Editing IPCC:AR6/WGIII/Chapter-8 (section)

=== 8.5.5 Barriers and Enablers for Implementation ===

<div id="h2-29-siblings" class="h2-siblings"></div>

Irrespective of geography or development level, many cities face similar climate governance challenges such as lacking institutional, financial, and technical capacities ( [[#Gouldson--2015|Gouldson et al. 2015]] ; [[#Hickmann--2017|Hickmann and Stehle 2017]] ; [[#Sharifi--2017|Sharifi et al. 2017]] ; [[#Fuhr--2018|Fuhr et al. 2018]] ). Large-scale system transformations are also deeply influenced by factors outside governance and institutions, such as private interests and power dynamics ( [[#Jaglin--2014|Jaglin 2014]] ; [[#Tyfield--2014|Tyfield 2014]] ). In some cases, these private interests are tied up with international flows of capital. At the local level, a lack of empowerment, high upfront costs, inadequate and uncertain funding for mitigation, diverse and conflicting policy objectives, multiple agencies and actors with diverse interests, high levels of informality, and a siloed approach to climate action are constraining factors to mainstreaming climate action ( [[#Beermann--2016|Beermann et al. 2016]] ; [[#Gouldson--2016|Gouldson et al. 2016]] ; [[#Pathak--2018|Pathak and Mahadevia 2018]] ; [[#Khosla--2019|Khosla and Bhardwaj 2019]] ).

Yet urban mitigation options that can be implemented to transform urban systems involve the interplay of multiple enablers and barriers. Based on a framework for assessing feasibility from a multi-dimensional perspective, feasibility is malleable and various enablers can be brought into play to increase the implementation of mitigation options. The scope of this assessment enables an approach for considering multiple aspects that have an impact on feasibility as a tool for policy support ( [[#Singh--2020|Singh et al. 2020]] ). In Figure 8.19, the assessment framework that is based on geophysical, environmental-ecological, technological, economic, socio-cultural, and institutional dimensions is applied to identify the enablers and/or barriers in implementing mitigation options in urban systems. The feasibility of options may differ across context, time, and scale (Section 8.SM.2). The line of sight upon which the assessment is based includes urban case studies ( [[#Lamb--2019|Lamb et al. 2019]] ) and assessments of land use and spatial planning in IPCC SR1.5 ( [[#IPCC--2018a|IPCC 2018a]] ).

Across the enablers and barriers of different mitigation options, urban land use and spatial planning for increasing co-located densities in urban areas has positive impacts in multiple indicators, particularly reducing land use and preserving carbon sinks when the growth in urban extent is reduced and avoided, which if brought into interplay in decision-making, can support the enablers for its implementation. Improvements in air quality are possible when higher urban densities are combined with modes of active transport, electrified mobility as well as urban green and blue infrastructure (Sections 8.3.4, 8.4 and 8.6). The demands on geophysical resources, including materials for urban development, will depend on whether additional strategies are in place with largely negative impacts under conventional practices. The technological scalability of multiple urban mitigation options is favourable while varying according to the level of existing urban development and scale of implementation (Tables 8.SM.3 and 8.SM.4).

Similarly, multiple mitigation options have positive impacts on employment and economic growth, especially when urban densities enable productivity. Possible distributional effects, including availability of affordable accommodation and access to greenspace, are best addressed when urban policy packages combine more than one policy objective. Such an approach can provide greater support to urban mitigation efforts with progress towards shifting urban development to sustainability. The electrification of the urban energy system involves multiple enablers that support the feasibility of this mitigation option, including positive impacts on health and well-being. In addition, increases in urban densities can support the planning of district heating and cooling networks that can decarbonize the built environment at scale with technology readiness levels increasing for lower temperature supply options. Preventing, minimising, and managing waste as an urban mitigation option can be enabled when informality in the sector is transformed to secure employment effects and value-addition based on the more circular use of resources (Sections 8.4.3 and 8.4.5, and Tables 8.SM.3 and 8.SM.4 in Supplementary Material 8.2).

As a combined evaluation, integrating multiple mitigation options in urban systems involves the greatest requirement for strengthening institutional capacity and governance through cross-sectoral coordination. Notably, integrated action requires significant effort to coordinate sectors and strategies across urban growth typologies (Sections 8.4 and 8.6, and Figure 8.21). Institutional capacity, if not strengthened to a suitable level to handle this process – especially to break out of carbon lock-in – can fall short of the efforts this entails. These conditions can pose barriers for realising cross-sectoral coordination while the formation of partnerships and stakeholder engagement take place as important enablers. Overcoming institutional challenges for cross-sectoral coordination can support realising synergies among the benefits that each mitigation option can offer within and across urban systems, including for the SDGs. These include those that can be involved in co-located and walkable urban form together with decarbonising and electrifying the urban energy system as well as urban green and blue infrastructure, providing the basis for more liveable, resource efficient and compact urban development with benefits for urban inhabitants ( [[#8.2|Section 8.2]] ).

<div id="8.6" class="h1-container"></div>

<span id="a-roadmap-for-integrating-mitigation-strategies-for-different-urbanisation-typologies"></span>