Editing IPCC:AR6/WGIII/Chapter-14 (section)

==== 14.3.3.2 Effectiveness of the Paris Agreement ====

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Given the comparatively recent conclusion of the Paris Agreement, evidence is still being gathered to assess its effectiveness in practice, in particular, since its long-term effectiveness hinges on states communicating more ambitious NDCs in successive cycles over time. Assessments of the Paris Agreement on paper are necessarily speculative and limited by the lack of credible counterfactuals. Despite these limitations, numerous assessments exist of the potential for international cooperation under the Paris Agreement to advance climate change mitigation.

These assessments are mixed and reflect uncertainty over the outcomes the Paris Agreement will achieve ( [[#Christoff--2016|Christoff 2016]] ; [[#Clémençon--2016|Clémençon 2016]] ; [[#Keohane--2016|Keohane and Oppenheimer 2016]] ; [[#Young--2016|Young 2016]] ; [[#Dimitrov--2019|Dimitrov et al. 2019]] ; [[#Raiser--2020|Raiser et al. 2020]] ). There is a divide between studies that do not expect a positive outcome from the Paris Agreement and those that do. The former base this assessment on factors such as: a lack of clarity in the expression of obligations and objectives; a lack of concrete plans collectively to achieve the temperature goal; extensive use of soft law (i.e., non-legally binding) provisions; limited incentives to avoid free-riding; and the Agreement’s weak enforcement provisions ( [[#Allan--2019|Allan 2019]] ), as well as US non-cooperation under the Trump administration and the resulting gap in mitigation, finance and governance ( [[#Bang--2016|Bang et al. 2016]] ; [[#Spash--2016|Spash 2016]] ; [[#Tulkens--2016|Tulkens 2016]] ; [[#Chai--2017|Chai et al. 2017]] ; [[#Lawrence--2017|Lawrence and Wong 2017]] ; [[#Thompson--2017|Thompson 2017]] ; [[#Barrett--2018|Barrett 2018]] ; [[#Kemp--2018|Kemp 2018]] ). Studies expecting a positive outcome emphasise factors such as: the breadth of participation enabled by self-differentiated NDCs; the ‘logic’ of domestic climate policies driving greater national ambition; the multiplicity of actors engaged by the Paris Agreement’s facilitative architecture; the falling cost of low-carbon technologies; provision for financial, technology and capacity-building support to developing country Parties; possibilities for voluntary cooperation on mitigation under Article 6; and the potential for progressive ratcheting up of Parties’ pledges over time fostered by transparency of reporting and international scrutiny of national justifications of the ‘fairness’ of contributions ( [[#Caparrós--2016|Caparrós 2016]] ; [[#Chan--2016a|Chan 2016a]] ; [[#Falkner--2016b|Falkner 2016b]] ; [[#Victor--2016|Victor 2016]] ; [[#Morgan--2017|Morgan and Northrop 2017]] ; [[#Urpelainen--2018|Urpelainen and Van de Graaf 2018]] ; [[#Hale--2020|Hale 2020]] ; [[#Tørstad--2020|Tørstad 2020]] ). Turning to the assessment criteria articulated in this chapter, the following preliminary assessments of the Paris Agreement can be made.

In relation to the criterion of ''environmental effectiveness'' , the Paris Agreement exceeds the Kyoto Protocol in terms of coverage of GHGs and participation of states in mitigation actions. In terms of coverage of GHGs, the Kyoto Protocol limits its coverage to a defined basket of gases identified in its Annex A (carbon dioxide (CO 2 ), methane (CH 4 ), nitrous oxide (N 2 O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF 6 ), as well as nitrogen trifluoride (NF 3 )). The Paris Agreement does not specify the coverage of gases, thus Parties may cover the full spectrum of GHGs in their NDCs as encouraged by the accounting provisions in Annex II to Decision 18/CMA.1 (or conversely they may choose to exclude important mitigation sectors) and there is also the possibility to include other pollutants such as short-lived climate forcers like black carbon. Article 4.4 calls on developed countries to undertake economy-wide emissions reduction targets with the expectation that developing country Parties will also move to introduce these over time. Moreover, the Paris Agreement makes express reference to Parties taking action to conserve and enhance ‘sinks and reservoirs of greenhouse gases’ (Article 5). As under the UNFCCC and Kyoto Protocol, this allows for coverage of land use, land-use change and forestry and agriculture, forestry and other land use (AFOLU) emissions, both CO 2 and other Kyoto Annex A gases, as well as methane ( [[#Pekkarinen--2020|Pekkarinen 2020]] ). A few countries, particularly LDCs, include quantified non-CO 2 emissions reductions from the agricultural sector in their NDCs, and many others include agriculture in their economy-wide targets ( [[#Richards--2018|Richards et al. 2018]] ). Some studies find that agricultural development pathways with mitigation co-benefits can deliver 21–40% of needed mitigation for the ‘well below 2°C’ limit, thus necessitating ‘transformative technical and policy options’ ( [[#Wollenberg--2016|Wollenberg et al. 2016]] ). Other studies indicate that broader ‘natural climate solutions, including forests, can provide 37% of the cost-effective CO 2 mitigation needed through 2030 for a more than 66% chance of holding warming to below 2°C’ ( [[#Griscom--2017|Griscom et al. 2017]] ).

As Figure 14.2 illustrates graphically, communicated unconditional NDCs, if achieved, lead to a reduction of about 7% of world emissions by 2030 in relation to the Kyoto GHGs, and NDCs with conditional elements increase this reduction to about 12% ( [[#den%20Elzen--2016|den Elzen et al. 2016]] ). Although there are uncertainties in the extent to which countries will meet the conditional elements of their NDCs, the experience with the Cancun pledges has been positive, as countries will collectively meet their pledges by 2020, and even individual pledges will be met in most cases, although arguably helped by the COVID-19 pandemic ( [[#UNEP--2020|UNEP 2020]] ). In any case, the main challenge that remains is to close the emissions gap, the difference between what has been pledged and what needs to be achieved by 2030 to reach a 1.5°C compatible path (respectively 2°C) ( [[#Roelfsema--2020|Roelfsema et al. 2020]] ; [[#UNEP--2020|UNEP 2020]] , see also Cross-Chapter Box 4 in Chapter 4). In terms of participation of states in mitigation actions, the Paris Agreement performs better than the Kyoto Protocol. The latter contains mitigation targets only for developed countries listed in its Annex B, while the Paris Agreement extends binding procedural obligations in relation to mitigation contributions to all states. It is noted, however, that the Paris Agreement represented a weakening of commitments for those industrialised countries that were Parties to the Kyoto Protocol, although a strengthening for those that were not, and for developing countries ( [[#Oberthür--2020|Oberthür and Groen 2020]] ). Finally, some analysts have suggested that the recent proliferation of national mid-century net-zero targets – currently 127 countries have considered or adopted such targets – can be attributed, at least in part, to participation in the Paris Agreement and having agreed to its Article 4 ( [[#Climate%20Action%20Tracker--2020a|Climate Action Tracker 2020a]] ; [[#Day--2020|Day et al. 2020]] ).

In relation to the criterion of ''transformative potential'' , there is, as yet, limited empirical data or theoretical analysis on which to assess the Paris Agreement’s transformative potential. The IPCC ''Special Report on Global Warming of 1.5°C'' concluded that pathways limiting global warming to 1.5°C would require systems transitions that are ‘unprecedented in terms of scale’ ( [[#IPCC--2018b|IPCC 2018b]] ). There is limited evidence to suggest that this is underway, although there are arguments made that Paris has the right structure to achieve this. The linking of the UNFCCC financial apparatus, including the GCF, to the Paris Agreement, and the provisions on technology support and capacity building, provide potential avenues for promoting increased investment flows into low-carbon technologies and development pathways, as [[#Labordena--2017|Labordena et al. (2017)]] show in the case of solar energy development in Africa. Similarly, [[#Kern--2016|Kern and Rogge (2016)]] argue that the Paris Agreement’s global commitment towards complete decarbonisation may play a critical role in accelerating underlying system transitions, by sending a strong signal as to the actions needed by national governments and other international support. [[#Victor--2019|Victor et al. (2019)]] argue that international cooperation that enhances transformative potential needs to operate at the sectoral level, as the barriers to transformation are highly specific to each sector; the Paris Agreement’s broad consensus around a clear level of ambition sends a strong signal on what is needed in each sector, but on its own will do little unless bolstered with sector-specific action (Geels et al. 2019). On the less optimistic side, it is noted that the extent of the ‘investment signal’ sent by the Agreement to business is unclear ( [[#Kemp--2018|Kemp 2018]] ), and it is also unclear to what extent the Paris Agreement is fostering investment in break-through technologies. United States non-cooperation from 2017 to 2020 posed a significant threat to adequate investment flows through the GCF ( [[#Chai--2017|Chai et al. 2017]] ; [[#Urpelainen--2018|Urpelainen and Van de Graaf 2018]] ).

In relation to the criterion of ''distributive outcomes,'' the Paris Agreement performs well in some respects but less well in others, and its performance relative to the Kyoto Protocol is arguably lower in respect of some indicators such as industrialised country leadership, and differentiation in favour of developing countries. While the Kyoto Protocol implemented a multilaterally agreed burden-sharing arrangement set out in the UNFCCC and reflected in Annex-based differentiation in mitigation obligations, the Paris Agreement relies on NDCs, accompanied by self-assessments of the fairness of these contributions; some of these do not accord with equity principles of international environmental law, although it is worth noting that the Kyoto Protocol was also not fully consistent with such principles. At present, mechanisms in the Paris Agreement for promoting equitable burden sharing and evaluating the fairness of Parties’ contributions are undefined, although numerous proposals have been developed in the literature [[#Herrala--2016|Herrala and Goel 2016]] ; ( [[#Ritchie--2017|Ritchie and Reay 2017]] ; [[#Robiou%20du%20Pont--2017|Robiou du Pont et al. 2017]] ; [[#Alcaraz--2019|Alcaraz et al. 2019]] ; [[#Sheriff--2019|Sheriff 2019]] ) ( [[#14.3.2.3|Section 14.3.2.3]] ). [[#Zimm--2020|Zimm and Nakicenovic (2020)]] analysed the first set of NDCs and concluded that they would result in a decrease in the inequality of per capita emissions across countries. In relation to other indicators, such as the provision of support, the distributive outcomes of the Paris Agreement are dependent on the availability of support through mechanisms such as the GCF to meet the mitigation and adaptation financing needs of developing countries ( [[#Antimiani--2017|Antimiani et al. 2017]] ; [[#Chan--2018|Chan et al. 2018]] ). One study suggests that the implementation of the emissions reduction objectives stated in the NDCs implies trade-offs with poverty reduction efforts needed to achieve SDGs ( [[#Campagnolo--2019|Campagnolo and Davide 2019]] ), while other studies offer evidence that the immediate economic, environmental, and social benefits of mitigation in line with developing countries’ NDCs exceed those NDCs’ costs, and ultimately align with the SDGs ( [[#Antwi-Agyei--2018|Antwi-Agyei et al. 2018]] ; [[#Vandyck--2018|Vandyck et al. 2018]] ; [[#Caetano--2020|Caetano et al. 2020]] ) (Chapter 17). In relation to the promotion of co-benefits, the Paris Agreement has enhanced mechanisms for promoting co-benefits (e.g., in some cases for biodiversity conservation through the endorsement of REDD+ initiatives and activities) and linkages to sustainable development (e.g., through the Article 6.4 mechanism). Finally, in its preambular text the Paris Agreement endorses both a human rights perspective and the concept of just transitions, creating potential hooks for further elaboration and expansion of these principles in mitigation actions.

On the criterion of ''economic performance'' , the Paris Agreement’s performance is potentially enhanced by the capacity for Parties to link mitigation policies, therefore improving aggregate cost-effectiveness. Voluntary cooperation under Article 6 of the Paris Agreement could facilitate such linkage of mitigation policies ( [[#Chan--2018|Chan et al. 2018]] ). A combination of common accounting rules and the absence of restrictive criteria and conditions on the use of ITMOs could accelerate linkage and increase the latitude of Parties to scale up the ambition of their NDCs. However, significant question marks remain over how the environmental integrity of traded emissions reductions can be ensured ( [[#Mehling--2019|Mehling 2019]] ). The ability of Article 6 to contribute to the goal of the Paris Agreement will depend on the extent to which the rules ensure environmental integrity and avoid double counting, while utilising the full potential of cooperative efforts ( [[#Michaelowa--2019a|Michaelowa et al. 2019a]] ; [[#Schneider--2019|Schneider et al. 2019]] ).

In relation to the criterion of ''institutional strength'' , the Paris Agreement’s signalling and guidance function is, however, arguably high. The Paris Agreement has the potential to interact with complementary approaches to climate governance emerging beyond it ( [[#Held--2018|Held and Roger 2018]] ). It may also be used by public-sector organisations – organised and mobilised in many countries and transnationally – as a point of leverage in domestic politics to encourage countries to take costly mitigation actions ( [[#Keohane--2016|Keohane and Oppenheimer 2016]] ). More broadly, the Paris Agreement’s architecture provides flexibility for decentralised forms of governance ( [[#Jordan--2015|Jordan et al. 2015]] ; [[#Victor--2016|Victor 2016]] ) ( [[#14.5|Section 14.5]] ). The Agreement has served a catalytic and facilitative role in enabling and facilitating climate action from non-state and sub-state actors ( [[#Chan--2015|Chan et al. 2015]] ; [[#Chan--2016|Chan et al. 2016]] ; [[#Hale--2016|Hale 2016]] ; [[#Bäckstrand--2017|Bäckstrand et al. 2017]] ; [[#Kuyper--2018b|Kuyper et al. 2018b]] ). Such action could potentially ‘bridge’ the ambition gap created by insufficient NDCs from Parties ( [[#Hsu--2019b|Hsu et al. 2019b]] ). The 2018 UNEP Emissions Gap Report estimates that if ‘cooperative initiatives are scaled up to their fullest potential’, the impact of non-state and sub-national actors could be up to 1–23 GtCO 2 -eq yr –1 by 2030 compared to current policy, which could bridge the gap ( [[#Lui--2021|Lui et al. 2021]] ). However, at present such a contribution is limited ( [[#Michaelowa--2017|Michaelowa and Michaelowa 2017]] ; [[#UNEP--2018a|UNEP 2018a]] ). Non-state actors are also playing a role in enhancing the ambition of individual NDCs by challenging their adequacy in national courts ( [[IPCC:Wg3:Chapter:Chapter-13|Chapter 13]] and [[#14.5.3|Section 14.5.3]] ).

The Paris Agreement’s institutional strength in terms of ‘rules and standards to facilitate collective action’ is disputed given the current lack of comparable information in NDCs ( [[#Peters--2017|Peters et al. 2017]] ; [[#Pauw--2018|Pauw et al. 2018]] ; [[#Mayer--2019|Mayer 2019]] ; [[#Zihua--2019|Zihua et al. 2019]] ), and the extent to which its language, as well as that of the Rulebook, strikes a balance in favour of discretion over prescriptiveness ( [[#Rajamani--2019|Rajamani and Bodansky 2019]] ). Similarly, in terms of ‘mechanisms to enhance transparency and accountability’, although detailed rules relating to transparency have been developed under the Paris Rulebook, these rules permit Parties considerable self-determination in the extent and manner of application ( [[#Rajamani--2019|Rajamani and Bodansky 2019]] ), and may not lead to further ambition ( [[#Weikmans--2020|Weikmans et al. 2020]] ). Further the Paris Agreement’s compliance committee is facilitative and designed to ensure compliance with the procedural obligations in the Agreement rather than with the NDCs themselves, which are not subject to obligations of result. The Paris Agreement does, however, seek to support the building of transparency-related capacity of developing countries, potentially triggering institutional capacity-building at the national, sub-national and sectoral levels ( [[#14.3.2.7|Section 14.3.2.7]] ).

Ultimately, the overall effectiveness of the Paris Agreement depends on its ability to lead to ratcheting up of collective climate action to meet the long-term global temperature goal ( [[#Bang--2016|Bang et al. 2016]] ; [[#Christoff--2016|Christoff 2016]] ; [[#Young--2016|Young 2016]] ; [[#Dimitrov--2019|Dimitrov et al. 2019]] ; [[#Gupta--2019|Gupta and van Asselt 2019]] ). As noted above, there is some evidence that this is already occurring. The design of the Paris Agreement, with ‘nationally determined’ contributions at its centre, countenances an initial shortfall in collective ambition in relation to the long-term global temperature goal on the understanding and expectation that Parties will enhance the ambition of their NDCs over time (Article 4). This is essential given the current shortfall in ambition. The pathways reflecting current NDCs, according to various estimates, imply global warming in the range of 3°C by 2100 ( [[#UNFCCC--2016b|UNFCCC 2016b]] ; [[#UNEP--2018a|UNEP 2018a]] ) (Box 4.3). NDCs will need to be substantially scaled up if the temperature goal of the Paris Agreement is to be met ( [[#Rogelj--2016|Rogelj et al. 2016]] ; [[#Rogelj--2018|Rogelj et al. 2018]] ; [[#Höhne--2017|Höhne et al. 2017]] , 2018; [[#UNEP--2020|UNEP 2020]] ). The Paris Agreement’s ‘ambition cycle’ is designed to trigger such enhanced ambition over time. Some studies find that like-minded climate mitigation clubs can deliver substantial emissions reductions ( [[#Hovi--2017|Hovi et al. 2017]] ) and are reasonably stable despite the departure of a major emitter such as the United States ( [[#Sprinz--2018|Sprinz et al. 2018]] ); other studies find that conditional commitments in the context of a pledge and review mechanism are unlikely to substantially increase countries’ contributions to emissions reductions ( [[#Helland--2017|Helland et al. 2017]] ), and hence need to be complemented by the adoption of instruments designed differently from the Paris Agreement ( [[#Barrett--2016|Barrett and Dannenberg 2016]] ). In any case, high (but not perfect) levels of mean compliance rates with the Paris Agreement have to be assumed for reaching the ‘well below 2°C’ temperature goal ( [[#Sælen--2020|Sælen 2020]] ; [[#Sælen--2020|Sælen et al. 2020]] ). This is by no means assured.

In conclusion, it remains to be seen whether the Paris Agreement will deliver the collective ambition necessary to meet the temperature goal. While the Paris Agreement does not contain strong and stringent obligations of result for major emitters, backed by a demanding compliance system, it establishes binding procedural obligations, lays out a range of normative expectations, and creates mechanisms for regular review, stock taking, and revision of NDCs. In combination with complementary approaches to climate governance, engagement of a wide range of non-state and sub-national actors, and domestic enforcement mechanisms, these have the potential to deliver the necessary collective ambition and implementation. Whether it will do so, remains to be seen.

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