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

==== 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]] ).

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