Editing IPCC:AR6/SR15/Chapter-5 (section)

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====== Lead Authors ======

* Fernando Aragón-Durand (Mexico)
* Paolo Bertoldi (Italy)
* Anton Cartwright (South Africa)
* Francois Engelbrecht (South Africa)
* Bronwyn Hayward (New Zealand)
* Daniela Jacob (Germany)
* Debora Ley (Guatemala, Mexico)
* Shagun Mehrotra (United States, India)
* Peter Newman (Australia)
* Aromar Revi (India)
* Seth Schultz (United States)
* William Solecki (United States)
* Petra Tschakert (Australia, Austria)

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====== Contributing Authors ======

* Peter Marcotullio (United States)

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'''Global Urbanization in a 1.5°C Warmer World'''

The concentration of economic activity, dense social networks, human resource capacity, investment in infrastructure and buildings, relatively nimble local governments, close connection to surrounding rural and natural environments, and a tradition of innovation provide urban areas with transformational potential (see Chapter 4, Section 4.3.3) (Castán Broto, 2017) <sup>[[#fn:r400|400]]</sup> . In this sense, the urbanization megatrend that will take place over the next three decades, and add approximately 2 billion people to the global urban population (UN, 2014) <sup>[[#fn:r401|401]]</sup> , offers opportunities for efforts to limit warming to 1.5°C.

Cities can also, however, concentrate the risks of flooding, landslides, fire and infectious and parasitic disease that are expected to heighten in a 1.5°C warmer world (Chapter 3). In African and Asian countries where urbanization rates are highest, these risks could expose and amplify pre-existing stresses related to poverty, exclusion, and governance (Gore, 2015; Dodman et al., 2017; Jiang and O’Neill, 2017; Pelling et al., 2018; Solecki et al., 2018) <sup>[[#fn:r402|402]]</sup> . Through its impact on economic development and investment, urbanization often leads to increased consumption and environmental degradation and enhanced vulnerability and risk (Rosenzweig et al., 2018) <sup>[[#fn:r403|403]]</sup> . In the absence of innovation, the combination of urbanization and urban economic development could contribute 226 GtCO <sub>2</sub> in emissions by 2050 (Bai et al., 2018) <sup>[[#fn:r404|404]]</sup> . At the same time, some new urban developments are demonstrating combined carbon and Sustainable Development Goals (SDG) benefits (Wiktorowicz et al., 2018) <sup>[[#fn:r405|405]]</sup> , and it is in towns and cities that building renovation rates can be most easily accelerated to support the transition to 1.5°C pathways (Kuramochi et al., 2018) <sup>[[#fn:r406|406]]</sup> , including through voluntary programmes (Van der Heijden, 2018) <sup>[[#fn:r407|407]]</sup> .

'''Urban transformations and emerging climate-resilient development pathways'''

The 1.5°C pathways require action in all cities and urban contexts. Recent literature emphasizes the need to deliberate and negotiate how resilience and climate-resilient pathways can be fostered in the context of people’s daily lives, including the failings of everyday development such as unemployment, inadequate housing and a growing informal sector and settlements (informality), in order to acknowledge local priorities and foster transformative learning (Vale, 2014; Shi et al., 2016; Harris et al., 2017; Ziervogel et al., 2017; Fazey et al., 2018; Macintyre et al., 2018) <sup>[[#fn:r408|408]]</sup> . Enhancing deliberate transformative capacities in urban contexts also entails new and relational forms of envisioning agency, equity, resilience, social cohesion and well-being (Section 5.5.3) (Gillard et al., 2016; Ziervogel et al., 2016) <sup>[[#fn:r409|409]]</sup> . Two examples of urban transformation are explored here.

The built environment, spatial planning, infrastructure, energy services, mobility and urban–rural linkages necessary in '''rapidly growing cities in South Asia and Africa''' in the next three decades present mitigation, adaptation and development opportunities that are crucial for a 1.5°C world (Newman et al., 2017; Lwasa et al., 2018; Teferi and Newman, 2018) <sup>[[#fn:r410|410]]</sup> . Realizing these opportunities would require the structural challenges of poverty, weak and contested local governance, and low levels of local government investment to be addressed on an unprecedented scale (Wachsmuth et al., 2016; Chu et al., 2017; van Noorloos and Kloosterboer, 2017; Pelling et al., 2018) <sup>[[#fn:r411|411]]</sup> .

Urban governance is critical to ensuring that the necessary urban transitions deliver economic growth and equity (Hughes et al., 2018) <sup>[[#fn:r412|412]]</sup> . The proximity of local governments to citizens and their needs can make them powerful agents of climate action (Melica et al., 2018) <sup>[[#fn:r413|413]]</sup> , but urban governance is enhanced when it involves multiple actors (Ziervogel et al., 2016; Pelling et al., 2018) <sup>[[#fn:r414|414]]</sup> , supportive national governments (Tait and Euston-Brown, 2017) <sup>[[#fn:r415|415]]</sup> , and sub-national climate networks (see Chapter 4, Section 4.4.1). Governance is complicated for the urban population currently living in informality. This population is expected to triple, to three billion, by 2050 (Satterthwaite et al., 2018) <sup>[[#fn:r416|416]]</sup> , placing a significant portion of the world’s population beyond the direct reach of formal climate mitigation and adaptation policies (Revi et al., 2014) <sup>[[#fn:r417|417]]</sup> . How to address the co-evolved and structural conditions that lead to urban informality and associated vulnerability to 1.5°C of warming is a central question for this report. Brown and McGranahan (2016) <sup>[[#fn:r418|418]]</sup> cite evidence that the informal urban ‘green economy’ that has emerged out of necessity in the absence of formal service provisions is frequently low-carbon and resource-efficient.

Realising the potential for low carbon transitions in informal urban settlements would require an express recognition of the unpaid-for contributions of women in the informal economy, and new partnerships between the state and communities (Ziervogel et al., 2017; Pelling et al., 2018; Satterthwaite et al., 2018) <sup>[[#fn:r419|419]]</sup> . There is no guarantee that these partnerships will evolve or cohere into the type of service delivery and climate governance system that could steer the change on a scale required to limit to warming to 1.5°C (Jaglin, 2014) <sup>[[#fn:r420|420]]</sup> . However, work by transnational networks, such as Shack/Slum Dwellers International, C40, the Global Covenant of Mayors, and the International Council for Local Environmental Initiatives, as well as efforts to combine in-country planning for Nationally Determined Contributions (NDCs) (Andonova et al., 2017; Fuhr et al., 2018) <sup>[[#fn:r421|421]]</sup> with those taking place to support the New Urban Agenda and National Urban Policies, represent one step towards realizing the potential (Tait and Euston-Brown, 2017) <sup>[[#fn:r422|422]]</sup> . So too do ‘old urban agendas’, such as slum upgrading and universal water and sanitation provision (McGranahan et al., 2016; Satterthwaite, 2016; Satterthwaite et al., 2018) <sup>[[#fn:r423|423]]</sup> .

'''Transition Towns (TTs)''' are a type of urban transformation that have emerged mainly in high-income countries. The grassroots TT movement (origin in the United Kingdom) combines adaptation, mitigation and just transitions, mainly at the level of communities and small towns. It now has more than 1,300 registered local initiatives in more than 40 countries (Grossmann and Creamer, 2017) <sup>[[#fn:r424|424]]</sup> , many of them in the United Kingdom, the United States, and other high-income countries. TTs are described as ‘progressive localism’ (Cretney et al., 2016) <sup>[[#fn:r425|425]]</sup> , aiming to foster a ‘communitarian ecological citizenship’ that goes beyond changes in consumption and lifestyle (Kenis, 2016) <sup>[[#fn:r426|426]]</sup> . They aspire to promote equitable communities resilient to the impacts of climate change, peak oil and unstable global markets; re-localization of production and consumption; and transition pathways to a post-carbon future (Feola and Nunes, 2014; Evans and Phelan, 2016; Grossmann and Creamer, 2017) <sup>[[#fn:r427|427]]</sup> .

TT initiatives typically pursue lifestyle-related low-carbon living and economies, food self-sufficiency, energy efficiency through renewables, construction with locally sourced material and cottage industries (Barnes, 2015; Staggenborg and Ogrodnik, 2015; Taylor Aiken, 2016) <sup>[[#fn:r428|428]]</sup> . Social and iterative learning through the collective involves dialogue, deliberation, capacity building, citizen science engagements, technical re-skilling to increase self-reliance, for example canning and preserving food and permaculture, future visioning and emotional training to share difficulties and loss (Feola and Nunes, 2014; Barnes, 2015; Boke, 2015; Taylor Aiken, 2015; Kenis, 2016; Mehmood, 2016; Grossmann and Creamer, 2017) <sup>[[#fn:r429|429]]</sup> .

Important conditions for successful transition groups include flexibility, participatory democracy, care ethics, inclusiveness and consensus-building, assuming bridging or brokering roles, and community alliances and partnerships (Feola and Nunes, 2014; Mehmood, 2016; Taylor Aiken, 2016; Grossmann and Creamer, 2017) <sup>[[#fn:r430|430]]</sup> . Smaller scale rural initiatives allow for more experimentation (Cretney et al., 2016) <sup>[[#fn:r431|431]]</sup> , while those in urban centres benefit from stronger networks and proximity to power structures (North and Longhurst, 2013; Nicolosi and Feola, 2016) <sup>[[#fn:r432|432]]</sup> . Increasingly, TTs recognize the need to participate in policymaking (Kenis and Mathijs, 2014; Barnes, 2015) <sup>[[#fn:r433|433]]</sup> .

Despite high self-ratings of success, some TT initiatives are too inwardly focused and geographically isolated (Feola and Nunes, 2014) <sup>[[#fn:r434|434]]</sup> , while others have difficulties in engaging marginalized, non-white, non-middle-class community members (Evans and Phelan, 2016; Nicolosi and Feola, 2016; Grossmann and Creamer, 2017) <sup>[[#fn:r435|435]]</sup> . In the United Kingdom, expectations of innovations growing in scale (Taylor Aiken, 2015) <sup>[[#fn:r436|436]]</sup> and carbon accounting methods required by funding bodies (Taylor Aiken, 2016) <sup>[[#fn:r437|437]]</sup> undermine local resilience building. Tension between explicit engagements with climate change action and efforts to appeal to more people have resulted in difficult trade-offs and strained member relations (Grossmann and Creamer, 2017) <sup>[[#fn:r438|438]]</sup> though the contribution to changing an urban culture that prioritizes climate change is sometimes underestimated (Wiktorowicz et al., 2018) <sup>[[#fn:r439|439]]</sup> .

Urban actions that can highlight the 1.5°C agenda include individual actions within homes (Werfel, 2017; Buntaine and Prather, 2018) <sup>[[#fn:r440|440]]</sup> ; demonstration zero carbon developments (Wiktorowicz et al., 2018) <sup>[[#fn:r441|441]]</sup> ; new partnerships between communities, government and business to build mass transit and electrify transport (Glazebrook and Newman, 2018) <sup>[[#fn:r442|442]]</sup> ; city plans to include climate outcomes (Millard-Ball, 2013) <sup>[[#fn:r443|443]]</sup> ; and support for transformative change across political, professional and sectoral divides (Bai et al., 2018) <sup>[[#fn:r444|444]]</sup> .

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