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

== Executive Summary ==

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This chapter focuses on accelerating mitigation and on shifting development pathways to increased sustainability, based on literature particularly at national scale. While previous WGIII assessments have discussed mitigation pathways, focus on development pathways is more recent. The timeframe is the near term (now up to 2030) to mid-term (2030 to 2050), complementing [[IPCC:Wg3:Chapter:Chapter-3|Chapter 3]] on the long term (from 2050 onward).

'''An emissions gap persists, exacerbated by an implementation gap, despite mitigation efforts including those in near-universal nationally determined contributions (NDCs).''' The ‘emissions gap’ is understood as the difference between the emissions with NDCs in 2030, and mitigation pathways consistent with the temperature goals. In general, the term ‘implementation gap’ refers to the difference between goals on paper and how they are achieved in practice. In this report, the term refers to the gap between mitigation pledges contained in national determined contributions, and the expected outcome of existing policies. There is considerable literature on country-level mitigation pathways, including but not limited to NDCs. Country distribution of this literature is very unequal ( ''robust evidence'' , ''high agreement'' ). Current policies lead to median global greenhouse gas (GHG) emissions of 57 GtCO 2 -eq with a full range of 52–60 by 2030. NDCs with unconditional and conditional elements [[#footnote-005|1]] lead to 53 (50–57) and 50 (47–55) GtCO 2 -eq, respectively ( ''medium evidence'' , ''medium agreement'' ) (Table 4.3). This leaves estimated emissions gaps in 2030 between projected outcomes of unconditional elements of NDCs and emissions in scenarios that limit warming to 1.5°C (&gt;50%) with no or limited overshoot of 19–26 GtCO 2 -eq, and 10–16 GtCO 2 -eq for scenarios that limit warming to 2°C (&gt;67%) with immediate action. When conditional elements of NDCs are included, these gaps narrow to 16–23 GtCO 2 -eq and 6–14 GtCO 2 -eq, respectively. {Cross-Chapter Box 4, Figure 1}

'''Studies evaluating up to 105 updated NDCs submitted by October 2021 indicate that emissions in conditional NDCs have been reduced by 4.5 (2.7–6.3)''' '''GtCO''' 2 '''-eq''' ''', but only closes the emission gaps by about one-third to 2°C and about 20% to 1.5°C compared to the original NDCs submitted in 2015/16 (''' '''''medium evidence''''' ''',''' '''''medium agreement''''' ''').''' The magnitude of these emission gaps calls into question whether current development pathways and efforts to accelerate mitigation are adequate to achieve the Paris mitigation objectives. In addition, an implementation gap exists between the projected emissions of ‘current policies’ and the projected emissions resulting from the implementation of the unconditional and conditional elements of NDCs, and is estimated to be around and 7 GtCO 2 -eq in 2030, respectively ( ''medium evidence'' , ''medium agreement'' ), with many countries requiring additional policies and associated climate action to meet their autonomously determined mitigation targets as specified under the first NDCs ( ''limited evidence'' ). There is, furthermore, a potential difference between mitigation targets set in NDCs ''ex ante'' and what is achieved ''ex post'' . A limited number of studies assess the implementation gaps of conditional NDCs in terms of finance, technology and capacity building support. The disruptionstriggered by the COVID-19 epidemic increase uncertainty over range of projections relative to pre-COVID-19 literature. As indicated by a growing number of studies at the national and global level, how large near- to mid-term emissions implications of the COVID-19 pandemic are, to a large degree depends on how stimulus or recovery packages are designed. {4.2, 4.2.2.5, Cross-Chapter Box 4}

'''Given the gaps, there is a need to explore accelerated mitigation (relative to NDCs and current policies).''' There is increasing understanding of the technical content of accelerated mitigation pathways, differentiated by national circumstances, with considerable though uneven literature at country-level ( ''medium evidence'' , ''high agreement'' ). Transformative technological and institutional changes for the near term include demand reductions through efficiency and reduced activity, rapid decarbonisation of the electricity sector and low-carbon electrification of buildings, industry and transport ( ''robust evidence'' , ''medium agreement'' ). A focus on energy use and supply is essential, but not sufficient on its own – the land sector and food systems deserve attention. The literature does not adequately include demand-side options and systems analysis, and captures the impact from non-CO 2 GHGs with medium confidence. Countries and regions will have different starting points for transition pathways. Some factors include climate conditions resulting in different heating and cooling needs, endowments with different energy resources, patterns of spatial development, and political and economic conditions. {4.2.5}

'''Accelerated mitigation alone may run into obstacles.''' If such obstacles are rooted in underlying structural features of society, then transforming such structures helps remove obstacles, which amounts to shifting development pathways. Various actors have developed an increasing number of mitigation strategies up to 2050 (mid-term). A growing number of such strategies aim at net zero GHG or CO 2 emissions, but it is not yet possible to draw global implications due to the limited size of sample ( ''medium evidence'' , ''low agreement'' ). Non-state actors are also engaging in a wide range of mitigation initiatives. When adding up emission reduction potentials, sub-national and non-state international cooperative initiatives could reduce up to about 20 GtCO 2 -eq in 2030 ( ''limited evidence'' , ''medium agreement'' ). Yet perceived or real conflicts between mitigation and other Sustainable Development Goals (SDGs) can impede such action. If undertaken without precaution, accelerated mitigation is found to have significant implications for development objectives and macroeconomic costs at country level. For example, most country-level mitigation modelling studies in which GDP is an endogenous variable report negative impacts of mitigation on GDP in 2030 and 2050, relative to the reference. In all reviewed studies, however, GDP continues to grow even with mitigation( ''robust evidence'' , ''high agreement'' ). The literature finds that employment effect of mitigation policies tends to be limited on aggregate, but can be significant at sectoral level ( ''limited evidence'' , ''medium agreement'' ). Detailed design of mitigation policies is critical for distributional impacts and avoiding lock-in ( ''robust evidence'' , ''high agreement'' ), though further research is needed in that direction. {4.2.3, 4.2.4, 4.2.6}

'''Shifting development pathways towards sustainability offers ways to (i) broaden the range of levers and enablers that a society can use to provide enabling conditions and accelerate mitigation; and (ii) increase the chances of advancing at the same time towards mitigation and towards other development goals.''' The way countriesdevelop determines their capacity to accelerate mitigation and achieve other sustainable development objectives simultaneously ( ''medium-robust evidence'' , ''medium agreement'' ). Yet meeting ambitious mitigation and development goals cannot be achieved through incremental change, hence the focus on shifting development pathways ( ''robust evidence'' , ''medium agreement'' ). Though development pathways result from the actions of a wide range of actors, it is possible to shift development pathways through policies and enhancing enabling conditions ( ''limited evidence'' , ''medium agreement'' ). For example, policies such as those listed in Table 4.12 are typically associated with broader objectives than greenhouse gas mitigation. They are generally conceived and implemented in the pursuit of overall societal development objectives, such as job creation, macroeconomic stability, economic growth, and public health and welfare. In some countries, such policies are framed as part of a just transition. However, they can have major influence on mitigative capacity, and hence can be seen as tools to broaden mitigation options, as illustrated by the Illustrative Mitigation Pathway ‘Shifting Pathways’ ( ''medium evidence'' , ''medium agreement'' ). There are practical options to shift development pathways in ways that advance mitigation and other sustainable development objectives, supporting political feasibility, increase resources to meet multiple goals, and reduce emissions ( ''limited evidence'' , ''high agreement'' ). Concrete examples assessed in this chapter include high employment and low emissions structural change, fiscal reforms for mitigation and social contract, combining housing policies to deliver both housing and transport mitigation, and change economic, social and spatial patterns of development of the agriculture sector provide the basis for sustained reductions in emissions from deforestation. These examples differ by context. Examples in other chapters include transformations in energy, urban, building, industrial, transport, and land-based systems, changes in behaviour and social practices, as well as transformational changes across whole economies and societies. Coordinated policy mixes would need to coordinate multiple actors – individuals, groups and collectives, corporate actors, institutions and infrastructure actors – to deepen decarbonisation and shift pathways towards sustainability. Shifts in one country may spill over to other countries. Shifting development pathways can jointly support mitigation and adaptation. Some studies explore the risks of high complexity and potential delay attached to shifting development pathways. {4.3, 4.3.1, 4.3.2, 4.4.2, 4.4.3, 4.4.1.7–4.4.1.10, Figure 4.7, Cross-Chapter Box 5, 5.8, Box 6.2, 8.2, 8.3.1, 8.4, 9.8.1, 9.8.2, 10.4.1, Cross-Chapter Box 5, Cross-Chapter Box 7, Cross-Chapter Box 12}

'''The literature identifies a broad set of enabling conditions that can both foster shifting development pathways and accelerated mitigation, along five categories''' '''(''' '''''medium evidence''''' ''', '''''high agreement''''' ).''' Policy integration is a necessary component of shifting development pathways, addressing multiple objectives. To this aim, mobilising a range of policies is preferable to single policy instruments ( ''robust evidence'' , ''high agreement'' ). Governance for climate mitigation and shifting development pathways is enhanced when tailored to national and local contexts. Improved institutions and governance enable ambitious climate action and help bridge implementation gaps ( ''medium evidence'' , ''high agreement'' ). Given that strengthening institutions may be a long term endeavour, it needs attention in the near ter m. Accelerated mitigation and shifting development pathways necessitates both redirecting existing financial flows from high- to low-emissions technologies and systems and to provide additional resources to overcome current financial barriers ( ''robust evidence'' , ''high agreement'' ). Opportunities exist in the near term to close the finance gap. At the national level, public finance for actions promoting the SDG agenda helps broaden the scope of mitigation ( ''medium evidence'' , ''medium agreement'' ). Changes in behaviour and lifestyles are important to move beyond mitigation as incremental change, and when supporting shifts to more sustainable development pathways will broadening the scope of mitigation ( ''medium evidence'' , ''medium agreement'' ). The direction of innovation matters ( ''robust evidence'' , ''high agreement'' ). The necessary transformational changes are likely to be more acceptable if rooted in the development aspirations of the economy and society within which they take place. {4.4.1, 4.4.1.2, 4.4.1.3, 4.4.1.4, 4.4.1.5, 4.4.1.6, Figure 4.8, 15.2.2}

'''Equity can be an important enabler of deeper ambition for accelerated mitigation,''' dealing with the distribution of costs and benefits and how these are shared as per social contracts, national policy and international agreements. Transition pathways have distributional consequences such as large changes in employment and economic structure ( ''robust evidence'' , ''high agreement'' ). In that regard, the just transition concept has become an international focal point tying together social movements, trade unions, and other key stakeholders to ensure equity is better accounted for in low-carbon transitions. Effectiveness of cooperative action and the perception of fairness of such arrangements are closely related, in that pathways that prioritise equity and allow broad stakeholders participation can enable broader consensus for the transformational change implied by deeper mitigation efforts ( ''robust evidence'' , ''medium agreement'' ). Hence, equity is a concept that is instrumentally important. {4.5, Figure 4.9}

'''In sum, this chapter suggests that the immediate tasks are to broaden and deepen mitigation''' in the near term if the global community is to deliver emission reductions at the scale required to keep temperature well below 2°C and pursue efforts at 1.5°C. Deepening mitigation means more rapid decarbonisation. Shifting development pathways to increased sustainability (SDPS) broadens the scope of mitigation. Putting the enabling conditions above in place supports both. Depending on context, some enabling conditions such as shifting behaviour may take time to establish, underscoring the importance of early action. Other enabling conditions, such as improved access to financing, can be put in place in a relatively short time frame, and can yield results rapidly.

'''Accelerating mitigation:''' The literature points to well-understood policy measures and technologies for accelerating mitigation, though the balance depends on country specificities: (i) decarbonising electricity supply to produce net zero CO 2 , including renewable energy, (ii) radically more efficient use of energy than today; (iii) electrification of end-uses including transport; (iv) dramatically lower use of fossil fuels than today; (v) converting other uses to low- or zero-carbon fuels (e.g., hydrogen, bioenergy, ammonia) in hard-to-decarbonise sectors; (vi) promote bioenergy, demand reduction, dietary changes, and policies, incentives, and rules for mitigation in the land sector; and (vii) setting and meeting ambitious targets to reduce methane and other short-lived climate forcers. Charting just transitions to net zero may provide a vision, which policy measures can help achieve. Though there is increasing experience with pricing carbon directly or indirectly, decision-makers might consider a broader toolbox of enablers and levers that is available in domains that have not traditionally been considered climate policy. {4.5, Annex II.IV.11}

'''Broadening opportunities''' by focusing on development pathways and considering how to shift them: Some of the policy measures may yield rapid results, whereas other, larger transformations may take longer. If we are to overcome obstacles, a near-term priority is to put in place the enabling conditions to shifting development pathways to increased sustainability. Learning from the examples above, focusing on SDPS also provides a broader set of tools to accelerating mitigation and achieve other sustainable development goals. Consider climate whenever you make choices about development, and vice versa. {4.4.1}

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