energy sector, with increased share of renewable energies and energy efficiency being highlighted in the majority of NDCs. Given the uncertainty behind LULUCF emission and removal accounting ( [[#Grassi--2017|Grassi et al. 2017]] ; Jian et al. 2019), several countries state that their accounting framework will only be defined in later NDCs. The GHG included and the global warming potentials (GWPs) used to aggregate emissions also vary across NDCs. Most countries only refer to carbon dioxide, methane and nitrous oxide emissions aggregated based on IPCC AR2 or AR4 metrics, while few NDCs also include [https://www.epa.gov/ghgemissions/overview-greenhouse-gases#f-gases fluorinated gases] and use IPCC AR5 GWPs. The shares of Parties that indicate possible use of at least one type of voluntary cooperation and set qualitative limits on their use have both nearly doubled in new or updated NDCs.

There is considerable literature on country-level mitigation pathways, including but not limited to NDCs. Country distribution of this literature is very unequal ( ''robust evidence'' , ''high agreement'' ). In particular, there is a growing literature on (I)NDCs, with a wide scope which includes estimate of emissions levels of NDCs (Section 4.2.2.2); alignment with sustainable development goals ( [[#Caetano--2020|Caetano et al. 2020]] ; [[#Campagnolo--2019|Campagnolo and Davide 2019]] ; [[#Fuso%20Nerini--2019|Fuso Nerini et al. 2019]] ; Antwi-Agyei et al. 2018); ambition ( [[#Höhne--2018|Höhne et al. 2018]] ; [[#Vogt-Schilb--2017|Vogt-Schilb and Hallegatte 2017]] ; [[#Hermwille--2019|Hermwille et al. 2019]] ); energy development ( [[#Scott--2018|Scott et al. 2018]] ); and the legality of downgrading NDCs ( [[#Rajamani--2017|Rajamani and Brunnée 2017]] ). Other studies note that many NDCs contain single-year mitigation targets, and suggest that a multi-year trajectory is important for more rigorous monitoring ( [[#Elliott--2017|Elliott et al. 2017]] ; [[#Dagnet--2017|Dagnet et al. 2017]] ).

The literature also points out that beyond the ‘headline numbers’, information in (I)NDCs is difficult to analyse ( [[#Pauw--2018|Pauw et al. 2018]] ). Information for ‘clarity, transparency and understanding’ is to be communicated with NDCs, although initial guidance was not specific ( [[#UNFCCC--2014|UNFCCC 2014]] ). While the adoption of the Paris rule-book provided some greater specificity ( [[#UNFCCC--2018b|UNFCCC 2018b]] ,c), the information included in the NDCs remains uneven. Many NDCs omit important mitigation sectors and do not adequately provide details on costs and financing of implementation ( [[#Pauw--2018|Pauw et al. 2018]] ). Countries are also invited to explain how their NDCs are fair and ambitious, though the way this has been done so far has been criticised as insufficiently rigorous ( [[#Winkler--2018|Winkler et al. 2018]] ).

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