Editing IPCC:AR6/WGIII/Chapter-12 (section)

== Executive Summary ==

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'''The total emission mitigation potential achievable by the year 2030, calculated based on sectoral assessments, is sufficient to reduce global greenhouse gas emissions to half of the current (2019) level or less (''' '''''robust evidence''''' ''',''' '''''high agreement''''' ''').''' This potential (32–44 GtCO 2 -eq) requires implementation of a wide range of mitigation options. Options with mitigation costs lower than USD20 tCO 2 –1 make up more than half of this potential and are available for all sectors. {12.2, Table 12.3}

'''Carbon dioxide removal (CDR) is a necessary element to achieve net zero CO''' 2 '''and greenhouse gas (GHG) emissions both globally and nationally, counterbalancing residual emissions from hard-to-transition sectors. It is a key element in scenarios that limit warming to 2°C (&gt;67%) or lower by 2100 (''' '''''robust evidence''''' ''',''' '''''high agreement''''' ''').''' Implementation strategies need to reflect that CDR methods differ in terms of removal process, timescale of carbon storage, technological maturity, mitigation potential, cost, co-benefits, adverse side effects, and governance requirements. All Illustrative Mitigation Pathways (IMPs) use land-based biological CDR (primarily afforestation/reforestation (A/R)) and/or bioenergy with carbon capture and storage (BECCS) and some include direct air carbon capture and storage (DACCS). As a median value (5–95% range) across the scenarios that limit warming to 2°C (&gt;67%) or lower, cumulative volumes of BECCS, CO 2 removal from AFOLU (mainly A/R), and DACCS reach 328 (168–763) gigatonnes of CO 2 equivalent (GtCO 2 ), 252 (20–418) GtCO 2 , and 29 (0–339) GtCO 2 for the 2020–2100 period, with annual volumes at 2.75 (0.52–9.45) GtCO 2 yr –1 for BECCS, 2.98 (0.23–6.38) GtCO 2 yr –1 for the CO 2 removal from AFOLU (mainly A/R), and 0.02 (0–1.74) GtCO 2 yr –1 for DACCS, in 2050. {12.3, Cross-Chapter Box 8 in this chapter}

'''Despite limitedcurrent deployment, moderate to large future mitigation potentials are estimated for direct air carbon capture and sequestration (DACCS), enhanced weathering (EW) and ocean-based CDR methods (including ocean alkalinity enhancement and ocean fertilisation) (''' '''''medium evidence''''' ''',''' '''''medium agreement''''' ''').''' The potential for DACCS (5–40 GtCO 2 yr –1 ) is limited mainly by requirements for low-carbon energy and by cost (USD100–300 (full range: USD84–386) tCO 2 –1 ). DACCS is currently at a medium technology readiness level. EW has the potential to remove 2–4 (full range: &lt;1 to about 100) GtCO 2 yr –1 , at costs ranging from USD50 to 200 (full range: USD24–578) tCO 2 –1 . Ocean-based methods have a combined potential to remove 1–100 GtCO 2 yr –1 at costs of USD40–500 tCO 2 –1 , but their feasibility is uncertain due to possible side effects on the marine environment. EW and ocean-based methods are currently at a low technology readiness level. {12.3}

'''Realising the full mitigation potential from the food system requires change at all stages from producer to consumer and waste management, which can be facilitated through integrated policy packages''' '''(''' '''''robust evidence''''' ''',''' '''''high agreement''''' ''').''' Some 23–42% of global GHG emissions are associated with food systems, while there is still widespread food insecurity and malnutrition. Absolute GHG emissions from food systems increased from 14 to 17 GtCO 2 -eq yr –1 in the period 1990–2018. Both supply and demand-side measures are important to reduce the GHG intensity of food systems. Integrated food policy packages based on a combination of market-based, administrative, informative, and behavioural policies can reduce cost compared to uncoordinated interventions, address multiple sustainability goals, and increase acceptance across stakeholders and civil society ( ''limited evidence'' , ''medium agreement'' ) ''.'' {7.2, 7.4, 12.4}

'''Diets high in plant protein and low in meat and dairy are associated with lower GHG emissions (''' '''''robust evidence''''' ''',''' '''''high agreement''''' ''').''' Ruminant meat shows the highest GHG intensity. Beef from dairy systems has lower emissions intensity than beef from beef herds (8–23 and 17–94 kgCO 2 -eq per 100 g protein, respectively) when a share of emissions is allocated to dairy products. The wide variation in emissions reflects differences in production systems, which range from intensive feedlots with stock raised largely on grains through to rangeland and transhumance production systems. Where appropriate, a shift to diets with a higher share of plant protein, moderate intake of animal-source foods and reduced intake of added sugars, salt and saturated fats could lead to substantial decreases in GHG emissions. Benefits would also include reduced land occupation and nutrient losses to the surrounding environment, while at the same time providing health benefits and reducing mortality from diet-related non-communicable diseases. {7.4.5, 12.4}

'''Emerging food technologies such as cellular fermentation, cultured meat, plant-based alternatives to animal-based food products, and controlled-environment agriculture, can bring substantial reductions in direct GHG emissions from food production (''' '''''limited evidence''''' ''',''' '''''high agreement''''' ''').''' These technologies have lower land, water, and nutrient footprints, and address concerns over animal welfare. Access to low-carbon energy is needed to realise the full mitigation potential, as some emerging technologies are relatively more energy intensive. This also holds for deployment of cold chain and packaging technologies, which can help reduce food loss and waste, but increase energy and materials use in the food system. ( ''limited evidence'' , ''high agreement'' ). {11.4.1.3, 12.4}

'''Scenarios that limit warming to 2°C (&gt;67%) or lower by 2100 commonly involve extensive mitigation in the agriculture, forestry and other land use (AFOLU) sector that at the same time provides biomass for mitigation in other sectors. Bioenergy is the most land intensive renewable energy option, but the total land occupation of other renewable energy options can become significant in high deployment scenarios (''' '''''robust evidence''''' ''',''' '''''high agreement''''' ''').''' Growing demands for food, feed, biomaterials, and non-fossil fuels increase the competition for land and biomass while climate change creates additional stresses on land, exacerbating existing risks to livelihoods, biodiversity, human and ecosystem health, infrastructure, and food systems. Appropriate integration of bioenergy and other bio-based systems, and of other mitigation options, with existing land and biomass uses can improve resource use efficiency, mitigate pressures on natural ecosystems and support adaptation through measures to combat land degradation, enhance food security, and improve resilience through maintenance of the productivity of the land resource base ( ''medium evidence'' , ''high agreement'' ). {3.2.5, 3.4.6, 12.5}

'''Bio-based products as part of a circular bioeconomy have potential to support adaptation and mitigation. Key to maximising benefits and managing trade-offs are sectoral integration, transparent governance, and stakeholder involvement (''' '''''high confidence''''' ''')''' '''''.''''' A sustainable bioeconomy relying on biomass resources will need to be supported by technology innovation and international cooperation and governance of global trade to disincentivise environmental and social externalities ( ''medium confidence'' ). {12.5, Cross-Working Group Box 3 in this chapter}

'''Coordinated, cross-sectoral approaches to climate change mitigation should be adopted to target synergies and minimise trade-offs between sectors and with respect to sustainable development (''' '''''robust evidence''''' ''',''' '''''high agreement''''' ''').''' This requires integrated planning using multiple-objective-multiple-impact policy frameworks. Strong interdependencies and cross-sectoral linkages create both opportunities for synergies and the need to address trade-offs related to mitigation options and technologies. This can only be done if coordinated sectoral approaches to climate change mitigation policies that mainstream these interactions are adopted ''.'' Integrated planning and cross-sectoral alignment of climate change policies are particularly evident in developing countries’ Nationally Determined Contributions (NDCs) pledged under the Paris Agreement, where key priority sectors such as agriculture and energy are closely aligned between the proposed mitigation and adaptation actions in the context of sustainable development and the Sustainable Development Goals (SDGs) ''.'' {12.6.2}

'''Carbon leakage is a critical cross-sectoral and cross-country consequence of differentiated climate policy''' '''(''' '''''robust evidence''''' ''',''' '''''medium agreement''''' ''').''' Carbon leakage occurs when mitigation measures implemented in one country/sector lead to increased emissions in other countries/sectors. Global commodity value chains and associated international transport are important mechanisms of carbon leakage. Reducing emissions from the value chain and transportation can offer opportunities to mitigate three elements of cross-sectoral spillovers and related leakage: (i) domestic cross-sectoral spillovers within the same country; (ii) international spillovers within a single sector resulting from substitution of domestic production of carbon-intensive goods with their imports from abroad; and (iii) international cross-sectoral spillovers among sectors in different countries ''.'' {12.6.3}

'''Cross-sectoral considerations in mitigation finance are critical for the effectiveness of mitigation action as well as for balancing the often conflicting social, developmental, and environmental policy goals at the sectoral level (''' '''''medium evidence''''' ''',''' '''''medium agreement''''' ''').''' True resource mobilisation plans that properly address mitigation costs and benefits at sectoral level cannot be developed in isolation from their cross-sectoral implications. There is an urgent need for multilateral financing institutions to align their frameworks and delivery mechanisms including the use of blended financing to facilitate cross-sectoral solutions as opposed to causing competition for resources among sectors ''.'' {12.6.4}

'''Understanding the co-benefits and trade-offs associated with mitigation is key to supporting societies to prioritise among the various sectoral policy options (''' '''''medium evidence''''' ''',''' '''''medium agreement''''' ''').''' For example, CDR options can have positive impacts on ecosystem services and the SDGs, but also potential adverse side effects; transforming food systems has potential co-benefits for several SDGs, but also trade-offs; and land-based mitigation measures may have multiple co-benefits but may also be associated with trade-offs among environmental, social, and economic objectives. Therefore, the possible implementation of the different sectoral mitigation options would depend on how societies prioritise mitigation versus other products and services, including food, material well-being, nature conservation and biodiversity protection, as well as on other considerations such as society’s future dependence on CDR and on carbon-based energy and materials. {12.3, 12.4, 12.5, 12.6.1}

'''Governance of CDR, food systems and land-based mitigation can support effective and equitable policy implementation (''' '''''medium evidence''''' ''',''' '''''high agreement''''' ''').''' Effectively responding to climate change while advancing sustainable development will require coordinated efforts among a diverse set of state- and non-state-actors on global, multinational, national, and sub-national levels. Governance arrangements in public policy domains that cut through traditional sectors are confronted with specific challenges, such as establishing reliable systems for monitoring, reporting and verification (MRV) that allow evaluation of mitigation outcomes and co-benefits. Effectively integrating CDR into mitigation portfolios can build on already existing rules, procedures and instruments for emissions abatement. Additionally, to accelerate research, development, and demonstration, and to incentivise CDR deployment, a political commitment to formal integration into existing climate policy frameworks is required, including reliable MRV of carbon flows. Food systems governance may be pioneered through local food policy initiatives complemented by national and international initiatives, but governance on the national level tends to be fragmented, and thus have limited capacity to address structural issues like inequities in access. The governance of land-based mitigation, including land-based CDR, can draw on lessons from previous experience with regulating biofuels and forest carbon; however, integrating these insights requires governance that goes beyond project-level approaches and emphasises integrated land use-planning and management within the frame of the SDGs. {7.4, Box 7.2, 7.6, 12.3.3, 12.4, 12.5}

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