Editing IPCC:AR6/WGII/Chapter-10 (section)

===== 10.4.6.4.1 Infrastructural adaptation options =====

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The challenge of adapting infrastructure to climate change across Asia is twofold: there are significant infrastructure deficiencies, especially in low-income countries, and key infrastructures are at high risk due to climate change ( [[#Hallegatte--2019|Hallegatte et al., 2019]] ; [[#Lu--2019|Lu, 2019]] ). Infrastructural adaptation options in cities attempt to enable networked energy, water, waste and transportation systems to prepare for, and deal with, climate risks better ( [[#Meerow--2017|Meerow, 2017]] ) through interventions such as improved highways and power plants, climate-resilient housing, improved water infrastructure and so forth ( [[#ADB--2014|ADB, 2014]] ).

* '''Power infrastructure:''' Adaptations in electricity systems include climate-resilient power infrastructure, particularly essential for coastal megacities such as Manila, Mumbai, Bangkok and Ho Chi Minh City ( [[#Meerow--2017|Meerow, 2017]] ; [[#Duy--2019|Duy et al., 2019]] ), which double as regional economic hubs and are home to tens of millions of people. In the Philippines, solar panels at water pumping stations are installed to operate and maintain a minimal capacity to pump water if the electricity grid were to break down ( [[#Stip--2019|Stip et al., 2019]] ).
* '''Water infrastructure:''' Sustainable water supply and resource management are key to urban adaptation through improved water service delivery, wastewater recycling and storm-water diversion ( [[#Deng--2015|Deng and Zhao, 2015]] ; [[#Xie--2017|Xie et al., 2017]] ; [[#Yu--2018d|Yu et al., 2018d]] ). Infrastructure-based adaptation options in urban water management include building water storage facilities, storm-water management and enhancing water quality improving permeability, managing runoff and enabling groundwater recharge. One example is of Shanghai (China), where infrastructural and policy incentives come together to enable adaptation: the city has been divided into 14 water conservancy zones, including 348 polder areas with 2517 km of dykes, 1499 pump stations and 2203 sluices ( [[#Yu--2018d|Yu et al., 2018d]] ). It also depends on a regional inundation control system, flood Early warning system and an emergency plan to deal with flood risk and mitigate waterlogging ( [[#Chen--2018e|Chen et al., 2018e]] ; [[#Yu--2018d|Yu et al., 2018d]] ). Another example is Ho Chi Minh City (Vietnam), where, given significant increases in area at risk of flooding under climate change, the city has invested in storm sewer upgradation, dike works, improving drainage and increasing the height of road embankments and minor bridges ( [[#Storch--2011|Storch and Downes, 2011]] ; [[#ADB--2014|ADB, 2014]] ; [[#Ho--2017|Ho et al., 2017]] ). These infrastructural interventions were complemented by designing an Early warning system to initiate flood mitigation procedures, such as isolating critical electrical and mechanical operating systems from water.
* '''Built infrastructure:''' Current built-infrastructure adaptation interventions are mostly reactive (e.g., strengthening housing units, using sandbags during flooding, storing of food, evacuation) rather than preventive (e.g., relocation, building multi-storey and stronger housing units), mainly due to limited resources within most vulnerable households for investing in proactive measures ( [[#Francisco--2019|Francisco and Zakaria, 2019]] ). For cities in North Asia seeing permafrost thawing, adequate land-use practices, permafrost monitoring, maintenance of infrastructure and engineering solutions (e.g., using thermosiphons) may temporarily offset the negative effects of permafrost degradation in small, economically vital areas, but are unlikely to have an effect beyond the immediate areas ( [[#Shiklomanov--2017b|Shiklomanov et al., 2017b]] ; Streletskiy, 2019). Importantly, thawing permafrost and GHG emissions create feedbacks where emissions amplify warming and drive additional thaw. Reducing these impacts through mitigation will reduce the need for adaptation significantly ( [[#Schaefer--2014|Schaefer et al., 2014]] ).
* '''Infrastructure and technology:''' Several infrastructural options employ technology, such as smart meters, to monitor water usage and service delivery, but these are differentially adopted across Asian sub-regions with higher adoption across East Asia. Examples include: the Yokohama smart city project in Japan, which has been smart eco-urbanism interventions since 2011 (e.g., energy saving and storage infrastructure, wastewater management, behavioural change towards renewable energy and low-carbon transportation) (IUC, 2019); the Tianjin Eco-city mega-project in China, which is testing a range of measures to meet urban sustainability goals in partnership with Singapore ( [[#ICLEI--2014b|ICLEI, 2014b]] ; [[#Blok--2015|Blok and Tschötschel, 2015]] ); development in New Songdo (Republic of Korea), which is experimenting with interventions, such as embedded smart waste management ( [[#Anthopoulos--2017|Anthopoulos, 2017]] ), and national policy initiatives such as the Smart Cities Mission covering 100 cities in India (e.g. technology-enabled water, energy and land management for urban agriculture in Nashik city) ( [[#ICLEI--2014a|ICLEI, 2014a]] ). However, the efficacy of such measures, especially for larger sustainability and climate-change goals, remains to be seen ( [[#ICLEI--2014a|ICLEI, 2014a]] ; [[#ICLEI--2014b|ICLEI, 2014b]] ; [[#Caprotti--2015|Caprotti et al., 2015]] ; [[#Anthopoulos--2017|Anthopoulos, 2017]] ).

Infrastructural measures alone are seldom effective in building urban resilience as seen in the examples of the 2011 floods in Bangkok and the 2005 typhoon in Manila ( [[#Duy--2019|Duy et al., 2019]] ), or projected estimates by [[#Pervin--2020|Pervin et al. (2020)]] who found that structural interventions in existing drainage systems reduce flooding risk by 7–19% in Sylhet (Bangladesh) and Bharatpur (Nepal); however, without proper solid waste management, areas under flood risk could increase to 18.5% in Sylhet and 7.6% in Bharatpur in five years, rendering the infrastructural interventions ineffective over time. While in some cities it is estimated that infrastructural adaptation through ‘hard’ flood protection strategies (e.g., storm surge barriers and floodwalls) is more effective than institutional or ecosystem-based adaptation by 2100, for example, Shanghai. A hybrid approach where hard strategies protect from flood risk, and soft strategies reduce residual risk from hard strategies, is suggested ( [[#Du--2020|Du et al., 2020]] ). In Japan, without adaptation, estimated damage costs of floods (caused by tropical cyclones and altered precipitation) by 2081–2100 under RCP2.6 will be 28% higher (compared with 1981–2000), rising to 57% higher under RCP8.5 ( [[#Yamamoto--2021|Yamamoto et al., 2021]] ). With a combination of adaptation measures (such as land-use control, piloti building and flood control measures), estimated damage costs can be reduced even below the 1981–2000 levels, and with a combination of mitigation and these adaptation measures, an estimated 69% reduction in flood damage costs are expected–demonstrating the importance of concerted and immediate climate action in reducing damage.

Infrastructural interventions can sometimes be maladaptive when assessed over longer time periods: for example, the Mumbai Coastal Road (MCR) project aimed at reducing flood risk and protecting against SLR will potentially cause damages to intertidal fauna and flora and local fishing livelihoods ( [[#Senapati--2017|Senapati and Gupta, 2017]] ); and Jakarta’s Great Garuda project aimed at reducing flood risk is expected to ''increase'' flood risk for the poorest urban dwellers ( [[#Salim--2019|Salim et al., 2019]] ).

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