Editing IPCC:AR6/WGIII/Chapter-17 (section)

==== 17.3.3.4 Cities, Infrastructure and Transportation ====

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With 80% of the global population expected to be urban by 2050, cities will shape development paths for the foreseeable future ( [[#United%20Nations--2018|United Nations 2018]] ). The challenge for many policymakers is to construct development paths that make cities clean, prosperous and liveable while mitigating climate change and building resilience to heatwaves, flooding and other climate risks. The IPCC SR1.5 report sees achieving these objectives as feasible: cities could potentially realise significant climate and sustainable-development benefits from shifting development paths ( [[#Wiktorowicz--2018|Wiktorowicz et al. 2018]] ). This section assesses the synergies and trade-offs between meeting the SDGs and climate change mitigation, as well as providing a general overview of mitigation options in cities and of enabling factors, including city networks and plans for jointly addressing the SDGs and climate change mitigation.

[[IPCC:Wg3:Chapter:Chapter-8|Chapter 8]] concludes that urban areas potentially offer several joint benefits between mitigation and the SDGs, and that since AR5, evidence of the co-benefits of urban mitigation continues to grow. In developing countries, a co-benefits approach that frames climate objectives alongside other development benefits arise increasingly being seen as an important concept justifying and driving climate change actions in developing countries ( [[#Sethi--2018|Sethi and Puppum De Oliveria 2018]] ; [[#Seto--2016|Seto et al. 2016]] ).

Evidence of the co-benefits of urban mitigation measures on human health has increased significantly since the IPCC AR5, especially through the use of health-impact assessments in cities like Geneva, where energy savings and cleaner energy-supply structures based on measures for urban planning, heating and transport have reduced CO 2 , NO x and PM 10 emissions and increased the opportunities for physical activity for the prevention of cardiovascular diseases ( [[#Diallo--2016|Diallo et al. 2016]] ).

There is increasing evidence that climate-mitigation measures can lower health risks that are related to energy poverty, especially in vulnerable groups, such as the elderly ( [[#Monforti-Ferrario--2019|Monforti-Ferrario et al. 2019]] ). Moreover, the use of urban forestry and green infrastructure as both a climate mitigation and an adaptation measure can reduce heat stress ( [[#Kim--2019|Kim and Coseo 2019]] ; [[#Privitera--2017|Privitera and La Rosa 2017]] ) while removing air pollutants to improve air quality ( [[#Scholz--2018|Scholz et al. 2018]] ; [[#De%20la%20Sota--2019|De la Sota et al. 2019]] ) and enhancing well-being, including contributions to local development and possible reductions of inequalities ( [[#Lwasa--2015|Lwasa et al. 2015]] ). Other studies evidence the potential to reduce premature mortality by up to 7000 in 53 towns and cities, to create 93,000 net new jobs and lower global climate costs, as well as reduce personal energy costs based on road maps for renewable-energy transformations ( [[#Jacobson--2018|Jacobson et al. 2018]] ).

The co-benefits of energy-saving measures described by 146 signatories to a city climate network due to improved air quality have been quantified as 6596 avoided premature deaths (with a 95% confidence interval of 4356 to 8572 avoided premature deaths) and 68,476 years of life saved (with a 95% confidence interval of 45,403 and 89,358 years of life saved) ( [[#Monforti-Ferrario--2019|Monforti-Ferrario et al. 2019]] ). Better air quality further reinforces the health co-benefits of climate-mitigation measures based on walking and cycling, since the evidence suggests that increased physical activity in urban outdoor settings with low levels of black carbon improves lung function ( [[#Laeremans--2018|Laeremans et al. 2018]] ). [[IPCC:Wg3:Chapter:Chapter-9|Chapter 9]] shows that mitigation actions in buildings have multiple co-benefits resulting in substantial social and economic value beyond their direct impacts on reducing energy consumption and GHG emissions, thus contributing to the achievement of almost all the UN’s SDGs. Most studies agree that the value of these multiple benefits is greater than the value of the energy savings, while their quantification and inclusion in decision-making processes will strengthen the adoption of ambitious reduction targets and improve coordination across policy areas.

There are several examples of cities that have developed plans for meeting both the SDGs and mitigation, which demonstrates the feasibility of meeting these objectives jointly. Quito, Ecuador, a city with large carbon footprints ( [[#Global%20Opportunity%20Explorer--2019|Global Opportunity Explorer 2019]] ) and climate vulnerabilities, has adopted low-carbon plans that aim to achieve the climate goals while introducing net-zero energy buildings and reducing water stress ( [[#Ordoñez--2019|Ordoñez et al. 2019]] ; [[#Marcotullio--2018|Marcotullio et al. 2018]] ). Several cities in China, Indonesia and Japan have invested in green-city initiatives by means of green infrastructural investments, which is claimed to be a form of smart investment. Through this type of investment, economic growth and greenhouse gas (GHG) emissions reductions can be achieved in cities ( [[#Jupesta--2016|Jupesta et al. 2016]] ). Multi-level governance arrangements, public-private cooperation and robust urban-data platforms are among the factors enabling the pursuit of these objectives within countries ( [[#Corfee-Morlot--2009|Corfee-Morlot et al. 2009]] ; [[#Gordon--2015|Gordon 2015]] ; [[#Creutzig--2019|Creutzig et al. 2019]] ; [[#Yarime--2017|Yarime 2017]] ).

In addition to the mostly domestic enablers listed previously, some cities have also benefited from working with international networks. The Global Covenant of Mayors for Climate &amp; Energy ( [[#Covenant%20of%20Mayors--2019|Covenant of Mayors 2019]] ), the World Mayors Council on Climate Change, ECLEI, C40, and UNDRR ( [[#C40%20Cities--2019|C40 Cities 2019]] ; [[#ECLEI--2019|ECLEI 2019]] ; [[#UNDRR--2019|UNDRR 2019]] ) have provided targeted support, disseminated information and tools, and sponsored campaigns (Race to Zero) to motivate cities to embrace climate and sustainability objectives. Despite this support, it should be stressed that most cities are in the early stages of climate planning ( [[#Eisenack--2013|Eisenack and Reckien 2013]] ; [[#Reckien--2018|Reckien et al. 2018]] ; [[#Climate-ADAPT--2019|Climate-ADAPT 2019]] ). Furthermore, in some cases city policymakers may fail to highlight the synergies and trade-offs between climate and sustainable development or rebrand GHG-intensive practices as ‘sustainable’ in relevant plans ( [[#Tozer--2018|Tozer 2018]] ).

With regard to city networks, [[IPCC:Wg3:Chapter:Chapter-8#8.5|Section 8.5]] concludes that the importance of urban-scale policies for sustainability has increasingly been recognised by international organisations and national and regional governments. For example, in 2015, more than 150 national leaders adopted the UN’s 2030 Sustainable Development Agenda, including stand-alone SDG 11 (sustainable cities and communities) (UN 2015 p. 14). The following year, 170 countries agreed to the UN New Urban Agenda (NUA), a central part of which is recognising the importance of national urban policies (NUPs) as a key to achieving national economic, social and environmental goals ( [[#United%20Nations--2015a|United Nations 2015a]] 2017). Similarly, the Sendai Framework for Disaster Risk Reduction identifies the need to focus on unplanned and rapid urbanisation to reduce exposure and vulnerability to the risks of disasters ( [[#United%20Nations--2015b|United Nations 2015b]] ).

For many cities, a key to reorienting development paths will be investing in sustainable, low-carbon infrastructure. Because infrastructure has a long lifetime and influences everything from lifestyle choices to consumption patterns, decisions over an estimated USD90 trillion of infrastructure investment (from now to 2030) will be critical in order to avoid becoming locked-in to unsustainable paths ( [[#WRI--2016|WRI 2016]] ). This is particularly true in developing countries, where demands for new buildings, roads, energy and waste-management systems are already surging. To some extent, policies that accelerate building renovation rates, including voluntary programmes (Van der Heijden 2018), can support transitions down more sustainable paths ( [[#Kuramochi--2018|Kuramochi et al. 2018]] ). Factoring climate and sustainable development considerations into policy tools that facilitate the quantitative emission performance standard (EPS) and the inclusion of climate and sustainable development benefits and risks in infrastructure assessments or risk-adjusted returns on investments in development banks could also prove useful ( [[#Rydge--2015|Rydge et al. 2015]] ). Strong policy signals from the UNFCCC and from national climate policies and strategies (including NDCs) could facilitate uptake of the relevant policies and the use of these tools.

Infrastructural investments will also have wide-ranging implications for sustainable, low-carbon urban development, namely transport and mobility. To some extent, decision-making frameworks such as Avoid-Shift-Improve (ASI) could help make these patterns low carbon and sustainable ( [[#Dalkmann--2007|Dalkmann and Brannigan 2007]] ; [[#Wittneben--2009|Wittneben et al. 2009]] ). Mixed land-use planning and compact cities can not only help avoid emissions or shift travellers into cleaner modes ( [[#Cervero--2009|Cervero 2009]] ), they can also improve air quality, reduce commuting times, enhance energy security and improve connectivity ( [[#Zusman--2011|Zusman et al. 2011]] ; [[#Pathak--2016|Pathak and Shukla 2016]] ).

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