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

== 14.3 The UNFCCC and the Paris Agreement ==

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=== 14.3.1 The UN Climate Change Regime ===

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==== 14.3.1.1 Instruments and Milestones ====

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The international climate change regime, in evolution for three decades, comprises the 1992 UNFCCC, the 1997 Kyoto Protocol, and the 2015 Paris Agreement. The UNFCCC is a ‘framework’ convention, capturing broad convergence among states on an objective, a set of principles, and general obligations relating to mitigation, adaptation, reporting and support. The UNFCCC categorises Parties into Annex I and Annex II. Annex I Parties, comprising developed country Parties, have a goal to return, individually or jointly, their GHG emissions to 1990 levels by 2000. Annex II Parties, comprising developed country Parties except for those with economies in transition, have additional obligations relating to the provision of financial and technology support. Parties including developing country Parties, characterised as non-Annex-I Parties, have reporting obligations, as well as obligations to take policies and measures on mitigation and adaptation. The UNFCCC also establishes the institutional building blocks for global climate governance. Both the 1997 Kyoto Protocol and the 2015 Paris Agreement are distinct but ‘related legal instruments’ in that only Parties to the UNFCCC can be Parties to these later instruments.

The Kyoto Protocol specifies GHG emissions reduction targets for the 2008–2012 commitment period for countries listed in its Annex B (which broadly corresponds to Annex I to the UNFCCC) ( [[#UNFCCC--1997|UNFCCC 1997]] , Art. 3 and Annex B). The Kyoto Protocol entered into force in 2005. Shortly thereafter, states began negotiating a second commitment period under the Protocol for Annex B Parties, as well as initiating a process under the UNFCCC to consider long-term cooperation among all Parties.

At the 13th Conference of the Parties to the UNFCCC (COP13) in Bali in 2007, Parties adopted the Bali Action Plan which launched negotiations aimed at an agreed outcome enhancing the UNFCCC’s ‘full, effective and sustained implementation’. The agreed outcome was to be adopted at COP15 in Copenhagen in 2009, but negotiations failed to deliver a consensus document. The result instead was the Copenhagen Accord '','' which was taken note of by the COP. While it was a political agreement with no formal legal status under the UNFCCC, it reflected significant progress on several fronts and set in place the building blocks for the Paris Agreement, namely: setting a goal of limiting global temperature increase to below 2°C; calling on all countries to put forward mitigation pledges; establishing broad new terms for the reporting and verification of countries’ actions; setting a goal of mobilising USD100 billion a year by 2020 from a wide variety of sources, public and private, bilateral and multilateral, including alternative sources of finance; and, calling for the establishment of a new Green Climate Fund and Technology Mechanism ( [[#Rajamani--2010|Rajamani 2010]] ; [[#Rogelj--2010|Rogelj et al. 2010]] ; [[#UNFCCC--2010a|UNFCCC 2010a]] ). One hundred and forty states endorsed the Copenhagen Accord, with 85 countries entering pledges to reduce their emissions or constrain their growth by 2020 ( [[#Christensen--2019|Christensen and Olhoff 2019]] ).

At COP16 in Cancun in 2010, Parties adopted a set of decisions termed the Cancun Agreements that effectively formalised the core elements of the Copenhagen Accord, and the pledges states made, under the UNFCCC. The Cancun Agreements were regarded as an interim arrangement through to 2020, and Parties left the door open to further negotiations, in line with negotiations launched in 2005, toward a legally-binding successor to the Kyoto Protocol ( [[#Freestone--2010|Freestone 2010]] ; [[#Liu--2011a|Liu 2011a]] ). Collectively the G20 states are on track to meeting the mid level of their Cancun pledges, although there is uncertainty about some individual pledges. However, there is significant gap between annual emissions expected under full implementation of pledges and the level consistent with the 2°C goal ( [[#Christensen--2019|Christensen and Olhoff 2019]] ).

At the 2011 Durban climate conference, Parties launched negotiations for ‘a Protocol, another legal instrument or agreed outcome with legal force’ with a scheduled end to the negotiations in 2015 ( [[#UNFCCC--2012|UNFCCC 2012]] , Dec. 1, para. 2). At the 2012 Doha climate conference, Parties adopted a second commitment period for the Kyoto Protocol, running from 2013–2020. The Doha Amendment entered into force on 31 December 2020. Given the subsequent adoption of the Paris Agreement, the Kyoto Protocol is unlikely to continue beyond 2020 ( [[#Bodansky--2017a|Bodansky et al. 2017a]] ). At the end of the compliance assessment period under the Kyoto Protocol, Annex B Parties were in full compliance with their targets for the first commitment period; in some cases through the use of the Protocol’s flexibility mechanisms ( [[#Shishlov--2016|Shishlov et al. 2016]] ).

Although both the Kyoto Protocol and Paris Agreement are under the UNFCCC, they are generally seen as representing fundamentally different approaches to international cooperation on climate change ( [[#Held--2018|Held and Roger 2018]] ; [[#Falkner--2016b|Falkner 2016b]] ). The Paris Agreement has been characterised as a ‘decisive break’ from the Kyoto Protocol ( [[#Keohane--2016|Keohane and Oppenheimer 2016]] ). Some note that the mitigation efforts under the Kyoto Protocol take the form of targets that, albeit based on national self-selection, were part of the multilateral negotiation process, whereas under the Paris Agreement Parties make Nationally Determined Contributions. The different approaches have been characterised by some as a distinction between a ‘top down’ and ‘bottom up’ approach (Bodansky and Rajamani 2016; [[#Bodansky--2016|Bodansky et al. 2016]] ; [[#Chan--2016|Chan et al. 2016]] ; [[#Doelle--2016|Doelle 2016]] ) but others disagree with such a characterisation, pointing to continuities within the regime, for example, in terms of rules for reporting and review, and crossover and use of common institutional arrangements ( [[#Depledge--2017|Depledge 2017]] ; [[#Allan--2019|Allan 2019]] ). Some note, in any case, that the Kyoto Protocol’s core obligations are substantive obligations of result, while many of the Paris Agreement’s core obligations are procedural obligations, complemented by obligations of conduct ( [[#Rajamani--2016a|Rajamani 2016a]] ; [[#Mayer--2018a|Mayer 2018a]] ).

The differences between and continuities in the three treaties that comprise the UN climate regime are summarised in Table 14.3. The Kyoto targets apply only to Annex I Parties, but the procedural obligations relating to NDCs in the Paris Agreement apply to all Parties, with flexibilities in relation to some obligations for Least Developed Countries (LDCs), Small Island Developing States (SIDS), and developing countries that need them in light of their capacities. The Kyoto targets are housed in its Annex B, therefore requiring a formal process of amendment for revision, whereas the Paris NDCs are located in an online registry that is maintained by the Secretariat, but to which Parties can upload their own NDCs. The Kyoto Protocol allows Annex B Parties to use three market-based mechanisms – the Clean Development Mechanism (CDM), Joint Implementation and International Emissions Trading – to fulfil a part of their GHG targets. The Paris Agreement recognises that Parties may choose to cooperate voluntarily on markets, in the form of cooperative approaches under Article 6.2, and a mechanism with international oversight under Article 6.4, subject to guidance and rules that are yet to be adopted. These rules relate to integrity and accounting ( [[#La%20Hoz%20Theuer--2019|La Hoz Theuer et al. 2019]] ). Article 5 also provides explicit endorsement of reducing emissions from deforestation and forest degradation and fostering conservation (REDD+). The Kyoto Protocol contains an extensive reporting and review process, backed by a compliance mechanism. This mechanism includes an enforcement branch, to ensure compliance, and sanction non-compliance (through the withdrawal of benefits such as participation in market-based mechanisms), with its national system requirements, and GHG targets. By contrast, the Paris Agreement relies on informational requirements and flows to enhance the clarity of NDCs, and to track progress in the implementation and achievement of NDCs.

'''Table 14.3 | Continuities in and differences between the UNFCCC, Paris Agreement and the Kyoto Protocol.'''

{| class="wikitable"
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! '''Feature'''

! UNFCCC

! Kyoto Protocol

! Paris Agreement

|-
| '''Objective'''

| To stabilise GHGs in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system, in a timeframe to protect food security, enable natural ecosystem adaptability and permit economic development in a sustainable manner

| Primarily mitigation-focused (although in pursuit of the UNFCCC objective)

| Mitigation in line with a long-term temperature goal, adaptation and finance goals, as well as sustainable development and equity (also, in pursuit of the UNFCCC objective)

|-
| '''Architecture'''

| ‘Framework’ agreement with agreement on principles such as ‘common but differentiated responsibilities and respective capabilities’), division of countries into Annexes, with different groups of countries with differentiated commitments

| Differentiated targets, based on national offers submitted to the multilateral negotiation process, and multilaterally negotiated common metrics

| Nationally Determined Contributions subject to transparency, multilateral consideration of progress, common metrics in inventories and accounting

|-
| '''Coverage of mitigation-related commitments'''

| Annex I Parties with a GHG stabilisation goal, all Parties to take policies and measures

| UNFCCC Annex I/Kyoto Annex B Parties only

| All Parties

|-
| '''Targets'''

| GHG stabilisation goal for Annex I Parties (‘quasi target’)

| Legally-binding, differentiated mitigation targets inscribed in treaty

| Non-binding (in terms of results) contributions incorporated in Parties’ NDCs, and provisions including those relating to highest possible ambition, progression and ‘common but differentiated responsibilities and respective capabilities’, in light of different national circumstances

|-
| '''Timetable'''

| Aim to return to 1990 levels of GHGs by 2000

| Two commitment periods (2008–2012; 2013–2020)

| Initial NDCs for timeframes from 2020 running through to 2025 or 2030 with new or updated NDCs every five years, and encouragement to submit long-term low-GHG emission development strategies

|-
| '''Adaptation'''

| Parties to cooperate in preparing for adaptation to the impacts of climate change

| Parties to formulate and implement national adaptation measures, share of proceeds from CDM to fund adaptation

| Qualitative global goal on adaptation to enhance adaptative capacity and resilience, and reduce vulnerability, Parties to undertake national adaptation planning and implementation

|-
| '''Loss and Damage'''

| Not covered

| Not covered

| Cooperation and facilitation to enhance understanding, action and support for loss and damage, including through the Warsaw International Mechanism on Loss and Damage under the UNFCCC

|-
| '''Transparency'''

| National communications from Parties, with differing content and set to differing timeframes for different categories of Parties

| Reporting and review – Annex B Parties only

| Enhanced transparency framework and five-yearly global stocktake for a collective assessment of progress towards goals – all Parties

|-
| '''Support'''

| Annex II commitments relating to provision of finance, development and transfer of technology to developing countries

| Advances UNFCCC Annex II commitments relating to provision of finance, development and transfer of technology to developing countries

| Enhances reporting in relation to support, expands the base of donors, and tailors support to the needs and capacities of developing countries

|-
| '''Implementation'''

| National implementation, communication on implementation

| Market mechanisms (International Emissions Trading, Joint Implementation, CDM)

| Voluntary cooperation on mitigation (through market-based and non-market approaches); encouragement of REDD+ (guidance and rules under negotiation)

|-
| '''Compliance'''

| Multilateral consultative process, never adopted

| Compliance committee with facilitative and enforcement branches; sanctions for non-compliance

| Committee to promote compliance and facilitate implementation; no sanctions

|}

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==== 14.3.1.2 Negotiating Context and Dynamics ====

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The 2015 Paris Agreement was negotiated in a starkly different geopolitical context to that of the 1992 UNFCCC and the 1997 Kyoto Protocol ( [[#Streck--2013|Streck and Terhalle 2013]] ; [[#Ciplet--2015|Ciplet et al. 2015]] ). The ‘rupturing binary balance of superpowers’ of the 1980s had given way to a multipolar world with several distinctive trends: emerging economies began challenging US dominance ( [[#Ciplet--2015|Ciplet et al. 2015]] ); industrialised countries’ emissions peaked in the 2010s and started declining, while emissions from emerging economies began to grow ( [[#Falkner--2019|Falkner 2019]] ); the EU stretched eastwards and became increasingly supra-national ( [[#Kinley--2020|Kinley et al. 2020]] ); disparities within the group of developing countries increased ( [[#Ciplet--2015|Ciplet et al. 2015]] ); and the role of non-state actors in mitigation efforts has grown more salient (Bäckstrand et al. 2017; [[#Kuyper--2018b|Kuyper et al. 2018b]] ; [[#Falkner--2019|Falkner 2019]] ). The rise of emerging powers, many of whom now have ‘veto power’, however, some noted, did not detract from the unequal development and inequality at the heart of global environmental politics ( [[#Hurrell--2012|Hurrell and Sengupta 2012]] ).

In this altered context, unlike in the 1990s when the main cleavages were between the EU and the US ( [[#Hurrell--2012|Hurrell and Sengupta 2012]] ), US–China ‘great power politics’ came to be seen as determinative of outcomes in the climate change negotiations ( [[#Terhalle--2013|Terhalle and Depledge 2013]] ). The US–China joint announcement (Whitehouse 2014), for instance, before the 2014 Lima climate conference, brokered the deal on differentiation that came to be embodied in the Paris Agreement ( [[#Rajamani--2016a|Rajamani 2016a]] ; [[#Ciplet--2017|Ciplet and]] [[#Roberts--2017|Roberts 2017]] ). Others have identified, on the basis of economic standing, political influence, and emissions levels, three influential groups – the first comprising the USA with Japan, Canada, and Russia, the second comprising the EU and the third comprising China, India and Brazil ( [[#Brenton--2013|Brenton 2013]] ). The emergence of the Major Economies Fora, among other climate clubs (discussed in [[#14.2.2|Section 14.2.2]] ) reflects this development ( [[#Brenton--2013|Brenton 2013]] ). It also represents a ‘minilateral’ forum, built on a recognition of power asymmetries, in which negotiating compromises are politically tested and fed into multilateral processes ( [[#Falkner--2016a|Falkner 2016a]] ).

Beyond these countries, in the decade leading up to the Paris climate negotiations, increasing differences within the group of developing countries divided the 134-strong developing country alliance of the G77/China into several interest-based coalitions ( [[#Vihma--2011|Vihma et al. 2011]] ; [[#Bodansky--2017b|Bodansky et al. 2017b]] ). A division emerged between the vulnerable least developed and small island states on the one side and rapidly developing economies, the BASIC (Brazil, South Africa, India and China) on the other, as the latter are ‘decidedly not developed but not wholly developing’ ( [[#Hochstetler--2013|Hochstetler and Milkoreit 2013]] ). This fissure in part led to the High Ambition Coalition in Paris between vulnerable countries and the more progressive industrialised countries ( [[#Ciplet--2017|Ciplet and]] [[#Roberts--2017|Roberts 2017]] ). A division also emerged between the BASIC countries ( [[#Hurrell--2012|Hurrell and Sengupta 2012]] ), that each have distinctive identities and positions ( [[#Hochstetler--2013|Hochstetler and Milkoreit 2013]] ). In the lead up to the Paris negotiations, China and India formed the Like-Minded Developing Countries with the Organization of the Petroleum Exporting Countries (OPEC) and the Bolivarian Alliance for the Peoples of our Americas (ALBA) countries, to resist the erosion of differentiation in the regime. Yet, the ‘complex and competing’ identities of India and China, with differing capacities, challenges and self-images, have also influenced the negotiations ( [[#Ciplet--2017|Ciplet and]] [[#Roberts--2017|Roberts 2017]] ; [[#Rajamani--2017|Rajamani 2017]] ). Other developing countries’ coalitions also played an important role in striking the final deal in Paris. The Alliance of Small Island States, despite their lack of structural power, played a leading role, in particular in relation to the inclusion of the 1.5°C long-term temperature goal in the UN climate regime (Agueda Corneloup and Mol 2014; [[#Ourbak--2018|Ourbak and Magnan 2018]] ). The Association of the Latin American and Caribbean Countries (AILAC) that emerged in 2012 also played a decisive role in fostering ambition ( [[#Edwards--2017|Edwards et al. 2017]] ; [[#Watts--2018|Watts and Depledge 2018]] ).

Leadership is essential to reaching international agreements and overcoming collective action problems ( [[#Parker--2015|Parker et al. 2015]] ). The Paris negotiations were faced, as a reflection of the multipolarity that had emerged, with a ‘fragmented leadership landscape’ with the USA, EU, and China being perceived as leaders at different points in time and to varying degrees ( [[#Karlsson--2012|Karlsson et al. 2012]] ; [[#Parker--2014|Parker et al. 2014]] ). Small island states are also credited with demonstrating ‘moral leadership’ (Agueda Corneloup and Mol 2014), and non-state and sub-national actors are beginning to be recognised as pioneers and leaders ( [[#Wurzel--2019|Wurzel et al. 2019]] ). There is also a burgeoning literature on the emergence of diffused leadership and the salience of followers ( [[#Parker--2014|Parker et al. 2014]] ; [[#Busby--2020|Busby and Urpelainen 2020]] ).

It is in the context of this complex, multipolar and highly differentiated world – with a heterogeneity of interests, constraints and capacities, increased contestations over shares of the carbon and development space, as well as diffused leadership – that the Paris Agreement was negotiated. This context fundamentally influenced the shape of the Paris Agreement, in particular on issues relating to its architecture, ‘legalisation’ ( [[#Karlas--2017|Karlas 2017]] ) and differentiation ( [[#Bodansky--2017b|Bodansky et al. 2017b]] ; [[#Kinley--2020|Kinley et al. 2020]] ), all of which are discussed below.

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=== 14.3.2 Elements of the Paris Agreement Relevant to Mitigation ===

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The 2015 Paris Agreement to the UNFCCC, which entered into force on 4 November 2016, and has 193 Parties as of March 2022, is at the centre of international cooperative efforts for climate change mitigation and adaptation in the post-2020 period. Although its legal form was heavily disputed, especially in the initial part of its four-year negotiating process ( [[#Rajamani--2015|Rajamani 2015]] ; [[#Maljean-Dubois--2016|Maljean-Dubois and Wemaëre 2016]] ; [[#Bodansky--2017b|Bodansky et al. 2017b]] ; [[#Klein--2017|Klein et al. 2017]] ), the Paris Agreement is a treaty containing provisions of differing levels of ‘bindingness’ ( [[#Bodansky--2016|Bodansky 2016]] ; [[#Oberthür--2016|Oberthür and Bodle 2016]] ; [[#Rajamani--2016b|Rajamani 2016b]] ). The legal character of provisions within a treaty, and the extent to which particular provisions lend themselves to assessments of compliance or non-compliance, depends on factors such as the normative content of the provision, the precision of its terms, the language used, and the oversight mechanisms in place ( [[#Werksman--2010|Werksman 2010]] ; [[#Bodansky--2015|Bodansky 2015]] ; [[#Oberthür--2016|Oberthür and Bodle 2016]] ; [[#Rajamani--2016b|Rajamani 2016b]] ). Assessed on these criteria, the Paris Agreement contains the full spectrum of provisions, from hard to soft law ( [[#Rajamani--2016b|Rajamani 2016b]] ; [[#Pickering--2019|Pickering et al. 2019]] ) and even ‘non-law’, provisions that do not have standard-setting or normative content but which play a narrative-building and context-setting role ( [[#Rajamani--2016b|Rajamani 2016b]] ). The Paris Agreement, along with the UNFCCC and the Kyoto Protocol, can be interpreted in light of the customary international law principle of harm prevention according to which states must exercise due diligence in seeking to prevent activities within their jurisdiction from causing extraterritorial environmental harm ( [[#Mayer--2016a|Mayer 2016a]] ; [[#Maljean-Dubois--2019|Maljean-Dubois 2019]] ). The key features of the Paris Agreement are set out in Box 14.1.

Figure 14.1 illustrates graphically the key features of the Paris Agreement. The Paris Agreement is based on a set of binding procedural obligations requiring Parties to ‘prepare, communicate, and maintain’ ‘Nationally Determined Contributions’ (NDCs) ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 4.2) every five years ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 4.9). These obligations are complemented by: (1) an ‘ambition cycle’ that expects Parties, informed by five-yearly global stocktakes (Art. 14), to submit successive NDCs representing a progression on their previous NDCs ( [[#UNFCCC--2015a|UNFCCC 2015a]] ; [[#Bodansky--2017b|Bodansky et al. 2017b]] ), and (2) an ‘enhanced transparency framework’ that places extensive informational demands on Parties, tailored to capacities, and establishes review processes to enable tracking of progress towards achievement of NDCs ( [[#Oberthür--2016|Oberthür and Bodle 2016]] ). In contrast to the Kyoto Protocol with its internationally inscribed targets and timetable for emissions reduction for developed countries, the Paris Agreement contains Nationally Determined Contributions embedded in an international system of transparency and accountability for all countries ( [[#Doelle--2016|Doelle 2016]] ; [[#Maljean-Dubois--2016|Maljean-Dubois and Wemaëre 2016]] ) accompanied by a shared global goal, in particular in relation to a temperature limit.

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[[File:aed0e19e78b0b2d765ef8776cc7ed2f0 IPCC_AR6_WGIII_Figure_14_1.png]]

'''Figure 14.1 | Key features of the Paris Agreement.''' Arrows illustrate the interrelationship between the different features of the Paris Agreement, in particular between the Agreement’s goals, required actions through NDCs, support (finance, technology and capacity building), transparency framework and global stocktake process. The figure also represents points of interconnection with domestic mitigation measures, whether taken by state Parties or by non-state actors (NSAs). This figure is illustrative rather than exhaustive of the features and interconnections.

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==== 14.3.2.1 Context and Purpose ====

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The preamble of the Paris Agreement lists several factors that provide the interpretative context for the Agreement ( [[#Bodansky--2017b|Bodansky et al. 2017b]] ; [[#Carazo--2017|Carazo 2017]] ), including a reference to human rights. The human rights implications of climate impacts garnered particular attention in the lead up to Paris ( [[#Duyck--2015|Duyck 2015]] ; [[#Mayer--2016b|Mayer 2016b]] ). In particular, the Human Rights Council, its special procedures mechanisms, and the Office of the High Commissioner for Human Rights, through a series of resolutions, reports, and activities, advocated a rights-based approach to climate impacts, and sought to integrate this approach in the climate change regime. The Paris Agreement’s preambular recital on human rights recommends that Parties, ‘when taking action to address human rights’, take into account ‘their respective obligations on human rights’ ( [[#UNFCCC--2015a|UNFCCC 2015a]] , preambular recital 14), a first for an environmental treaty ( [[#Knox--2016|Knox 2016]] ). The ‘respective obligations’ referred to in the Paris Agreement could potentially include those relating to the right to life ( [[#UNGA--1948|UNGA 1948]] , Art. 3, 1966, Art. 6), right to health ( [[#UNGA--1966b|UNGA 1966b]] , Art. 12), right to development, right to an adequate standard of living, including the right to food ( [[#UNGA--1966b|UNGA 1966b]] , Art. 11), which has been read to include the right to water and sanitation ( [[#CESCR--2002|CESCR 2002]] , 2010), the right to housing ( [[#CESCR--1991|CESCR 1991]] ), and the right to self-determination, including as applied in the context of indigenous peoples ( [[#UNGA--1966a|UNGA 1966a]] ,b, Art. 1). In addition, climate impacts contribute to displacement and migration ( [[#Mayer--2016|Mayer and Crépeau 2016]] ; [[#McAdam--2016|McAdam 2016]] ), and have disproportionate effects on women ( [[#Pearse--2017|Pearse 2017]] ). There are differing views on the value and operational impact of the human rights recital in the Paris Agreement ( [[#Adelman--2018|Adelman 2018]] ; [[#Boyle--2018|Boyle 2018]] ; [[#Duyck--2018|Duyck et al. 2018]] ; [[#Rajamani--2018|Rajamani 2018]] ; [[#Savaresi--2018|Savaresi 2018]] ; [[#Knox--2019|Knox 2019]] ). Notwithstanding proposals from some Parties and stakeholders to mainstream and operationalise human rights in the climate regime post-Paris ( [[#Duyck--2018|Duyck et al. 2018]] ), and references to human rights in COP decisions, the 2018 Paris Rulebook contains limited and guarded references to human rights ( [[#Duyck--2019|Duyck 2019]] ; [[#Rajamani--2019|Rajamani 2019]] ) ( [[#14.5.1.2|Section 14.5.1.2]] ). In addition to the reference to human rights, the preamble also notes the importance of ‘ensuring the integrity of all ecosystems, including oceans and the protection of biodiversity’ which provides opportunities for integrating and mainstreaming other environmental protections.

The overall purpose of international cooperation through the Paris Agreement is to enhance the implementation of the UNFCCC, including its objective of stabilising atmospheric GHG concentrations ‘at a level that would prevent dangerous anthropogenic interference with the climate system’ ( [[#UNFCCC--1992|UNFCCC 1992]] , Art. 2). The Paris Agreement aims to strengthen the global response to the threat of climate change, in the context of sustainable development and efforts to eradicate poverty, by ''inter alia'' ‘[h]olding 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’ ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 2(1)(a)). There is an ongoing structured expert dialogue under the UNFCCC in the context of the second periodic review of the long-term global goal (the first was held between 2013–2015) aimed at enhancing understanding of the long-term global goal, pathways to achieving it, and assessing the aggregate effect of steps taken by Parties to achieve the goal.

Some authors interpret the Paris Agreement’s temperature goal as a single goal with two inseparable elements, the well below 2°C goal pressing towards 1.5°C ( [[#Rajamani--2018|Rajamani and Werksman 2018]] ), but others interpret the goal as a unitary one of 1.5°C with minimal overshoot ( [[#Mace--2016|Mace 2016]] ). Yet others interpret 1.5°C as the limit within the long-term temperature goal, and that it ‘signals an increase in both the margin and likelihood by which warming is to be kept below 2°C’ ( [[#Schleussner--2016|Schleussner et al. 2016]] ). Although having a long-term goal has clear advantages, the literature highlights the issue of credibility, given the lengthy timeframe involved ( [[#Urpelainen--2011|Urpelainen 2011]] ), and stresses that future regulators may have incentives to relax current climate plans, which could have a significant effect on the achieved GHG stabilisation level ( [[#Gerlagh--2015|Gerlagh and Michielsen 2015]] ).

As the risks of adverse climate impacts, even with a ‘well below’ 2°C increase, are substantial, the purpose of the Paris Agreement extends to increasing adaptive capacity and fostering climate resilience ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 2(1)(b)), as well as redirecting investment and finance flows ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. (2)(1)(c); [[#Thorgeirsson--2017|Thorgeirsson 2017]] ). The finance and adaptation goals are not quantified in the Paris Agreement itself but the temperature goal and the pathways they generate may, some argue, enable a quantitative assessment of the resources necessary to reach these goals, and the nature of the impacts requiring adaptation ( [[#Rajamani--2018|Rajamani and Werksman 2018]] ). The decision accompanying the Paris Agreement resolves to set a new collective quantified finance goal prior to 2025 (not explicitly limited to developed countries), with USD100 billion yr –1 as a floor ( [[#UNFCCC--2016a|UNFCCC 2016a]] , para. 53; [[#Bodansky--2017b|Bodansky et al. 2017b]] ). Article 2 also references sustainable development and poverty eradication, and thus implicitly underscores the need to integrate the SDGs in the implementation of the Paris Agreement ( [[#Sindico--2016|Sindico 2016]] ).

The Paris Agreement’s purpose is accompanied by an expectation that the Agreement ‘will be’ implemented to ‘reflect equity and the principle of common but differentiated responsibilities and respective capabilities (CBDRRC), in the light of different national circumstances’ ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 2.2). This provision generates an expectation that Parties will implement the agreement to reflect CBDRRC, and is not an obligation to do so ( [[#Rajamani--2016a|Rajamani 2016a]] ). Further, the inclusion of the term ‘in light of different national circumstances’ introduces a dynamic element into the interpretation of the CBDRRC principle. As national circumstances evolve, the application of the principle will also evolve ( [[#Rajamani--2016a|Rajamani 2016a]] ). This change in the articulation of the CBDRRC principle is reflected in the shifts in the nature and extent of differentiation in the climate change regime ( [[#Maljean-Dubois--2016|Maljean-Dubois 2016]] ; [[#Rajamani--2016a|Rajamani 2016a]] ; [[#Voigt--2016a|Voigt and Ferreira 2016a]] ), including through a shift towards ‘procedurally-oriented differentiation’ for developing countries ( [[#Huggins--2016|Huggins and Karim 2016]] ).

Although NDCs are developed by individual state Parties, the Paris Agreement requires that these are undertaken by Parties ‘with a view’ to achieving the Agreement’s purpose and collectively ‘represent a progression over time’ ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 3). The Paris Agreement also encourages Parties to align the ambition of their NDCs with the temperature goal through the Agreement’s ‘ambition cycle’, thus imparting operational relevance to the temperature goal ( [[#Rajamani--2018|Rajamani and Werksman 2018]] ).

Article 4.1 contains a further non-binding requirement that Parties ‘aim’ to reach global peaking of GHG ‘as soon as possible’ and to undertake rapid reductions thereafter to achieve net zero GHG emissions ‘in the second half of the century’. Some argue this implies a need to reach net zero GHG emissions in the third quarter of the 21st century ( [[#Rogelj--2015|Rogelj et al. 2015]] ; [[#IPCC--2018b|IPCC 2018b]] ) (Chapter 2, Table 2.4 and Cross-Chapter Box 3 in Chapter 3). To reach net zero CO 2 around 2050, in the short-term global net human-caused CO 2 emissions would need to fall by about 45% to 60% from 2010 levels by 2030 ( [[#IPCC--2018b|IPCC 2018b]] ). Achieving the Paris Agreement’s Article 4.1 aim potentially implies that global warming will peak and then follow a gradually declining path, potentially to below 1.5°C warming ( [[#Rogelj--2021|Rogelj et al. 2021]] ).

Albeit non-binding, Article 4.1 has acted as a catalyst for several national net-zero GHG targets, as well as net-zero CO 2 and GHG targets across local governments, sectors, businesses, and other actors ( [[#Day--2020|Day et al. 2020]] ). There is a wide variation in the targets that have been adopted – in terms of their legal character (policy statement, executive order or national legislation), scope (GHGs or CO 2 ) and coverage (sectors or economy-wide). National net-zero targets could be reflected in the long-term strategies that states are urged to submit under Article 4.19, but only a few states have submitted such strategies thus far. The Paris Rulebook, agreed at the Agreement’s first meeting of the Parties in 2018, further strengthens the operational relevance of the temperature goal by requiring Parties to provide information when submitting their NDCs on how these contribute towards achieving the objective identified in UNFCCC Article 2, and Paris Agreement Articles 2.1 (a) and 4.1 ( [[#UNFCCC--2019b|UNFCCC 2019b]] , Annex I, para. 7). Parties could in this context include information on how their short-term actions align with their long-term net zero GHG or CO 2 targets, thereby enhancing the credibility of their long-term goals.

At last count 131 countries had adopted or had net zero targets (whether of carbon or GHG) in the pipeline, covering 72% of global emissions. If these targets are fully implemented some estimate that this could bring temperature increase down to 2°C–2.4°C by 2100 as compared to current policies which are estimated to lead to a temperature increase of 2.9–3.2°C, and NDCs submitted to the Paris Agreement which are estimated to lead to a temperature increase of 2.4°C–2.9°C ( [[#Höhne--2021|Höhne et al. 2021]] ).

It is worth noting that Article 4.1 recognises that ‘peaking will take longer for developing countries’ and that the balance between emissions and removals needs to be on the ‘basis of equity, and in the context of sustainable development and efforts to eradicate poverty’. This suggests that not all countries are expected to reach net zero GHG emissions at the same time, or in the same manner. If global cost-effective 1.5°C and 2°C scenarios from integrated assessment models are taken, without applying an equity principle, the results suggest that domestic net zero GHG and CO 2 emissions would be reached a decade earlier than the global average in Brazil and the USA and later in India and Indonesia ( [[#van%20Soest--2021|van Soest et al. 2021]] ). By contrast, if equity principles are taken into account countries like Canada and the EU would be expected to phase out earlier than the cost-optimal scenarios indicate, and countries like China and Brazil could phase out emissions later, as well as other countries with lower per-capita emissions ( [[#van%20Soest--2021|van Soest et al. 2021]] ). Some suggest that the application of such fairness considerations could bring forward the net zero GHG date for big emitting countries by up to 15 to 35 years as compared to the global least-cost scenarios ( [[#Lee--2021b|Lee et al. 2021b]] ). In any case, reaching net zero GHG emissions requires to some extent the use of carbon dioxide removal (CDR) methods as there are important sources of non-CO 2 GHGs, such as methane and nitrous oxide, that cannot be fully eliminated ( [[#IPCC--2018b|IPCC 2018b]] ). However, there are divergent views on different CDR methods, policy choices determine the degree to which and the type of CDR methods that are considered and there is a patchwork of applicable regulatory instruments. There are also uncertainties and governance challenges associated with CDR methods which render tracking progress against net zero GHG emissions challenging ( [[#Mace--2021|Mace et al. 2021]] ). Researchers have noted that given the key role of CDR in net zero targets and 1.5°C compatible pathways, and the fact that it presents ‘significant costs to current and future generations’, it is important to consider what an equitable distribution of CDR might look like ( [[#UNFCCC--2019c|UNFCCC 2019c]] ; [[#Day--2020|Day et al. 2020]] ; [[#Lee--2021b|Lee et al. 2021b]] ).

<div id="14.3.2.2" class="h3-container"></div>

<span id="ndcs-progression-and-ambition"></span>
==== 14.3.2.2 NDCs, Progression and Ambition ====

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Each Party to the Paris Agreement has a procedural obligation to ‘prepare, communicate and maintain’ successive NDCs ‘that it intends to achieve’. Parties have a further procedural obligation to ‘pursue domestic mitigation measures’ ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 4.2). These procedural obligations are coupled with an obligation of conduct to make best efforts to achieve the objectives of NDCs ( [[#Rajamani--2016a|Rajamani 2016a]] ; [[#Mayer--2018b|Mayer 2018b]] ). Many states have adopted climate policies and laws, discussed in Chapter 13, and captured in databases ( [[#LSE--2020|LSE 2020]] ).

The framing and content of NDCs is thus largely left up to Parties, although certain normative expectations apply. These include developed country leadership through these Parties undertaking economy-wide absolute emissions reduction targets ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 4.4), as well as ‘progression’ and ‘highest possible ambition’ reflecting ‘common but differentiated responsibilities and respective capabilities in light of different national circumstances’ (Art. 4.3). There is ‘a firm expectation’ that for every five-year cycle a Party puts forward a new or updated NDC that is ‘more ambitious than their last’ ( [[#Rajamani--2016a|Rajamani 2016a]] ). While what represents a Party’s highest possible ambition and progression is not prescribed by the Agreement or elaborated in the Paris Rulebook ( [[#Rajamani--2019|Rajamani and Bodansky 2019]] ), these obligations could be read to imply a due diligence standard ( [[#Voigt--2016b|Voigt and Ferreira 2016b]] ).

In communicating their NDCs every five years ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 4.9), all Parties have an obligation to ‘provide the information necessary for clarity, transparency and understanding’ ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 4.8). These requirements are further elaborated in the Paris Rulebook ( [[#Doelle--2019|Doelle 2019]] ; [[#UNFCCC--2019b|UNFCCC 2019b]] ). This includes requirements – for Parties’ second and subsequent NDCs – to provide quantifiable information on the reference point, for example base year, reference indicators and target relative to the reference indicator ( [[#UNFCCC--2019b|UNFCCC 2019b]] , Annex I, para. 1). It also requires Parties to provide information on how they consider their contribution ‘fair and ambitious in light of different national circumstances’, and how they address the normative expectations of developed country leadership, progression and highest possible ambition ( [[#UNFCCC--2019b|UNFCCC 2019b]] , Annex I, para. 6). However, Parties are required to provide the enumerated information only ‘as applicable’ to their NDC ( [[#UNFCCC--2019b|UNFCCC 2019b]] , Annex I, para. 7). This allows Parties to determine the informational requirements placed on them through their choice of NDC. In respect of Parties’ first NDCs or NDCs updated by 2020, such quantifiable information ‘may’ be included, ‘as appropriate’, signalling a softer requirement, although Parties are ‘strongly encouraged’ to provide this information ( [[#UNFCCC--2019b|UNFCCC 2019b]] , Annex I, para. 9).

Parties’ first NDCs submitted to the provisional registry maintained by the UNFCCC Secretariat vary in terms of target type, reference year or points, timeframes, and scope and coverage of GHGs. A significant number of NDCs include adaptation, and several NDCs have conditional components, for instance, being conditional on the use of market mechanisms or on the availability of support ( [[#UNFCCC--2016b|UNFCCC 2016b]] ). There are wide variations across NDCs. Uncertainties are generated through interpretative ambiguities in the assumptions underlying NDCs ( [[#Rogelj--2017|Rogelj et al. 2017]] ). According to the assessment in this report, current policies lead to median global GHG emissions of 63 gigatonnes of CO 2 equivalent (GtCO 2 -eq), with a full range of 57–70 by 2030 and unconditional and conditional NDCs to 59 (55–65) and 56 (52–61) GtCO 2 -eq, respectively (Table 4.1). Many omit important mitigation sectors, provide little detail on financing implementation, and are not effective in meeting assessment and review needs ( [[#Pauw--2018|Pauw et al. 2018]] ). Although, it is estimated that the land use sector could contribute as much as 20% of the full mitigation potential of all the intended NDC targets ( [[#Forsell--2016|Forsell et al. 2016]] ), there are variations in how the land use component is included, and the related information provided, leading to large uncertainties on whether and how these will contribute to the achievement of the NDCs ( [[#Forsell--2016|Forsell et al. 2016]] ; [[#Grassi--2017|Grassi et al. 2017]] ; [[#Obergassel--2017a|Obergassel et al. 2017a]] ; [[#Benveniste--2018|Benveniste et al. 2018]] ; [[#Fyson--2019|Fyson and Jeffery 2019]] ). All these variations make it challenging to aggregate the efforts of countries and compare them to each other ( [[#Carraro--2016|Carraro 2016]] ). Although Parties attempted to discipline the variation in NDCs, including whether they could be conditional, through elaborating the ‘features’ of NDCs in the Rulebook, no agreement was possible on this. Thus, Parties continue to enjoy considerable discretion in the formulation of NDCs ( [[#Rajamani--2019|Rajamani and Bodansky 2019]] ; [[#Weikmans--2020|Weikmans et al. 2020]] ).

There are several approaches to evaluating NDCs, incorporating indicators such as CO 2 emissions, GDP, energy intensity of GDP, CO 2 per energy unit, CO 2 intensity of fossil fuels, and share of fossil fuels in total energy use ( [[#Peters--2017|Peters et al. 2017]] ). However, some favour approaches that use metrics beyond emissions such as infrastructure investment, energy demand, or installed power capacity ( [[#Iyer--2017|Iyer et al. 2017]] ; [[#Jeffery--2018|Jeffery et al. 2018]] ). One approach is to combine the comparison of aggregate NDC emissions using Integrated Assessment Model scenarios with modelling of NDC scenarios directly, and carbon budget analyses ( [[#Jeffery--2018|Jeffery et al. 2018]] ). Another approach is to engage in a comprehensive assessment of multiple indicators that reflect the different viewpoints of the Parties to the UNFCCC ( [[#Aldy--2017|Aldy et al. 2017]] ; [[#Höhne--2018|Höhne et al. 2018]] ). These different approaches are described in greater depth in Section 4.2.2.

It is clear, however, that the NDCs communicated by Parties for the 2020–2030 period are insufficient to achieve the temperature goal ( [[#den%20Elzen--2016|den Elzen et al. 2016]] ; Rogelj et al. 2016; [[#Schleussner--2016|Schleussner et al. 2016]] ; [[#Robiou%20du%20Pont--2018|Robiou du Pont and Meinshausen 2018]] ; [[#UNEP--2018a|UNEP 2018a]] ; [[#Alcaraz--2019|Alcaraz et al. 2019]] ; [[#UNEP--2019|UNEP 2019]] , 2020), and the emissions gap is larger than ever ( [[#Christensen--2019|Christensen and Olhoff 2019]] ) (Chapter 4). The IPCC ''Special Report on Global Warming of 1.5°C'' (SR1.5) notes that pathways that limit global warming to 1.5°C with no or limited overshoot show up to 40–50% reduction of total GHG emissions from 2010 levels by 2030, and that current pathways reflected in the NDCs are consistent with cost-effective pathways that result in a global warming of about 3°C by 2100 ( [[#IPCC--2018b|IPCC 2018b]] Summary for Policymakers D.1.1). Analysis by the UNFCCC Secretariat of the second round of those NDCs submitted by October 2021 suggests that ‘total global GHG emission level, taking into account full implementation of all the latest NDCs (including their conditional elements), implies possibility of global emissions peaking before 2030’. However, such total global GHG emission level in 2030 is still expected to be 15.9% above the 2010 level. This ‘implies an urgent need for either a significant increase in the level of ambition of NDCs between now and 2030 or a significant overachievement of the latest NDCs, or a combination of both.’ ( [[#UNFCCC--2021a|UNFCCC 2021a]] ).

Many NDCs with conditional elements may not be feasible as the conditions are not clearly defined and existing promises of support are insufficient ( [[#Pauw--2020|Pauw et al. 2020]] ). Moreover, ‘leadership by conditional commitments’ (when some states promise to take stronger commitments if others do so as well), and the system of pledge-and-review, may lead to decreasing rather than deeper contributions over time ( [[#Helland--2017|Helland et al. 2017]] ). Some note, however, that many of the NDCs are conservative and may be overachieved, that NDCs may be strengthened over time as expected under the Paris Agreement, and that there are significant non-state actions that have not been adequately captured in the NDCs ( [[#Höhne--2017|Höhne et al. 2017]] ). Further, if all NDCs with and without conditional elements are implemented, net land use, land use change and forestry emissions will decrease in 2030 compared to 2010 levels, but large uncertainties remain on how Parties estimate, project and account for emissions and removals from this sector ( [[#Forsell--2016|Forsell et al. 2016]] ; [[#Fyson--2019|Fyson and Jeffery 2019]] ). According to the estimates in Table 4.3, communicated unconditional commitments imply about a 7% reduction of world emissions by 2030, in terms of Kyoto GHGs, compared to a scenario where only current policies are in place. If conditional commitments are also included, the reduction in world emissions by 2030 would be about 12%.

In this context, it should be noted that many NDCs have been formulated with conditional elements, and such NDCs require international cooperation on finance, technology and capacity building ( [[#Kissinger--2019|Kissinger et al. 2019]] ), potentially including through Article 6 in the form of bilateral agreements and market mechanisms ( [[#UNFCCC--2016b|UNFCCC 2016b]] ). More broadly, some argue that there is a ‘policy inconsistency’ between the facilitative, ‘bottom up’ architecture of the Paris Agreement, and both the setting of the long-term temperature goal and expectations that it will be delivered ( [[#Geden--2016b|Geden 2016b]] ). As Figure 14.2 shows, there is a large share of additional effort needed to reach a 1.5°C compatible path by 2030 (and even a 2°C compatible path). International coordination and cooperation are crucial in enhancing the ambition of current pledges, as countries will be more willing to increase their ambition if matched by other countries (coordination) and if cost-minimising agreements between developed and developing countries, through Article 6 and other means, are fully developed (cooperation) ( [[#Sælen--2020|Sælen 2020]] ).

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[[File:0a9498e83eecdc130ce80f2eebb33e43 IPCC_AR6_WGIII_Figure_14_2.png]]

'''Figure 14.2 | The role of international cooperationin the reductions in annual emissions by 2030 needed to follow a 1.''' '''5°C (respectively &lt;2°C)''' '''cost-effective''' '''path from 2020 onwards.''' The figure represents the additional contribution of pledges included in the NDCs over current policies at the global level, and the remaining gap in emissions reductions needed to move from current policies to pathways that limit warning to 1.5°C (&gt;50%) with no or limited overshoot, and those to limit warming to 2°C (&gt;67%). Median values are used, showing the confidence interval for the total effort. See Figure 1 in Cross-Chapter Box 4 in Chapter 4, and Tables 4.2 and 4.3 for details. (i) The grey share represents NDCs with abatement efforts pledged without any conditions (called ‘unconditional’ in the literature). They are based mainly on domestic abatement actions, although countries can use international cooperation to meet their targets. (ii) The blue share represents NDCs with conditional components. They require international cooperation, for example bilateral agreements under Article 6, financing or monetary and/or technological transfers. (iii) The remaining gap in emissions reductions – the yellow share – can potentially be achieved through national and international actions. International coordination of more ambitious efforts promotes global ambition and international cooperation provides the cost-saving basis for more ambitious NDCs.

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<span id="ndcs-fairness-and-equity"></span>
==== 14.3.2.3 NDCs, Fairness and Equity ====

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The Paris Agreement encourages Parties, while submitting their NDCs, to explain how these are ‘fair and ambitious’ ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 4.8 read with [[#UNFCCC--2016a|UNFCCC 2016a]] , para. 27). The Rulebook obliges Parties to provide information on ‘fairness considerations, including reflecting on equity’ as applicable to their NDC ( [[#Rajamani--2019|Rajamani and Bodansky 2019]] ; [[#UNFCCC--2019b|UNFCCC 2019b]] paras. 7a and 9, Annex, paras. 6(a) and (b)). Although equity within nations and between communities is also important, much of the literature on fairness and equity in the context of NDCs focuses on equity between nations.

In the first round of NDCs, most Parties declared their NDCs as fair ( [[#Robiou%20du%20Pont--2017|Robiou du Pont et al. 2017]] ). Their claims, however, were largely unsubstantiated or drawn from analysis by in-country experts ( [[#Winkler--2018|Winkler et al. 2018]] ). At least some of the indicators Parties have identified in their NDCs as justifying the ‘fairness’ of their contributions, such as a ‘small share of global emissions’, ‘cost-effectiveness’ and assumptions that privilege current emissions levels (‘grandfathering’) are not, according to one group of scholars, in accordance with principles of international environmental law ( [[#Rajamani--2021|Rajamani et al. 2021]] ). Moreover, the NDCs reveal long-standing institutional divisions and divergent climate priorities between Annex I and non-Annex I Parties, suggesting that equity and fairness concerns remain salient ( [[#Stephenson--2019|Stephenson et al. 2019]] ). Fairness concerns also affect the share of CDR responsibilities for major emitters if they delay near-term mitigation action ( [[#Fyson--2020|Fyson et al. 2020]] ).

It is challenging, however, to determine ‘fair shares’, and address fairness and equity in a world of voluntary climate contributions ( [[#Chan--2016a|Chan 2016a]] ), in particular, since these contributions are insufficient ( [[#14.3.2.2|Section 14.3.2.2]] .). Self-differentiation in contributions has also led to fairness and equity being discussed in terms of individual Nationally Determined Contributions rather than between categories of countries ( [[#Chan--2016a|Chan 2016a]] ). In the climate change regime, one option is for Parties to provide more rigorous information under the Paris Agreement to assess fair shares ( [[#Winkler--2018|Winkler et al. 2018]] ), and another is for Parties to articulate what equity principles they have adopted in determining their NDCs and how they have operationalised these principles, and to explain their mitigation targets in terms of the portion of the appropriated global carbon budget ( [[#Hales--2018|Hales and Mackey 2018]] ).

Equity is critical to addressing climate change, including through the Paris Agreement ( [[#Klinsky--2017|Klinsky et al. 2017]] ), however, since the political feasibility of developing equity principles within the climate change regime is low, the onus is on mechanisms and actors outside the regime to develop these ( [[#Lawrence--2019|Lawrence and Reder 2019]] ). Equity and fairness concerns are being raised in national and regional courts that are increasingly being asked to determine if the climate actions pledged by states are adequate in relation to their fair share ( [[#The%20Supreme%20Court%20of%20the%20Netherlands--2019|The Supreme Court of the Netherlands 2019]] ; [[#European%20Court%20of%20Human%20Rights--2020|European Court of Human Rights 2020]] ; German Constitutional Court 2021), as it is only in relation to such a ‘fair share’ that the adequacy of a state’s contribution can be assessed in the context of a global collective action problem ( [[IPCC:Wg3:Chapter:Chapter-13#13.5|Section 13.5]] .5). Some domestic courts have stressed that as climate change is a global problem of cumulative impact, all emissions contribute to the problem regardless of their relative size and there is a clear articulation under the UNFCCC and Paris Agreement for developed countries to ‘take the lead’ in addressing GHG emissions ( [[#Preston--2020|Preston 2020]] ). Given the limited avenues for multilateral determination of fairness, several researchers have argued that the onus is on the scientific community to generate methods to assess fairness ( [[#Herrala--2016|Herrala and Goel 2016]] ; [[#Lawrence--2019|Lawrence and Reder 2019]] ). Peer-to-peer comparisons also potentially create pressure for ambitious NDCs ( [[#Aldy--2017|Aldy et al. 2017]] ).

There are a range of options to assess or introduce fairness. These include: adopting differentiation in financing rather than in mitigation ( [[#Gajevic%20Sayegh--2017|Gajevic Sayegh 2017]] ); adopting a carbon budget approach ( [[#Hales--2018|Hales and Mackey 2018]] ; [[#Alcaraz--2019|Alcaraz et al. 2019]] ), which may occur through the transparency processes ( [[#Hales--2018|Hales and Mackey 2018]] ); quantifying national emissions allocations using different equity approaches, including those reconciling finance and emissions rights distributions ( [[#Robiou%20du%20Pont--2017|Robiou du Pont et al. 2017]] ); combining equity concepts in a bottom-up manner using different sovereign approaches ( [[#Robiou%20du%20Pont--2018|Robiou du Pont and Meinshausen 2018]] ), using data on adopted emissions targets to find an ethical framework consistent with the observed distribution ( [[#Sheriff--2019|Sheriff 2019]] ); adopting common metrics for policy assessment ( [[#Bretschger--2017|Bretschger 2017]] ); and developing a template for organising metrics on mitigation effort – emissions reductions, implicit prices, and costs – for both ''ex-ante'' and ''ex-post'' review ( [[#Aldy--2017|Aldy et al. 2017]] ). The burden of agricultural mitigation can also be distributed using different approaches from effort sharing (responsibility, capability, need, equal cumulative per-capita emissions) ( [[#Richards--2018|Richards et al. 2018]] ). Further, there are temporal (inter-generational) and spatial (inter-regional) dimensions to the distribution of the mitigation burden, with additional emissions reductions in 2030 improving both inter-generational and inter-regional equity ( [[#Liu--2016|Liu et al. 2016]] ). Some of the equity approaches rely on ‘grandfathering’ as an allocation principle, which some argue has led to ‘cascading biases’ against developing countries ( [[#Kartha--2018|Kartha et al. 2018]] ), and is morally ‘perverse’ ( [[#Caney--2011|Caney 2011]] ). While no country’s NDC explicitly supports the grandfathering approach, many countries describe as ‘fair and ambitious’ NDCs that assume grandfathering as the starting point ( [[#Robiou%20du%20Pont--2017|Robiou du Pont et al. 2017]] ). It is worth noting that the existence of multiple metrics associated with a range of equity approaches has implications for how the ambition and ‘fair’ share of each state is arrived at; some average out multiple approaches and indicators ( [[#Hof--2012|Hof et al. 2012]] ; Meinshausen et al. 2015; [[#Robiou%20du%20Pont--2018|Robiou du Pont and Meinshausen 2018]] ), others exclude indicators and approaches that do not, in their interpretation, accord with principles of international environmental law ( [[#Rajamani--2021|Rajamani et al. 2021]] ). One group of scholars has suggested that utilitarianism offers an ‘ethically minimal and conceptually parsimonious’ benchmark that promotes equity, climate and development ( [[#Budolfson--2021|Budolfson et al. 2021]] ).

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<span id="transparency-and-accountability"></span>
==== 14.3.2.4 Transparency and Accountability ====

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Although NDCs reflect a ‘bottom-up’, self-differentiated approach to climate mitigation actions, the Paris Agreement couples this to an international transparency framework designed, among other things, to track progress in implementing and achieving mitigation contributions ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 13). This transparency framework builds on the processes that already exist under the UNFCCC. The transparency framework under the Paris Agreement is applicable to all Parties, although with flexibilities for developing country Parties that need it in light of their capacities ( [[#Mayer--2019|Mayer 2019]] ). Each Party is required to submit a national inventory report, as well as ‘the information necessary to track progress in implementing and achieving’ its NDC ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 13.7) biennially ( [[#UNFCCC--2016a|UNFCCC 2016a]] , para. 90). The Paris Rulebook requires all Parties to submit their national inventory reports using the 2006 IPCC Guidelines ( [[#UNFCCC--2019b|UNFCCC 2019b]] , Annex, para. 20).

In relation to the provision of information necessary to track progress towards implementation and achievement of NDCs, the Paris Rulebook allows each Party to choose its own qualitative or quantitative indicators ( [[#UNFCCC--2019k|UNFCCC 2019k]] , Annex, para. 65), a significant concession to national sovereignty ( [[#Rajamani--2019|Rajamani and Bodansky 2019]] ). The Rulebook phases in common reporting requirements for developed and developing countries (except LDCs and SIDS) at the latest by 2024 ( [[#UNFCCC--2019k|UNFCCC 2019k]] , para. 3), but offers flexibilities in ‘scope, frequency, and level of detail of reporting, and in the scope of the review’ for those developing countries that need it in light of their capacities ( [[#UNFCCC--2019k|UNFCCC 2019k]] , Annex, para. 5). Some differentiation also remains for information on support provided to developing countries ( [[#Winkler--2017|Winkler et al. 2017]] ), with developed country Parties required to report such information biennially, while others are only ‘encouraged’ to do so ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 9.7).

The information provided by Parties in biennial transparency reports and GHG inventories will undergo technical expert review, which must include assistance in identifying capacity-building needs for developing country Parties that need it in light of their capacities. Each Party is also required to participate in a ‘facilitative, multilateral consideration of progress’ of implementation and achievement of its NDC. Although the aim of these processes is to expose each Party’s actions on mitigation to international review, thus establishing a weak form of accountability for NDCs at the international level, the Rulebook circumscribes the reach of these processes ( [[#Rajamani--2019|Rajamani and Bodansky 2019]] ). The technical expert review teams are prohibited in mandatory terms from making ‘political judgments’ or reviewing the ‘adequacy or appropriateness’ of a Party’s NDC, domestic actions, or support provided ( [[#UNFCCC--2019k|UNFCCC 2019k]] , Annex, para. 149). This, among other such provisions, has led some to argue that the scope and practice of existing transparency arrangements reflect rather than mediate ongoing disputes around responsibility, differentiation and burden sharing, and thus there is limited answerability through transparency ( [[#Gupta--2019|Gupta and van Asselt 2019]] ). There are also limits to the extent that the enhanced transparency framework will reduce ambiguities and associated uncertainties, for instance, in how land use, land-use change and forestry (LULUCF) are incorporated into the NDCs ( [[#Fyson--2019|Fyson and Jeffery 2019]] ), and lead to increased ambition ( [[#Weikmans--2020|Weikmans et al. 2020]] ). More broadly, there has been ‘weak’ translation of transparency norms into accountability ( [[#Ciplet--2018|Ciplet et al. 2018]] ). Hence, the Paris Agreement’s effectiveness in ensuring NDCs are achieved will depend on additional accountability pathways at the domestic level involving political processes and civil society engagement ( [[#Jacquet--2016|Jacquet and Jamieson 2016]] ; [[#van%20Asselt--2016|van Asselt 2016]] ; [[#Campbell-Duruflé--2018a|Campbell-Duruflé 2018a]] ; [[#Karlsson-Vinkhuyzen--2018|Karlsson-Vinkhuyzen et al. 2018]] ).

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<span id="global-stocktake"></span>
==== 14.3.2.5 Global Stocktake ====

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The Paris Agreement’s transparency framework is complemented by the global stocktake, which will take place every five years (starting in 2023) and assess the collective progress towards achieving the Agreement’s purpose and long-term goals ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 14). The scope of the global stocktake is comprehensive – covering mitigation, adaptation and means of implementation and support – and the process is to be facilitative and consultative. The Paris Rulebook outlines the scope of the global stocktake to include social and economic consequences and impacts of response measures, and loss and damage associated with the adverse effects of climate change ( [[#UNFCCC--2019f|UNFCCC 2019f]] , paras. 8–10).

The global stocktake is to occur ‘in the light of equity and the best available science’. While the focus of the global stocktake is on collective and not individual progress towards the goals of the Agreement, the inclusion of equity in the global stocktake enables a discussion on equitable burden sharing ( [[#Rajamani--2016a|Rajamani 2016a]] ; [[#Winkler--2020|Winkler 2020]] ), and for equity metrics to be factored in ( [[#Robiou%20du%20Pont--2018|Robiou du Pont and Meinshausen 2018]] ). The Paris Rulebook includes consideration of the modalities and sources of inputs for the global stocktake ( [[#UNFCCC--2019f|UNFCCC 2019f]] , paras. 1, 2, 13, 27, 31, 36h and 37g), which arguably will result in equity being factored into the outcome of the stocktake ( [[#Winkler--2020|Winkler 2020]] ). The Rulebook does not, however, some argue, resolve the tension between the collective nature of the assessment that is authorised by the stocktake and the individual assessments required to determine relative ‘fair share’ ( [[#Rajamani--2019|Rajamani and Bodansky 2019]] ; [[#Zahar--2019|Zahar 2019]] ).

The global stocktake is seen as crucial to encouraging Parties to increase the ambition of their NDCs ( [[#Huang--2018|Huang 2018]] ; [[#Hermwille--2019|Hermwille et al. 2019]] ; [[#Milkoreit--2019|Milkoreit and Haapala 2019]] ) as its outcome ‘shall inform Parties in updating and enhancing, in a nationally determined manner, their actions and support’ (Art. 14.3) (Rajamani 2016a; [[#Friedrich--2017|Friedrich 2017]] ; [[#Zahar--2019|Zahar 2019]] ). The Rulebook provides for the stocktake to draw on a wide variety of inputs sourced from a full range of actors, including ‘non-Party stakeholders’ ( [[#UNFCCC--2019f|UNFCCC 2019f]] , para. 37). However, the Rulebook specifies that the global stocktake will be ‘a Party-driven process’ ( [[#UNFCCC--2019f|UNFCCC 2019f]] , para. 10), will not have an ‘individual Party focus’, and will include only ‘non-policy prescriptive consideration of collective progress’ ( [[#UNFCCC--2019f|UNFCCC 2019f]] , para. 14).

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==== 14.3.2.6 Conservation of Sinks and Reservoirs, Including Forests ====

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Article 5 of the Paris Agreement calls for Parties to take action to conserve and enhance sinks and reservoirs of greenhouse gases, including biomass in terrestrial, coastal, and marine ecosystems, and encourages countries to take action to support the REDD+ framework under the Convention. The explicit inclusion of land use sector activities, including forest conservation, is potentially, while cautiously, a ‘game changer’ as it encourages countries to safeguard ecosystems for climate mitigation purposes ( [[#Grassi--2017|Grassi et al. 2017]] ). Analyses of Parties’ NDCs shows pledged mitigation from land use, and forests in particular, provides a quarter of the emissions reductions planned by Parties and, if fully implemented, would result in forests becoming a net sink of carbon by 2030 ( [[#Forsell--2016|Forsell et al. 2016]] ; [[#Grassi--2017|Grassi et al. 2017]] ).

A key action endorsed by Article 5 is REDD+, which refers to initiatives established under the UNFCCC for reducing emissions from deforestation and forest degradation and the role of conservation, sustainable management of forests and enhancement of forest carbon stocks in developing countries. It remains an evolving concept and some identified weaknesses are being addressed, including the issues of scale (project-based vs sub-national jurisdictional approach), problems with leakage, reversal, and benefit sharing, as well as safeguards against potential impacts on local and indigenous communities. Nevertheless, REDD+ shows several innovations under the climate regime with regard to international cooperation. The legal system for REDD+ manages to reconcile flexibility (creating consensus) and legal security. It shows a high standard of effectiveness ( [[#Dellaux--2017|Dellaux 2017]] ).

Article 5.2 encourages Parties to implement and support the existing framework for REDD+, including through ‘results-based payments’, that is provision of financial payments for verified avoided or reduced forest carbon emissions ( [[#Turnhout--2017|Turnhout et al. 2017]] ). The existing REDD+ framework set up under decisions of the UNFCCC COP includes the Warsaw Framework for REDD+, which specifies modalities for measuring, reporting and verifying greenhouse gas emissions and removals. This provides an essential tool for linking REDD+ activities to results-based finance ( [[#Voigt--2015|Voigt and Ferreira 2015]] ). Appropriate finance support for REDD+ is also considered critical to move from its inclusion in many countries’ NDCs to implementation on the ground ( [[#Hein--2018|Hein et al. 2018]] ). Since public finance for REDD+ is limited, private sector participation is expected by some to leverage REDD+ ( [[#Streck--2012|Streck and Parker 2012]] ; [[#Henderson--2013|Henderson et al. 2013]] ; [[#Pistorius--2015|Pistorius and Kiff 2015]] ; [[#Seymour--2016|Seymour and Busch 2016]] ; [[#Ehara--2019|Ehara et al. 2019]] ). Article 5.2 also encourages Parties’ support for ‘alternative policy approaches’ to forest conservation and sustainable management such as ‘joint mitigation and adaptation approaches’. It reaffirms the importance of incentivising, as appropriate, non-carbon benefits associated with such approaches (e.g., improvements in the livelihoods of forest‐dependent communities, facilitating poverty reduction and sustainable development). This provision, along with the support for non-market mechanisms in Article 6 (discussed below), is seen as an avenue for cooperative joint mitigation–adaptation and non-market REDD+ activities with co-benefits for biodiversity conservation ( [[#Gupta--2018|Gupta and Dube 2018]] ).

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<span id="cooperative-approaches"></span>
==== 14.3.2.7 Cooperative Approaches ====

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Article 6 of the Paris Agreement provides for voluntary cooperative approaches. Its potential importance in terms of project-based cooperation should be viewed against the background of key lessons from the market-based mechanisms under the Kyoto Protocol, particularly the Clean Development Mechanism (CDM). The CDM has been used for implementing bilateral strategies and unilateral (non-market) actions for instance in India ( [[#Phillips--2013|Phillips and Newell 2013]] ), hence arguably covering all the mechanisms now included in Article 6 of the Paris Agreement. As we describe in [[#14.3.3.1|Section 14.3.3.1]] , below, ''ex post'' evaluation of the Kyoto market mechanisms, in particular the CDM, have been at best mixed. However, Article 6 goes beyond the project-based approach followed by the CDM, as hinted by the emerging landscape of activities based on Article 6 ( [[#Greiner--2020|Greiner et al. 2020]] ), such as the bilateral treaty signed under the framework of Article 6 in October 2020 by Switzerland and Peru ( [[#14.4.4|Section 14.4.4]] ).

This experience from the CDM is relevant to the implementation of Article 6 (4) of the Paris Agreement. It addresses a number of specific types of cooperative approaches, including those involving the use of internationally transferred mitigation outcomes (ITMOs) towards NDCs, a ‘mechanism to contribute to mitigation and support sustainable development’, and a framework for non-market approaches such as many aspects of REDD+.

Article 6.1 recognises the role that cooperative approaches can play, on a voluntary basis, in implementing Parties’ NDCs ‘in order to allow for higher ambition’ in their mitigation actions and to promote sustainable development and environmental integrity. Article 6.2 indicates that ITMOs can originate from a variety of sources, and that Parties using ITMOs to achieve their NDCs shall promote sustainable development, ensure environmental integrity, ensure transparency, including in governance, and apply ‘robust accounting’ in accordance with Conference of the Parties serving as the Meeting of the Parties to the Paris Agreement (CMA) guidance to prevent double counting. While this provision, unlike Article 17 of the Kyoto Protocol, does not create an international carbon market, it enables Parties to pursue this option should they choose to do so, for example, through the linking of domestic or regional carbon markets ( [[#Marcu--2016|Marcu 2016]] ; [[#Müller--2019|Müller and Michaelowa 2019]] ). Article 6.2 could also be implemented in other ways, including direct transfers between governments, linkage of mitigation policies across two or more Parties, sectoral or activity crediting mechanisms, and other forms of cooperation involving public or private entities, or both ( [[#Howard--2017|Howard 2017]] ).

Assessments of the potential of Article 6.2 generally find that ITMOs are likely to result in cost reductions in achieving mitigation outcomes, with the potential for such reductions to enhance ambition and accelerate Parties’ progression of mitigation pledges across NDC cycles ( [[#Fujimori--2016|Fujimori et al. 2016]] ; [[#Gao--2016|Gao et al. 2016]] ; [[#Mehling--2019|Mehling 2019]] ). However, studies applying insights from the CDM highlight environmental integrity risks associated with using ITMOs under the Paris Agreement given the challenges that the diverse scope, metrics, types and timeframes of NDC targets pose for robust accounting ( [[#Schneider--2019|Schneider and La Hoz Theuer 2019]] ) and the potential for transfers of ‘hot air’, as occurred under the Kyoto Protocol ( [[#La%20Hoz%20Theuer--2019|La Hoz Theuer et al. 2019]] ). These studies collectively affirm that robust governance on accounting for ITMOs, and for reporting and review, will be critical to ensuring the environmental integrity of NDCs making use of them ( [[#Mehling--2019|Mehling 2019]] ; [[#Müller--2019|Müller and Michaelowa 2019]] ).

Article 6.4 concerns the mitigation mechanism, with some similarities to the Kyoto Protocol’s CDM. Unlike the CDM, there is no restriction on which Parties can host mitigation projects and which Parties can use the resulting emissions reductions towards their NDCs ( [[#Marcu--2016|Marcu 2016]] ). This central mechanism will operate under the authority and guidance of the CMA, and is to be supervised by a body designated by the CMA ( [[#Marcu--2016|Marcu 2016]] ).

The Article 6.4 central mechanism is intended to promote mitigation while fostering sustainable development. The decision adopting the Paris Agreement specifies experience with Kyoto market mechanisms as a basis for the new mitigation mechanism ( [[#UNFCCC--2016a|UNFCCC 2016a]] , para. 37(f)). Compared with the CDM under the Kyoto Protocol, the central mechanism has a more balanced focus on both climate and development objectives, and a stronger political mandate to measure sustainable development impact and to verify that the impacts are ‘real, measurable, and long-term’ ( [[#Olsen--2018|Olsen et al. 2018]] ). There are also opportunities to integrate human rights into the central mechanism ( [[#Obergassel--2017b|Obergassel et al. 2017b]] ; [[#Calzadilla--2018|Calzadilla 2018]] ). It is further subject to the requirement that it must deliver ‘an overall mitigation in global emissions’, which is framed by the general objectives of Article 6 for cooperation to enhance ambition ( [[#Kreibich--2018|Kreibich 2018]] ).

Negotiations over rules to operationalise Article 6 have thus far proven intractable, failing to deliver both at COP24 in Katowice in 2018, where the rest of the Paris Rulebook was agreed, and in COP25 in Madrid in 2019. Ongoing points of negotiation have included: whether to permit the carryover and use of Kyoto CDM credits and assigned amount units into the Article 6.4 mechanism, whether to impose a mandatory share of proceeds on Article 6.2 mechanism to fund adaptation, like for Article 6.4; and whether and how credits generated under Article 6.4 should be subject to accounting rules under Article 6.2 ( [[#Michaelowa--2020a|Michaelowa et al. 2020a]] ).

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<span id="finance-flows"></span>
==== 14.3.2.8 Finance Flows ====

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Finance is the first of three means of support specified under the Paris Agreement to accomplish its objectives relating to mitigation (and adaptation) ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 14.1). This sub-section discusses the provision made in the Paris Agreement for international cooperation on finance. [[#14.4.1|Section 14.4.1]] below considers broader cooperative efforts on public and private finance flows for climate mitigation, including by multilateral development banks and through instruments such as green bonds.

As highlighted above, the objective of the Paris Agreement includes the goal of ‘[m]aking finance flows consistent with a pathway towards low greenhouse gas emissions and climate-resilient development’ ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 2.1(c)). Alignment of financial flows, and in some cases provision of finance, will be critical to the achievement of many Parties’ NDCs, particularly those that are framed in conditional terms ( [[#Zhang--2016|Zhang and Pan 2016]] ; [[#Kissinger--2019|Kissinger et al. 2019]] ) (Chapter 15).

International cooperation on climate finance represents ‘a complex and fragmented landscape’ with a range of different mechanisms and forums involved ( [[#Pickering--2017|Pickering et al. 2017]] ; [[#Roberts--2017|Roberts and Weikmans 2017]] ). These include entities set up under the international climate change regime, such as the UNFCCC financial mechanism, with the Global Environment Facility (GEF) and Green Climate Fund (GCF) as operating entities; special funds, such as the Special Climate Change Fund, the Least Developed Countries Fund (both managed by the GEF), and the Adaptation Fund established under the Kyoto Protocol; the Standing Committee on Finance, a constituted body which assists the COP in exercising its functions with respect to the UNFCCC financial mechanism; and other bodies outside of the international climate change regime, such as the Climate Investment Funds administered through multilateral development banks (the role of these banks in climate finance is discussed further in [[#14.4.1|Section 14.4.1]] below).

Pursuant to decisions adopted at the Paris and Katowice conferences, Parties agreed that the operating entities of the financial mechanism – GEF and GCF – as well as the Special Climate Change Fund, the Least Developed Countries Fund, the Adaptation Fund and the Standing Committee on Finance, all serve the Paris Agreement ( [[#UNFCCC--2016a|UNFCCC 2016a]] , paras. 58 and 63, 2019e,g). The GCF, which became operational in 2015, is the largest dedicated international climate change fund and plays a key role in channelling financial resources to developing countries ( [[#Antimiani--2017|Antimiani et al. 2017]] ; [[#Brechin--2017|Brechin and Espinoza 2017]] ).

Much of the current literature on climate finance and the Paris Agreement focuses on the obligations of developed countries to provide climate finance to assist the implementation of mitigation and adaptation actions by developing countries. The principal provision on finance in the Paris Agreement is the binding obligation on developed country Parties to provide financial resources to assist developing country Parties ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 9.1). This provision applies to both mitigation and adaptation and is in continuation of existing developed country Parties’ obligations under the UNFCCC. This signals that the Paris Agreement finance requirements must be interpreted in light of the UNFCCC ( [[#Yamineva--2016|Yamineva 2016]] ). The novelty introduced by the Paris Agreement is a further expansion in the potential pool of donor countries as Article 9.2 encourages ‘other Parties’ to provide or continue to provide such support on a voluntary basis. However, ‘as part of the global effort, developed countries should continue to take the lead in mobilising climate finance’, with a ‘significant role’ for public funds, and an expectation that such mobilisation of finance ‘should represent a progression beyond previous efforts’. Beyond this, there are no new recognised promises ( [[#Ciplet--2018|Ciplet et al. 2018]] ). In the Paris Agreement, Parties formalised the continuation of the existing collective mobilisation goal to raise USD100 billion yr –1 through to 2025 in the context of meaningful mitigation actions and transparency on implementation. The Paris Agreement decision also provided for the CMA by 2025 to set a new collective quantified goal from a floor of USD100 billion yr –1 , taking into account the needs and priorities of developing countries ( [[#UNFCCC--2016a|UNFCCC 2016a]] , para. 53). This new collective goal on finance is not explicitly limited to developed countries and could therefore encompass finance flows from developing countries’ donors ( [[#Bodansky--2017b|Bodansky et al. 2017b]] ). Deliberations on setting a new collective quantified goal on finance is expected to be initiated at COP26 in 2021 ( [[#UNFCCC--2019g|UNFCCC 2019g]] ,e; [[#Zhang--2019|Zhang 2019]] ).

It is widely recognised that the USD100 billion yr –1 figure is a fraction of the broader finance and investment needs of mitigation and adaptation embodied in the Paris Agreement ( [[#Peake--2017|Peake and Ekins 2017]] ). One estimate, based on a review of 160 Intended Nationally Determined Contributions ((I)NDCs), suggests the financial demand for both mitigation and adaptation needs of developing countries could reach USD474 billion yr –1 by 2030 ( [[#Zhang--2016|Zhang and Pan 2016]] ). The Organisation for Economic Co-operation and Development (OECD) reports that climate finance provided and mobilised by developed countries was USD79.6 billion in 2019. This finance included four components: bilateral public, multilateral public (attributed to developed countries), officially supported export credits and mobilised private finance ( [[#OECD--2021|OECD 2021]] ) ( [[IPCC:Wg3:Chapter:Chapter-15#15.3.2|Section 15.3.2]] and Box 15.4).

More broadly, there is recognition of the need for better accounting, transparency and reporting rules to allow evaluation of the fulfilment of finance pledges and the effectiveness of how funding is used ( [[#Xu--2016|Xu et al. 2016]] ; [[#Roberts--2017|Roberts et al. 2017]] ; [[#Jachnik--2019|Jachnik et al. 2019]] ; [[#Gupta--2019|Gupta and van Asselt 2019]] ; [[#Roberts--2021|Roberts et al. 2021]] ). There is also a concern about climate finance being new and additional though the Paris Agreement does not make an explicit reference to it, nor is there a clear understanding of what constitutes new and additional ( [[#UNFCCC--2018|UNFCCC 2018]] ; [[#Carty--2020|Carty et al. 2020]] ; [[#Mitchell--2021|Mitchell et al. 2021]] ). Some authors see the ‘enhanced transparency framework’ of the Paris Agreement ( [[#14.3.2.4|Section 14.3.2.4]] ), and the specific requirements for developed countries to provide, biennially, indicative quantitative and qualitative information as well as report on financial support and mobilisation efforts (Articles 9.5 and 9.7), as promising marked improvements ( [[#Weikmans--2019|Weikmans and Roberts 2019]] ), including for the fairness of effort-sharing on climate finance provision ( [[#Pickering--2015|Pickering et al. 2015]] ). Others offer a more circumspect view of the transformative capability of these transparency systems ( [[#Ciplet--2018|Ciplet et al. 2018]] ).

The more limited literature focusing on the specific finance needs of developing countries, particularly those expressed in NDCs conditional on international climate finance, suggests that once all countries have fully costed their NDCs, the demand for (public and private) finance to support NDC implementation is likely to be orders of magnitude larger than funds available from bilateral and multilateral sources. For some sectors, such as forestry and land use, this could leave ‘NDC ambitions... in a precarious position, unless more diversified options are pursued to reach climate goals’ ( [[#Kissinger--2019|Kissinger et al. 2019]] ). In addition, there is a need for fiscal policy reform in developing countries to ensure international climate finance flows are not undercut by public and private finance supporting unsustainable activities ( [[#Kissinger--2019|Kissinger et al. 2019]] ). During the 2018 Katowice conference, UNFCCC Parties requested the Standing Committee on Finance to prepare, every four years, a report on the determination of the needs of developing country Parties related to implementing the Convention and the Paris Agreement, for consideration by Parties at COP26 ( [[#UNFCCC--2019c|UNFCCC 2019c]] ).

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<span id="technology-development-and-transfer"></span>
==== 14.3.2.9 Technology Development and Transfer ====

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Technology development and transfer is the second of three ‘means of implementation and support’ specified under the Paris Agreement to accomplish its objectives relating to mitigation (and adaptation) ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 14.1). This sub-section discusses the provision made in the Paris Agreement for international cooperation on technology development and transfer. [[#14.4.2|Section 14.4.2]] below considers broader cooperative efforts on technology development and transfer under the UNFCCC. Both sections complement the discussion in [[IPCC:Wg3:Chapter:Chapter-16#16.6|Section 16.6]] on the role of international cooperation in fostering transformative change.

The importance of technology as a means of implementation for climate mitigation obligations under the Paris Agreement is evident from Parties’ NDCs. Of the 168 NDCs submitted as of June 2019, 109 were expressed as conditional upon support for technology development and transfer, with 70 Parties requesting technological support for both mitigation and adaptation, and 37 Parties for mitigation only ( [[#Pauw--2020|Pauw et al. 2020]] ). Thirty-eight LDCs (79%) and 29 SIDS made their NDCs conditional on technology transfer, as did 50 middle-income countries ( [[#Pauw--2020|Pauw et al. 2020]] ).

While technology is seen as a key means of implementation and support for Paris Agreement commitments, the issue of technology development and the transfer of environmentally sound technologies for climate mitigation was heavily contested between developed and developing countries in the Paris negotiations, and these differences are likely to persist as the Paris Agreement is implemented ( [[#Oh--2019|Oh 2019]] ). Contestations continued in negotiations for the Paris Rulebook, particularly regarding the meaning of technological innovation, which actors should be supported, and how support should be provided by the UNFCCC ( [[#Oh--2020a|Oh 2020a]] ).

Article 10 of the Paris Agreement articulates a shared ‘long-term vision on the importance of fully realising technology development and transfer in order to improve resilience to climate change and to reduce greenhouse gas emissions’ (UNFCCC 2015, Art. 10.1). All Parties are required ‘to strengthen cooperative action on technology development and transfer’ (UNFCCC 2015, Art. 10.2). In addition, support, including financial support, ‘shall be provided’ to developing country Parties for the implementation of Article 10, ‘including for strengthening cooperative action on technology development and transfer at different stages of the technology cycle, with a view to achieving a balance between support for mitigation and adaptation’ (UNFCCC 2015, Art. 10.6). Available information on efforts related to support on technology development and transfer for developing country Parties is also one of the matters to be taken into account in the global stocktake (UNFCCC 2015, Art. 10.6) ( [[#14.3.2.5|Section 14.3.2.5]] ).

The Paris Agreement emphasises that efforts to accelerate, encourage and enable innovation are ‘critical for an effective long-term global response to climate change and promoting economic growth and sustainable development’ and urges that they be supported, as appropriate, by the Technology Mechanism and Financial Mechanism of the UNFCCC (UNFCCC 2015, Art. 10.5). This support should be directed to developing country Parties ‘for collaborative approaches to research and development, and facilitating access to technology, in particular for early stages of the technology cycle’ (UNFCCC 2015, Art. 10.5). Inadequate support for research and development, particularly in developing countries, has been identified in previous studies of technology interventions by international institutions as a key technology innovation gap that might be addressed by the Technology Mechanism ( [[#de%20Coninck--2015|de Coninck and Puig 2015]] ).

To support Parties’ cooperative action, the Technology Mechanism, established in 2010 under the UNFCCC ( [[#14.4.2|Section 14.4.2]] ), will serve the Paris Agreement, subject to guidance of a new ‘technology framework’ (UNFCCC 2015, Art. 10.4). The latter was strongly advocated by the African group in the negotiations for the Paris Agreement ( [[#Oh--2020a|Oh 2020a]] ), and was adopted in 2018 as part of the Paris Rulebook, with implementation entrusted to the component bodies of the Technology Mechanism. The guiding principles of the framework are coherence, inclusiveness, a results-oriented approach, a transformational approach and transparency. Its ‘key themes’ include innovation, implementation, enabling environment and capacity building, collaboration and stakeholder engagement, and support ( [[#UNFCCC--2019e|UNFCCC 2019e]] , Annex). A number of ‘actions and activities’ are elaborated for each thematic area. These include: enhancing engagement and collaboration with relevant stakeholders, including local communities and authorities, national planners, the private sector and civil society organisations, in the planning and implementation of Technology Mechanism activities; facilitating Parties undertaking, updating and implementing technology needs assessments (TNAs) and aligning these with NDCs; and enhancing the collaboration of the Technology Mechanism with the Financial Mechanism for enhanced support for technology development and transfer. As regards TNAs, while some developing countries have already used the results of their TNA process in NDC development, other countries might benefit from following the TNA process, including its stakeholder involvement and multi-criteria decision analysis methodology, to strengthen their NDCs (Hofman and van der Gaast 2019).

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<span id="capacity-building"></span>
==== 14.3.2.10 Capacity Building ====

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Together with finance, and technology development and transfer, capacity building is the third of ‘the means of implementation and support’ specified under the Paris Agreement ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 14.1). Capacity building has primarily been implemented through partnerships, collaboration and different cooperative activities, inside and outside the UNFCCC. This sub-section discusses the provision made in the Paris Agreement for international cooperation on capacity building. [[#14.4.3|Section 14.4.3]] below considers broader cooperative efforts on capacity building within the UNFCCC.

In its annual synthesis report for 2018, the UNFCCC secretariat stressed the importance of capacity building for the implementation of the Paris Agreement and NDCs, with a focus on measures already in place, regional and cooperative activities, and capacity-building needs for strengthening NDCs ( [[#UNFCCC--2019h|UNFCCC 2019h]] ). Of the 168 NDCs submitted as of June 2019, capacity building was the most frequently requested type of support (113 of 136 conditional NDCs) ( [[#Pauw--2020|Pauw et al. 2020]] ). The focus of capacity-building activities is on enabling developing countries to take effective climate change action, given that many developing countries continue to face significant capacity challenges, undermining their ability to effectively or fully carry out the climate actions they intend to pursue ( [[#Dagnet--2016|Dagnet et al. 2016]] ). Content analysis of NDCs shows that capacity building for adaptation is prioritised over mitigation for developing countries, with the element of capacity building most indicated in NDCs being research and technology ( [[#Khan--2020|Khan et al. 2020]] ). In addition, developing countries’ needs for education, training and awareness raising for climate change mitigation and adaptation feature prominently in NDCs, particularly those of LDCs ( [[#Khan--2020|Khan et al. 2020]] ). Differences are evident though between capacity-building needs expressed in the NDCs of LDCs (noting that Khan et al.s review was limited to NDCs in English) compared with those of upper-middle-income developing countries as categorised by the World Bank ( [[#World%20Bank--2021|World Bank 2021]] ); the latter have more focus on mitigation with an emphasis on technology development and transfer ( [[#Khan--2020|Khan et al. 2020]] ).

The Paris Agreement urges all Parties to cooperate to enhance the capacity of developing countries to implement the Agreement ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 11.3), with a particular focus on LDCs and SIDS ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 11.1). Developed country Parties are specifically urged to enhance support for capacity-building actions in developing country Parties ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 11.3). Article 12 of the Paris Agreement addresses cooperative measures to enhance climate change education, training, public awareness, public participation and public access to information, which can also be seen as elements of capacity building ( [[#Khan--2020|Khan et al. 2020]] ). Under the Paris Rulebook, efforts related to the implementation of Article 12 are referred to as ‘Action for Climate Empowerment’ and Parties are invited to develop and implement national strategies on this topic, taking into account their national circumstances ( [[#UNFCCC--2019i|UNFCCC 2019i]] , para. 6). Actions to enhance climate change education, training, public awareness, public participation, public access to information, and regional and international cooperation may also be taken into account by Parties in the global stocktake process under Article 14 of the Paris Agreement ( [[#UNFCCC--2019i|UNFCCC 2019i]] , para. 9).

Under the Paris Agreement, capacity-building can take a range of forms, including: facilitating technology development, dissemination and deployment; access to climate finance; education, training and public awareness; and the transparent, timely and accurate communication of information ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 11.1) ( [[#14.3.2.4|Section 14.3.2.4]] ). Principles guiding capacity-building support are that it should be: country-driven; based on and responsive to national needs; fostering country ownership of Parties at multiple levels; guided by lessons learned; and an effective, iterative process that is participatory, cross-cutting and gender-responsive ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 11.2). Parties undertaking capacity building for developing country Parties must ‘regularly communicate on these actions or measures’. Developing country Parties have a soft requirement (‘should’) to communicate progress made on implementing capacity-building plans, policies, actions or measures to implement the Paris Agreement ( [[#UNFCCC--2015a|UNFCCC 2015a]] , Art. 11.4).

Article 11.5 provides that capacity-building activities ‘shall be enhanced through appropriate institutional arrangements to support the implementation of this Agreement, including the appropriate institutional arrangements established under the Convention that serve this Agreement’. The COP decision accompanying the Paris Agreement established the Paris Committee on Capacity-building, with the aim to ‘address gaps and needs, both current and emerging, in implementing capacity-building in developing country Parties and further enhancing capacity-building efforts, including with regard to coherence and coordination in capacity-building activities under the Convention’ ( [[#UNFCCC--2016a|UNFCCC 2016a]] , para. 71). The activities of the Committee are discussed further in [[#14.4.3|Section 14.4.3]] below. The relevant COP decision also established the Capacity-building Initiative for Transparency ( [[#UNFCCC--2016a|UNFCCC 2016a]] , para. 84), which is managed by the GEF and designed to support developing country Parties in meeting the reporting and transparency requirements under Article 13 of the Paris Agreement ( [[#Robinson--2018|Robinson 2018]] ).

Studies on past capacity-building support for climate mitigation offer some lessons for ensuring effectiveness of arrangements under the Paris Agreement. For example, [[#Umemiya--2020|Umemiya et al. (2020)]] suggest the need for a common monitoring system at the global level, and evaluation research at the project level, to achieve more effective capacity-building support. [[#Khan--2020|Khan et al. (2020)]] articulate ‘four key pillars’ of a sustainable capacity-building system for implementation of NDCs in developing countries: universities in developing countries as institutional hubs; strengthened civil society networks and partnerships; long-term programmatic finance support; and consideration of a capacity-building mechanism under the UNFCCC – paralleling the Technology Mechanism – to marshal, coordinate and monitor capacity-building activities and resources.

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<span id="implementation-and-compliance"></span>
==== 14.3.2.11 Implementation and Compliance ====

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The Paris Agreement establishes a mechanism to facilitate implementation and promote compliance under Article 15. This mechanism is to operate in a transparent, non-adversarial and non-punitive manner ( [[#Voigt--2016|Voigt 2016]] ; [[#Campbell-Duruflé--2018b|Campbell-Duruflé 2018b]] ; [[#Oberthür--2018|Oberthür and Northrop 2018]] ) that distinguishes it from the more stringent compliance procedures of the Kyoto Protocol’s Enforcement branch. The Paris Rulebook elaborated the modalities and procedures for the implementation and compliance mechanism, specifying the nature and composition of the compliance committee, the situations triggering its procedures, and the facilitative measures it can apply, which include a ‘finding of fact’ in limited situations, dialogue, assistance and recommendations ( [[#UNFCCC--2019e|UNFCCC 2019e]] ). The compliance committee is focused on ensuring compliance with a core set of binding procedural obligations ( [[#UNFCCC--2019j|UNFCCC 2019j]] , Annex, Para. 22). This compliance committee, characterised as ‘one of its kind’ and an ‘an important cornerstone’ of the Agreement’s legitimacy, effectiveness and longevity ( [[#Zihua--2019|Zihua et al. 2019]] ), is designed to facilitate compliance rather than penalise non-compliance.

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<span id="box-14.1-key-features-of-the-paris-agreement-relevant-to-mitigation"></span>
=== Box 14.1 | Key Features of the Paris Agreement Relevant to Mitigation ===

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The Paris Agreement’s overall aim is to strengthen the global response to the threat of climate change, in the context of sustainable development and efforts to eradicate poverty. This aim is explicitly linked to enhancing implementation of the UNFCCC, including its objective in Article 2 of stabilising greenhouse gas concentrations at a level that would ‘prevent dangerous anthropogenic interference with the climate system’. The Agreement sets three goals:

i. '''Temperature:''' holding the global average temperature increase 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.

ii. '''Adaptation and climate resilience:''' increasing the ability to adapt to the adverse impacts of climate change and foster climate resilience and low greenhouse gas emissions development, in a manner that does not threaten food production.

iii. '''Finance:''' making finance flows consistent with a pathway towards low greenhouse gas emissions and climate-resilient development.

In order to achieve the long-term temperature goal, Parties aim to reach global peaking of emissions as soon as possible, recognising that peaking will take longer for developing countries, and then to undertake rapid reductions in accordance with the best available science. This is designed to reach global net zero GHG emissions in the second half of the century, with the emissions reductions effort to be determined on the basis of equity and in the context of sustainable development and efforts to eradicate poverty. In addition, implementation of the Agreement as a whole is expected to reflect equity and Parties’ ‘common but differentiated responsibilities and respective capabilities’, in light of different national circumstances.

The core mitigation commitments of Parties under the Paris Agreement centre on preparing, communicating and maintaining successive ‘Nationally Determined Contributions’ (NDCs), the contents of which countries determine for themselves. All Parties must have NDCs and pursue domestic mitigation measures with the aim of achieving the objectives of their NDCs, but Parties’ NDCs are neither subject to a review of adequacy (at an individual level) nor to legally binding obligations of result. The compliance mechanism is correspondingly facilitative.

The Paris Agreement establishes a global goal on adaptation, and recognises the importance of averting, minimising and addressing loss and damage associated with the adverse effects of climate change.

The efficacy of the Paris Agreement in achieving its goals is therefore dependent upon at least three additional elements:

i. '''Ratcheting of NDCs:''' Parties must submit a new or updated NDC every five years that is in line with the Paris Agreement’s expectations of progression over time and the Party’s highest possible ambition, reflecting common but differentiated responsibilities and respecti ''v'' e capabilities in light of different national circumstances.

Box 14.1

ii. '''Enhanced transparency framework:''' Parties’ actions to implement their NDCs are subject to international transparency and review requirements, which will generate information that may also be used by domestic constituencies and peers to pressure governments to increase the ambition of their NDCs.

iii. '''Collective global stocktake:''' The global stocktake undertaken every five years, starting in 2023, will review the collective progress of countries in achieving the Paris Agreement’s goals, in light of equity and best available science. The outcome of the global stocktake informs Parties in updating and enhancing their subsequent NDCs.

These international processes establish an iterative ambition cycle for the preparation, communication, implementation and review of NDCs.

For developing countries, the Paris Agreement recognises that increasing mitigation ambition and realising long-term low-emissions development pathways can be bolstered by the provision of financial resources, capacity building, and technology development and transfer. In continuation of existing obligations under the Convention, developed countries are obliged to provide financial assistance to developing countries with respect to mitigation and adaptation. The Paris Agreement also recognises that Parties may choose to voluntarily cooperate in the implementation of their NDCs to allow for higher ambition in their mitigation and adaptation actions and to promote sustainable development and environmental integrity.

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=== 14.3.3 Effectiveness of the Kyoto Protocol and the Paris Agreement ===

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==== 14.3.3.1 Ex-post Assessment of the Kyoto Protocol’s Effects ====

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Previous assessment reports have assessed the Kyoto Protocol with respect to each of the criteria identified in this chapter. However, at the time of AR5, it was premature to assess the impact of Kyoto on emissions, as these data had not been entirely compiled yet. Since AR5, a number of studies have done so. [[IPCC:Wg3:Chapter:Chapter-2|Chapter 2]] of this report lists at least 18 countries that have sustained absolute emissions reductions for at least a decade, nearly all of which are countries that had Kyoto targets for the first commitment period. Most studies have concluded that Kyoto did cause emissions reductions. Such studies find a positive, statistically significant impact on emissions reductions in Annex I countries ( [[#Kim--2020|Kim et al. 2020]] ), Annex B countries ( [[#Grunewald--2012|Grunewald and Martínez-Zarzoso 2012]] ; Kumazawa and Callaghan 2012; [[#Grunewald--2016|Grunewald and Martínez-Zarzoso 2016]] ; [[#Maamoun--2019|Maamoun 2019]] ), or all countries respectively ( [[#Aichele--2013|Aichele and Felbermayr 2013]] ; [[#Iwata--2014|Iwata and Okada 2014]] ). Overall, countries with emissions reduction obligations emit on average less CO 2 than similar countries without emissions reduction obligations – with estimates ranging from 3–50% ( [[#Grunewald--2012|Grunewald and Martínez-Zarzoso 2012]] , 2016). [[#Maamoun--2019|Maamoun (2019)]] estimates that the Kyoto Protocol reduced GHG emissions of Annex B countries by 7% on average below a no-Kyoto scenario between 2005 and 2012. [[#Aichele--2013|Aichele and Felbermayr (2013)]] conclude that Kyoto reduced CO 2 and GHG emissions by 10% compared to the counterfactual. By contrast, [[#Almer--2017|Almer and Winkler (2017)]] find no evidence for binding emission targets under Kyoto inducing significant and lasting emissions reductions for any of the Annex B or non-Annex B countries. The authors identify both negative and positive associations between Kyoto and emissions for several countries in several years, but no coherent picture emerges. [[#Hartl--2019|Hartl (2019)]] calculates a Kyoto leakage share in global CO 2 trade of 4.3% for 2002–2009.

In terms of transformative potential, the Kyoto Protocol has been found to increase international patent applications for renewable energy technologies, especially in the case of solar energy technologies and especially in countries with more stringent emissions reduction targets, and has even led to an increase in patent applications in developing countries not obliged to reduce emissions under Kyoto ( [[#Miyamoto--2019|Miyamoto and Takeuchi 2019]] ). Kyoto also had a positive and statistically significant impact on the cost-effectiveness of renewable energy projects, as well as renewable energy capacity development, as it stimulated the introduction of domestic renewable energy policies ( [[#Liu--2019|Liu et al. 2019]] ).

The issue of institutional strength of Kyoto has been analysed by many authors, and much of this has been assessed in previous assessment reports. Since AR5, several papers question the environmental efficacy of the Kyoto Protocol based on its institutional design ( [[#Rosen--2015|Rosen 2015]] ; [[#Kuriyama--2018|Kuriyama and Abe 2018]] ). Particular attention has focused on Kyoto’s market mechanisms ( [[#Erickson--2014|Erickson et al. 2014]] ; [[#Kollmuss--2015|Kollmuss et al. 2015]] ).

As described in previous IPCC reports and above, the 1997 Kyoto Protocol included three international market-based mechanisms. These operated among Annex I Parties (i.e., International Emissions Trading and Joint Implementation) and between Annex I Parties and non-Annex I countries (i.e., the CDM) ( [[#Grubb--2014|Grubb et al. 2014]] ; [[#World%20Bank--2018|World Bank 2018]] ). Joint Implementation led to limited volumes of emissions credit transactions, mostly from economies in transition but also some Western European countries; International Emissions Trading also led only to limited transaction volumes ( [[#Shishlov--2016|Shishlov et al. 2016]] ).

Of the Kyoto Protocol’s mechanisms, the CDM market has led to a greater amount of activity, with a ‘gold rush’ period between 2005 and 2012. The main buyers of CDM credits were private companies surrendering them within the European Union (EU) Emissions Trading System (ETS). Once the EU tightened its rules and restricted the use of CDM credits in 2011, there was a sharp drop in the price of CDM credits in 2012. This price never recovered, as the demand for CDM was very weak after 2012, in part because of the difficulties encountered in securing the entry into force of the Doha Amendment ( [[#Michaelowa--2019b|Michaelowa et al. 2019b]] ).

Assessing the effectiveness of Kyoto’s market mechanisms is challenging, and the results have been mixed ( [[#Aichele--2013|Aichele and Felbermayr 2013]] ; [[#Iwata--2014|Iwata and Okada 2014]] ; [[#Kuriyama--2018|Kuriyama and Abe 2018]] ). [[#Kuriyama--2018|Kuriyama and Abe (2018)]] assessed emissions reduction quantities taking into account heightened criteria for additionality. They identified annual energy-related emissions reductions of 49 MtCO 2 -eq yr –1 flowing from the CDM, and non-energy related emissions reductions of 177 MtCO 2 -eq yr –1 . Others have pointed to issues associated with non-energy related emissions reductions that suggest the latter estimate may be of questionable reliability, while also noting that regulatory tightening led later CDM projects to perform better with respect to the additionality criterion ( [[#Michaelowa--2019b|Michaelowa et al. 2019b]] ). The CDM’s contribution to capacity building in some developing countries has been identified as possibly its most important achievement ( [[#Spalding-Fecher--2012|Spalding-Fecher et al. 2012]] ; [[#Gandenberger--2015|Gandenberger et al. 2015]] ; [[#Murata--2016|Murata et al. 2016]] ; [[#Xu--2016|Xu et al. 2016]] ; [[#Dong--2017|Dong and Holm Olsen 2017]] ; [[#Lindberg--2018|Lindberg et al. 2018]] ). There is evidence that the CDM lowered compliance costs for Annex 1 countries by at least USD3.6 billion ( [[#Spalding-Fecher--2012|Spalding-Fecher et al. 2012]] ). In host countries, the CDM led to the establishment of national approval bodies and the development of an ecosystem of consultants and auditors ( [[#Michaelowa--2019b|Michaelowa et al. 2019b]] ).

On the negative side, there are numerous findings that the CDM, especially at first, failed to lead to additional emissions cuts in host countries, meaning that the overall effect of CDM projects was to raise global emissions. [[#Cames--2016|Cames et al. (2016)]] concluded that over 70% of CDM projects led to emissions reductions that were likely less than projected, including the absence of additional reductions, while only 7% of projects led to actual additional emissions reductions that had a high likelihood of meeting or exceeding the ''ex-ante'' estimates. The primary reason the authors gave was associated with the low price for CDM credits; this meant that the contribution of the CDM to project finance was negligible, suggesting that most CDM projects would have been built anyway. A meta-analysis of ''ex-post'' studies of global carbon markets, which include the CDM, found net combined effects on emissions to be negligible ( [[#Green--2021|Green 2021]] ). Across the board, CDM projects have been criticised for lack of ‘additionality’, problems of baseline determination, uneven geographic coverage ( [[#Michaelowa--2011a|Michaelowa and Michaelowa 2011a]] ; [[#Cames--2016|Cames et al. 2016]] ; [[#Michaelowa--2019b|Michaelowa et al. 2019b]] ), as well as failing to address human rights concerns ( [[#Schade--2014|Schade and Obergassel 2014]] ).

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==== 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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=== Cross-Chapter Box 10 | Policy Attribution – Methodologies for Estimating the Macro-level Impact of Mitigation Policies on Indices of Greenhouse Gas Mitigation ===

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'''Authors:''' Mustafa Babiker (Sudan/Saudi Arabia), Paolo Bertoldi (Italy), Christopher Bataille (Canada), Felix Creutzig (Germany), Navroz K. Dubash (India), Michael Grubb (United Kingdom), Erik Haites (Canada), Ben Hinder (United Kingdom), Janna Hoppe (Switzerland), Yong-Gun Kim (Republic of Korea), Gregory F. Nemet (the United States of America/Canada), Anthony Patt (Switzerland), Yamina Saheb (France), Raphael Slade (United Kingdom)

This report notes both a growing prevalence of mitigation policies over the past quarter century (Chapter 13), and ‘signs of progress’ including various quantified indices of GHG mitigation (Table 2.4). Even though policies implemented and planned to date are clearly insufficient for meeting the Paris long-term temperature goals, a natural question is to what extent the observed macro-level changes (global, national, sectoral, technological) can be attributed to policy developments. This Assessment Report is the first to address that question. This box describes the methods for conducting such ‘attribution analysis’ as well as its key results, focusing on the extent to which polices have affected three main types of ‘outcome indices’:

'''•''' '''GHG emissions:''' emissions volumes and trends at various levels of governance including sub- and supra-national levels, and within and across sectors.

'''•''' '''Proximate emission drivers:''' trends in the factors that drive emissions, distinguished through decomposition analyses, notably: energy/GDP intensity and carbon/energy intensity (for energy-related emissions); indices of land use such as deforestation rates (for LULUCF/AFOLU); and more sector-specific component drivers such as the floor area per capita, or passenger kilometres per capita.

'''•''' '''Technologies:''' developments in key low-carbon technologies that are likely to have a strong influence on future emissions trends, notably levels of new investment and capacity expansions, as well as technology costs, with a focus on those highlighted in Figure 2.30.

''Policy attribution'' examines the extent to which emission-relevant outcomes on these indices – charted for countries, sectors and technologies, particularly in [[IPCC:Wg3:Chapter:Chapter-2|Chapter 2]] and the sectoral chapters – may be reasonably attributed to policies implemented prior to the observed changes. Such policies include regulatory instruments such as energy efficiency programmes or technical standards and codes, carbon pricing, financial support for low-carbon energy technologies and efficiency, voluntary agreements, and regulation of land-use practices. The sectoral chapters give more detail along with some accounts of policy, while trends in mitigation policy adoption are summarised in Chapter 13.

In reviewing hundreds of scientific studies cited in this report, the impacts of adopted policies on observed outcomes were assessed. The vast majority of these studies examine particular instruments in particular contexts, as covered in the sectoral chapters and Chapter 13; only a few have appraised global impacts of policies, directly or plausibly inferred (the most significant are cited in Figure 1 in this Cross-Chapter Box). Typically, studies consider ‘mitigation policies’ to be those adopted with either a primary objective of reducing GHG emissions or emissions reductions as one among multiple objectives.

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[[File:fa94f77b8fd08d8a1408bd3d8665401a IPCC_AR6_WGIII_CCBox_10_Figure_1.png]]

'''Cross-Chapter Box 10, Figure 1 | Policy impacts on key outcome indices.''' '''The figure shows the impacts of policies on three indices: proximate emission drivers, technologies and GHG emissions, including several lines of evidence on GHG abatement attributable to policies.'''

Policies differ in design, scope, and stringency, may change over time as they require amendments or new laws, and often partially overlap with other instruments. Overall, the literature indicates that policy mixes are, theoretically and empirically, more effective in reducing emissions, stimulating innovation, and inducing behavioural change than stand-alone policy instruments (Sections 5.6 and 13.7) ( [[#Rosenow--2017|Rosenow et al. 2017]] ; [[#Best--2018|Best and Burke 2018]] ; [[#Sethi--2020|Sethi et al. 2020]] ). Nevertheless, these factors complicate analysis, because they give rise to the potential for double counting emissions reductions that have been observed, and which separate studies can attribute to different policy instruments.

Efforts to attribute observed outcomes to a policy or policy mix is also greatlycomplicated by the influence of many exogenous factors, including fossil fuel prices and socio-economic conditions. Likewise, technological progress can result from both exogenous causes, such as ‘spillover’ from other sectors, and policy pressure. Further, other policies, such as fossil fuel subsidies as well as trade-related policies, can partially counteract the effect of mitigation policies by increasing the demand for energy or carbon-intensive goods and services. In some cases, policies aimed at development, energy security, or air quality have climate co-benefits, while others increase emissions.

Studies have applied a number of methods to identify the actual effects of mitigation policies in the presence of such confounding factors. These include statistical attribution methodologies, including experimental and quasi-experimental design, instrumental variable approaches, and simple correlational methods. Typically, the relevant mitigation metric is the outcome variable, while measures of policies and other factors act as explanatory variables. Other methodologies include aggregations and extrapolations

Cross-Chapter Box 10

from micro-level data evaluation, and inference from combining multiple lines of analysis, including expert opinion. Additionally, the literature contains reviews, many of them systematic in nature, that assess and aggregate multiple empirical studies.

With these considerations in mind, multiple lines of evidence, based upon the literature, support a set of high-level findings, as illustrated in Figure 1 in this Cross-Chapter Box, as follows.

'''1. GHG Emissions.''' There is robust evidence with a high level of agreement that mitigation policies have had a discernible impact on emissions. Several lines of evidence indicate that mitigation policies have led to avoided global emissions to date of several billion tonnes CO 2 -eq annually. The figure in this box shows a selection of results giving rise to this estimate.

As a starting point, one methodologically sophisticated econometric study links global mitigation policies (defined as climate laws and executive orders) to emission outcomes; it estimates emission savings of 5.9 GtCO 2 yr –1 in 2016 compared to a no-policy world ( [[#Eskander--2020|Eskander and Fankhauser 2020]] ) ( [[IPCC:Wg3:Chapter:Chapter-13#13.6.2|Section 13.6.2]] ).

A second line of evidence derives from analyses of the Kyoto Protocol. Countries which took on Kyoto Protocol targets accounted for about 24% of global emissions during the first commitment period (2008–12). The most recent robust econometric assessment ( [[#Maamoun--2019|Maamoun 2019]] ) estimates that these countries cut GHG emissions by about 7% on average over 2005–2012, rising over the period to around 12% (1.3 GtCO 2 -eq yr –1 ) ''relative to a no-Kyoto scenario.'' This is consistent with estimates of Grunewald and Martinez (2016) of about 800 MtCO 2 -eq yr –1 averaged to 2009. Developing countries’ emissions reduction projects through the CDM (defined in Article 12 of the Kyoto Protocol) were certified as growing to over 240 MtCO 2 -eq yr –1 by 2012 (UNFCC 2021c). With debates about the full

Cross-Chapter Box 10

extent of ‘additionality’, academic assessments of savings from the CDM have been slightly lower, with particular concerns around some non-energy projects ( [[#14.3.3.1|Section 14.3.3.1]] ).

A third line of evidence derives from studies that identify policy-related, absolute reductions from historical levels in particular countries and sectors through decomposition analyses (Le Quéré et al. 2019; [[#Lamb--2021|Lamb et al. 2021]] ), or evaluate the impact of particular policies, such as carbon pricing systems. From a wide range of estimates in the literature (Sections 2.8.2.2 and 13.6), many evaluations of the EU ETS suggest that it has reduced emissions by around 3% to 9% relative to unregulated firms and/or sectors ( [[#Schäfer--2019|Schäfer 2019]] ; Colmer et al. 2020), while other factors, both policy (energy efficiency and renewable support) and exogenous trends, played a larger role in the overall reductions seen ( [[#Haites--2018|Haites 2018]] ).

These findings derived from the peer-reviewed literature are also consistent with two additional sets of analysis. The first set concerns trends in emissions, drawing directly from Chapters 2, 6 and 11, showing that global annual emission growth has slowed, as evidenced by annual emission increments of 0.55 GtCO 2 -eq yr –1 between 2011 and 2019 compared to 1.014 GtCO 2 -eq yr –1 in 2000 and 2008. This suggests avoided emissions of 4–5 GtCO 2 -eq yr –1 (see also Figure 1.1d). The second set concerns emissions reductions projected by Annex I governments for 2020 in their fourth biennial reports to the UNFCCC. It is important to note that these are mostly projected annual savings from implemented policies (not ''ex-post'' evaluations), and there are considerable differences in countries’ estimation methodologies. Nevertheless, combining estimates from 38% of the total of 2,811 reported policies and measures yields an overall estimate of 3.81 GtCO 2 -eq yr –1 emission savings ( [[#UNFCCC--2020d|UNFCCC 2020d]] ).

'''2. Proximate''' '''emission drivers.''' With less overt focus on emissions, studies of trends in energy efficiency, carbon intensity, or deforestation often point to associated policies. The literature includes an increasing number of studies on demonstrable progress in developing countries. For example, South and South-East Asia have seen energy intensity in buildings improving at about 5–6% yr –1 since 2010 (Figure 2.22). In India alone, innovative programmes in efficient air conditioning, LED lighting, and industrial efficiency are reported as saving around 25 Mtoe in 2019–2020, thus leading to avoided emissions of over 150 MtCO 2 yr –1 ( [[#Malhotra--2021|Malhotra et al. 2021]] ) (Box 16.3). Likewise, reductions in deforestation rates in several South and Central American and Asian countries are at least partly attributable to ecosystem payments, land-use regulation, and internal efforts ( [[IPCC:Wg3:Chapter:Chapter-7#7.6.2|Section 7.6.2]] ). Finally, the policy-driven displacement of fossil fuel combustion by renewables in energy has led to reductions in carbon intensity in several world regions (Chapters 2 and 6).

'''3. Technologies.''' The literature indicates unambiguously that the rapid expansion of low-carbon energy technologies is substantially attributable to policy (Sections 6.7.5 and 16.5). Technology-specific adoption incentives have led to a greater use of less carbon-intensive (e.g., renewable electricity) and less energy-intensive (especially in transport and buildings) technologies. As Chapters 2 and 6 of this report note that modern renewable energy sources currently satisfy over 9% of global electricity demand, and this is largely attributable to policy. There are no global-level studies estimating the avoided emissions due to renewable energy support policies, but there are methods that have been developed to link renewable energy penetration to avoided emissions, such as that of [[#IRENA--2021|IRENA (2021)]] . Using that method, and assuming that 70% of modern renewable energy expansion has been policy induced, yields an estimate of avoided emissions of 1.3 GtCO 2 -eq yr –1 in 2019. Furthermore, observed cost reductions are the result of policy-driven capacity expansion as well as publicly funded resarch and development, in individual countries and globally. These correspond with induced effects on number of patents, ‘learning curve’ correlations with deployed capacity, and cost component and related case study analyses ( [[#Kavlak--2018|Kavlak et al. 2018]] ; [[#Nemet--2019|Nemet 2019]] ; [[#Popp--2019|Popp 2019]] ; [[#Grubb--2021|Grubb et al. 2021]] ).

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