Editing IPCC:AR6/WGIII/Chapter-13 (section)

== 13.5 Sub-national Actors, Networks, and Partnerships ==

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In many countries, sub-national actors and networks are a crucial component of climate mitigation as they have remit over land-use planning, waste management, infrastructure, housing and community development, and their jurisdictions are often where the impacts of climate change are felt ( ''robust evidence'' , ''high agreement'' ). Depending on the legal framework and other institutional constraints, sub-national actors play crucial roles in developing, delivering and contesting decarbonisation visions and pathways ( [[#Schroeder--2013|Schroeder et al. 2013]] ; [[#Ryan--2015|Ryan 2015]] ; [[#Abbott--2016|Abbott et al. 2016]] ; [[#Bäckstrand--2017|Bäckstrand et al. 2017]] ; [[#Amundsen--2018|Amundsen et al. 2018]] ; [[#Fuhr--2018|Fuhr et al. 2018]] ) ( [[#13.3.3|Section 13.3.3]] ).

Sub-national actors include organisations, jurisdictions, and networks (e.g., a coalition of cities or state authorities). These are either formal or informal, profit or non-profit and public or private ( [[#Avelino--2016|Avelino and Wittmayer 2016]] ). For example, corporations are formal, private, and for-profit, the state and labour organisations are formal, public, and non-profit, and communities are private, informal, and non-profit. An intermediary sector, crossing the boundaries between private and public, for profit and non-profit, includes energy cooperatives, not-for-profit energy enterprises, and the scientific community ( [[#Avelino--2016|Avelino and Wittmayer 2016]] ).

To address the challenge of climate mitigation, a range of actors across sectors and jurisdictions have created coalitions for climate governance, operating as actor-networks. For example, mitigation policies are particularly effective when they are integrated with co-benefits such as health, biodiversity, and poverty reduction ( [[#Romero-Lankao--2018a|Romero-Lankao et al. 2018a]] ). Transnational business and public-private partnerships and initiatives, as well as international cooperation at the sub-national and city levels are discussed in Chapter 14.

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=== 13.5.1 Actor-networks and Policies ===

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The decision adopting the Paris Agreement welcomed contributions of sub-national actors to mobilising and scaling up ambitious climate action (see also Chapter 14). They engage in climate relevant mechanisms, such as the Sustainable Development Goals and the New Urban Agenda. Sub-national actors fill a gap in national policies, participate in transnational and sub-national climate governance networks and facilitate learning and exchange among governmental, community, and private organisations at multiple levels, gathering knowledge and best practices such as emission inventories and risk management tools that can be applied in multiple contexts ( [[#Kona--2016|Kona et al. 2016]] ; [[#Sharifi--2016|Sharifi and Yamagata 2016]] ; [[#Michaelowa--2017|Michaelowa and Michaelowa 2017]] ; [[#Warbroek--2017|Warbroek and Hoppe 2017]] ; [[#Bai--2018|Bai et al. 2018]] ; [[#Busch--2018|Busch et al. 2018]] ; [[#Hsu--2018|Hsu et al. 2018]] ; [[#Lee--2018|Lee and Jung 2018]] ; [[#Marvin--2018|Marvin et al. 2018]] ; [[#Romero-Lankao--2018b|Romero-Lankao et al. 2018b]] ; [[#Ürge-Vorsatz--2018|Ürge-Vorsatz and Seto 2018]] ; [[#Amundsen--2018|Amundsen et al. 2018]] ; [[#Heikkinen--2019|Heikkinen et al. 2019]] ; [[#Hultman--2020|Hultman et al. 2020]] ).

Sub-national climate change policies exist in more than 142 countries and exemplify the increasing significance of mitigation policy at the sub-national level ( [[#Hsu--2018|Hsu et al. 2018]] ). However, estimations of the number of sub-national actors pledging voluntary climate action are challenging and underreporting is a concern ( [[#Hsu--2018|Hsu et al. 2018]] ; [[#Chan--2019|Chan and Morrow 2019]] ). As can be seen in more than 10,500 cities and nearly 250 regions representing more than 2 billion people, factoring for overlaps in population between these jurisdictions, have pledged climate action as of December 2020 ( [[#Hsu--2020a|Hsu et al. 2020a]] ). More jurisdictions in Europe and North America have pledged action, but in terms of population almost all regions are substantially engaged in sub-national action.

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[[File:9534673216e4e93297acceeaff22302b IPCC_AR6_WGIII_Figure_13_3.png]]

'''Figure 13.3 | Sub-national GHG mitigation commitments: Total population by IPCC region.''' Population of sub-national actors (cities and regions) recording climate action commitments as captured in the ClimActor dataset. Population calculation considers overlap between City and Regions by only accounting for population once for Cities and Regions that are nested jurisdictions. Source: adapted with permission from [[#Hsu--2020a|Hsu et al. (2020a)]] to reflect IPCC AR6 aggregation. Compiled in 2020 from multiple sources based on most recent year of data available.

Many of these efforts are organised around transnational or regional networks. For example, a coalition of 130 sub-national (in other words, state, and regional) governments, representing 21% of the global economy and 672 million people, has pledged about 9% emissions reduction compared to a base year (CDP 2020). More than 10,000 cities, representing more than 10% of the global population, participate in the Global Covenant of Mayors, C40 Cities ( [[#Global%20Covenant%20of%20Mayors%20for%20Climate%20and%20Energy--2018|Global Covenant of Mayors for Climate and Energy 2018]] ), and ICLEI’s – Local Governments for Sustainability carbon registry ( [[#Hsu--2018|Hsu et al. 2018]] ). In Europe alone, more than 6000 cities have adopted their own climate action plans ( [[#Palermo--2020a|Palermo et al. 2020a]] ) and nearly 300 US sub-national actors – cities and states – were committed to maintaining momentum for climate action as part of the ‘We Are Still In’ coalition ( [[#We%20Are%20Still%20In%20coalition--2020|We Are Still In coalition 2020]] ) in the absence of national US climate legislation. Further, as of October 2020, more than 826 cities and 103 regional governments had made specific pledges to decarbonise, whether in a specific sector (e.g., buildings, electricity, or transport) or through their entire economies, pledging to reduce their overall emissions by at least 80% (NewClimate Institute and Data Driven EnviroLab 2020). Cities such as Barcelona, Spain and Seattle, Washington have adopted net zero goals for 2050 in policy legislation, while many more cities throughout the world, including the Global South such as Addis Ababa in Ethiopia, have net zero targets under consideration ( [[#ECIU--2019|ECIU 2019]] , 2021).

Sub-national mitigation policies are highlighted below, based on the taxonomy of policies in [[#13.6.1|Section 13.6.1]] :

a) Economic instruments: as of 2020, there were carbon pricing initiatives (ETS, carbon tax or both) in 24 sub-national jurisdictions ( [[#World%20Bank--2021a|World Bank 2021a]] ). Examples include emission trading systems within North America, such as the Regional Greenhouse Gas Initiative (RGGI) and Western Climate Initiative (which also includes two Canadian provinces); tax rebates for the purchase of EVs; a carbon tax in British Columbia;and a cap-and-trade scheme in Metropolitan Tokyo ( [[#Houle--2015|Houle et al. 2015]] ; [[#Murray--2015|Murray and Rivers 2015]] ; [[#Hibbard--2018|Hibbard et al. 2018]] ; [[#Bernard--2019|Bernard and Kichian 2019]] ; [[#Raymond--2019|Raymond 2019]] ; [[#Xiang--2019|Xiang and Lawley 2019]] ; [[#Chan--2019|Chan and Morrow 2019]] ).

b) Regulatory instruments: policies such as land use and transportation planning, performance standards for buildings, utilities, transport electrification, and energy use by public utilities, buildings and fleets are widely prevalent ( [[#Bulkeley--2013|Bulkeley 2013]] ; [[#Jones--2013|Jones 2013]] ; [[#C40%20and%20ARUP--2015|C40 and ARUP 2015]] ; [[#Martinez--2015|Martinez et al. 2015]] ; [[#Hewitt--2019|Hewitt and Coakley 2019]] ; [[#Palermo--2020b|Palermo et al. 2020b]] ). Policies such as regulatory restrictions, low emission zones, parking controls, delivery planning and freight routes, focus on traffic management and reduction of local air pollution but also have a mitigation impact ( [[#Slovic--2016|Slovic et al. 2016]] ; [[#Khreis--2017|Khreis et al. 2017]] ; [[#Letnik--2018|Letnik et al. 2018]] ). For instance, in coordination with national governments, sub-national actors in China, Europe and USA have introduced access to priority lanes, free parking and other strategies fostering the roll-out of EVs ( [[#Creutzig--2016|Creutzig 2016]] ; [[#Zhang--2017|Zhang and Bai 2017]] ; [[#Teske--2018|Teske et al. 2018]] ; [[#Zhang--2018|Zhang and Qin 2018]] ; [[#Romero-Lankao--2021|Romero-Lankao et al. 2021]] ).

c) Land-use planning addresses building form, density, energy, and transport, which are relevant for decarbonisation ( [[#Creutzig--2015|Creutzig et al. 2015]] ; [[#Torabi%20Moghadam--2017|Torabi Moghadam et al. 2017]] ; [[#Teske--2018|Teske et al. 2018]] ). Its effectiveness is limited by absent or fragmented jurisdiction, financial resources and powers, competition between authorities and policy domains, and national policies that restrict local governments’ ability to enact more ambitious policies ( [[#Fudge--2016|Fudge et al. 2016]] ; [[#Gouldson--2016|Gouldson et al. 2016]] ; [[#Petersen--2016|Petersen 2016]] ). Most rapidly growing smaller cities in Latin America, Asia and Africa lack capacity for urban planning and enforcement ( [[#Romero-Lankao--2015|Romero-Lankao et al. 2015]] ; [[#Creutzig--2016|Creutzig 2016]] ).

d) Other policies: these include information and capacity building, such as carbon labelling aimed at providing carbon footprint information to consumers ( [[#Liu--2016|Liu et al. 2016]] ); disclosure and benchmarking policies in buildings to increase awareness of energy issues and track mitigation progress ( [[#Hsu--2017|Hsu et al. 2017]] ; [[#Papadopoulos--2018|Papadopoulos et al. 2018]] ); and procurement guidelines developed by associations ( [[#Sustainable%20Purchasing%20Leadership%20Council--2021|Sustainable Purchasing Leadership Council 2021]] ). For instance, a building retrofit programme was initiated in New York and Melbourne to foster energy efficiency improvements through knowledge provision, training, and consultation ( [[#Trencher--2016|Trencher et al. 2016]] ; [[#Trencher--2019|Trencher and van der Heijden 2019]] ). Also significant is government provision of public good, services, and infrastructure ( [[#Romero%20Lankao--2019|Romero Lankao et al. 2019]] ), which includes provision of electric buses or buses on renewable fuels for public transportation ( [[#Kamiya--2019|Kamiya and Teter 2019]] ) and zero emission urban freight transport ( [[#Quak--2019|Quak et al. 2019]] ), sustainable food procurement for public organisations in cities ( [[#Smith--2016|Smith et al. 2016]] ), decentralised energy resources ( [[#Marquardt--2014|Marquardt 2014]] ; [[#Hirt--2021|Hirt et al. 2021]] ; [[#Kahsar--2021|Kahsar 2021]] ), and green electricity purchase via community choice aggregation programmes and franchise agreements ( [[#Armstrong--2019|Armstrong 2019]] ).

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=== 13.5.2 Partnerships and Experiments ===

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Partnerships, such as those among private and public, or transnational and sub-national entities, have been found to enable better mitigation results in areas outside direct government control such as residential energy use, emissions from local businesses, or private vehicles ( [[#Fenwick--2012|Fenwick et al. 2012]] ; Castán Broto and [[#Bulkeley--2013|Bulkeley 2013]] ; [[#Aylett--2014|Aylett 2014]] ; [[#Hamilton--2014|Hamilton et al. 2014]] ; [[#Bulkeley--2016|Bulkeley et al. 2016]] ; [[#Wakabayashi--2016|Wakabayashi and Arimura 2016]] ; [[#Grandin--2018|Grandin et al. 2018]] ). Partnerships take advantage of investments that match available grants or enable a local energy project, or enhance the scope or impact of mitigation ( [[#Burch--2013|Burch et al. 2013]] ).

Sub-national actors have also been associated with experiments and laboratories, which promise to achieve the deep change required to address the climate mitigation gap ( [[#Smeds--2018|Smeds and Acuto 2018]] ; [[#Marvin--2018|Marvin et al. 2018]] ). Experiments span smart technologies, for example, in Malmö, Sweden (Parks 2019), Eco-Art, Transformation-Labs and other approaches that question the cultural basis of current energy regimes and seek reimagined or reinvented futures (Castán Broto and [[#Bulkeley--2013|Bulkeley 2013]] ; [[#Guy--2015|Guy et al. 2015]] ; [[#Voytenko--2016|Voytenko et al. 2016]] ; [[#Hodson--2018|Hodson et al. 2018]] ; [[#Peng--2018|Peng and Bai 2018]] ; [[#Smeds--2018|Smeds and Acuto 2018]] ; [[#Culwick--2019|Culwick et al. 2019]] ; [[#Pereira--2019|Pereira et al. 2019]] ; [[#Sengers--2019|Sengers et al. 2019]] ). They may include governance experiments, from formally defined policy experiments to informal initiatives that mobilise new governance concepts ( [[#Kivimaa--2017a|Kivimaa et al. 2017a]] ; [[#Turnheim--2018|Turnheim et al. 2018]] ), and co-design initiatives and grassroots innovations ( [[#Martiskainen--2017|Martiskainen 2017]] ; [[#Sheikh--2021|Sheikh and Bhaduri 2021]] ). These initiatives often expand the scope for citizen participation. For example, Urban Living Labs foster innovation, coproducing responses to existing problems of energy use, energy poverty and mobility that integrate scientific and expert knowledge with local knowledge and common values ( [[#Voytenko--2016|Voytenko et al. 2016]] ; [[#Marvin--2018|Marvin et al. 2018]] ). The European Network of Living Labs – with a global outreach – has established a model of open and citizen-centric innovation for policy making. The proliferation of Climate Assemblies at the national and sub-national level further emphasises the increasing role that citizens can play in both innovating and planning for carbon mitigation ( [[#Sandover--2021|Sandover et al. 2021]] ).

State and local authorities are often central to initiating and implementing experiments and use an incremental, ‘learning by doing’ governing approach ( [[#Bai--2010|Bai et al. 2010]] ; [[#Nevens--2013|Nevens et al. 2013]] ; Castán Broto and [[#Bulkeley--2013|Bulkeley 2013]] ; [[#Mcguirk--2015|Mcguirk et al. 2015]] ; [[#Nagorny-Koring--2018|Nagorny-Koring and Nochta 2018]] ; [[#Hodson--2018|Hodson et al. 2018]] ; [[#Peng--2018|Peng and Bai 2018]] ; [[#Smeds--2018|Smeds and Acuto 2018]] ; [[#Culwick--2019|Culwick et al. 2019]] ; [[#Sengers--2019|Sengers et al. 2019]] ). Experiments relate to technological learning and changes in policies, practices, services, user behaviour, business models, institutions, and governance (Castán Broto and [[#Bulkeley--2013|Bulkeley 2013]] ; [[#Wieczorek--2015|Wieczorek et al. 2015]] ; [[#Kivimaa--2017a|Kivimaa et al. 2017a]] ; [[#Laurent--2018|Laurent and Pontille 2018]] ; [[#Torrens--2019|Torrens et al. 2019]] ).

Experimentation has contributed to learning, changes in outcomes when implemented, and shifts in the political landscape ( [[#Turnheim--2018|Turnheim et al. 2018]] ). Experiments, however, are often isolated and do not always result in longer-term, more widespread changes. The transformative potential (understood as changes in the fundamental attributes of natural and human systems, see Annex I: Glossary) of experiments is constrained by uncertainty about locally relevant climate change solutions and effects; a lack of comprehensive, and sectorally inclusive national policy frameworks for decarbonisation; budgetary and staffing limitations; and a lack of institutional and political capacity to deliver integrated and planned approaches ( [[#Evans--2014|Evans and Karvonen 2014]] ; [[#Mcguirk--2015|Mcguirk et al. 2015]] ; [[#Bulkeley--2016|Bulkeley et al. 2016]] ; [[#Voytenko--2016|Voytenko et al. 2016]] ; [[#Wittmayer--2016|Wittmayer et al. 2016]] ; [[#Webb--2017|Webb et al. 2017]] ; [[#Grandin--2018|Grandin et al. 2018]] ; [[#Hölscher--2018|Hölscher et al. 2018]] ; [[#Nagorny-Koring--2019|Nagorny-Koring 2019]] ; [[#Sengers--2019|Sengers et al. 2019]] ).

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=== 13.5.3 Performance and Global Mitigation Impact ===

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The performance of sub-national actors’ mitigation policies have been measured using criteria such as existence of mitigation targets, incentives for mitigation, definition of a baseline, and existence of a monitoring, reporting, and verification procedure ( [[#Hsu--2019|Hsu et al. 2019]] ). Existing evaluations range from small-scale studies assessing the mitigation potential of commitments by sub-national regions, cities and companies in the USA or in 10 high-emitting economies ( [[#Roelfsema--2017|Roelfsema 2017]] ; [[#Hsu--2019|Hsu et al. 2019]] ), to larger studies finding that over 9149 cities worldwide could mitigate 1400 MtCO 2 -eq in 2030 ( [[#Global%20Covenant%20of%20Mayors%20for%20Climate%20and%20Energy--2018|Global Covenant of Mayors for Climate and Energy 2018]] ; [[#Hsu--2018|Hsu et al. 2018]] , 2019). These sub-national mitigation potential estimates vary since a range of approaches exists for accounting for overlaps between sub-national governments and their nested jurisdictions (e.g., states, provinces, and national governments) ( [[#Roelfsema--2018|Roelfsema et al. 2018]] ; [[#Hsu--2019|Hsu et al. 2019]] ). One analysis found that the cities of New York, Berlin, London, Greater Toronto, Boston, and Seattle have achieved on average a 0.27 tCO 2 -eq per capita per year reduction ( [[#Kennedy--2012|Kennedy et al. 2012]] ). [[#Hsu--2020c|Hsu et al. (2020c)]] found that 60% of more than 1000 European cities, representing 6% of the EU’s total emissions, are on track to achieving their targets, reducing more than 51 MtCO 2 -eq. While evidence is limited, there are concerns that implementation challenges persist with city level plans, particularly tied to management of initiatives and engagement of the population ( [[#Messori--2020|Messori et al. 2020]] ).

Whether participation in transnational climate initiatives impacts sub-national governments’ achievement on climate mitigation goals is uncertain. Some find that higher ambition in climate mitigation commitments did not translate into greater mitigation ( [[#Kona--2016|Kona et al. 2016]] ; [[#Hsu--2019|Hsu et al. 2019]] ). Other studies associate participation in networks with increased solar photovoltaic systems (PV) investment ( [[#Khan--2016|Khan and Sovacool 2016]] ; [[#Steffen--2019|Steffen et al. 2019]] ), and with potential to achieve carbon emissions reductions per capita in line with a global 2°C scenario ( [[#Kona--2016|Kona et al. 2016]] ).

Reporting networks may attract high-performing actors, suggesting an artificially high level of cities interested in taking climate action or piloting solutions (self-selection bias) that may not be effective elsewhere (van der Heijden 2018). Many studies present a conservative view of potential mitigation impact because they draw upon publicly reported mitigation actions and exclude sub-national actions that are not reported ( [[#Kuramochi--2020|Kuramochi et al. 2020]] ).

In addition to direct mitigation contributions, climate action partnerships may deliver indirect effects that, while difficult to quantify, ensure long-term change ( [[#Chan--2015|Chan et al. 2015]] ). Experimentation and policy innovation helps to establish best practices ( [[#Hoffmann--2011|Hoffmann 2011]] ); set new norms for ambitious climate action that help build coalitions ( [[#Chan--2015|Chan et al. 2015]] ; [[#Bernstein--2018|Bernstein and Hoffmann 2018]] ); and translate into knowledge sharing or capacity building ( [[#Lee--2012|Lee and Koski 2012]] ; [[#Hakelberg--2014|Hakelberg 2014]] ; [[#Purdon--2015|Purdon 2015]] ; [[#Acuto--2016|Acuto and Rayner 2016]] ). Emergent researchexplores whether, in addition to realising outcomes, mitigation initiatives also provide the resources, skills and networks that governments and other stakeholders currently use to target other development goals ( [[#Shaw--2014|Shaw et al. 2014]] ; [[#Wolfram--2016|Wolfram 2016]] ; [[#Wiedenhofer--2018|Wiedenhofer et al. 2018]] ; [[#Amundsen--2018|Amundsen et al. 2018]] ; [[#Heikkinen--2019|Heikkinen et al. 2019]] ).

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