Editing IPCC:AR6/WGII/Chapter-6 (section)

=== 6.2.6 Impacts and Risks of Urban Adaptation Actions ===

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Planning and implementing climate adaptation in cities and settlements can be hampered by incomplete scientific knowledge, a lack of awareness of cascading impacts (and residual risks), mismanagement of actions, human capacity and financing deficits, as well as opportunities for eroding long-term sustainable development priorities (Juhola et al., 2016). These tensions can become acute in fragile and conflict affected states (see Box 6.3). It is important to differentiate between the climatic drivers of risk and social drivers that may compound risk exposures and experiences ( [[#Brown--2014|Brown, 2014]] ; Nightingale et al., 2020), especially since technically- and scientifically-informed adaptation actions can be redirected depending on socioeconomic, political or cultural conditions on the ground (Eriksen, Nightingale and Eakin, 2015). The implementation of adaptation, whether by government, private sector or civil society actors, can therefore lead to unanticipated and unintended amplification of political, economic and ecological risks (Swatuk et al., 2020). Many cities are still in the phase of piloting or testing out appropriate adaptation actions, although there is emerging consensus that adaptation plans and projects should acknowledge trade-offs, intentionally avoid past development mistakes, not lock-in detrimental impacts or further risks arising from implementation and explicitly anticipate the risks of maladaptation in decision making (Magnan et al., 2016; Gajjar, Singh and Deshpande, 2019). Maladaptation describes actions that lead to increased vulnerability or risk to climate impacts or diminish welfare. Urban examples include green gentrification which offers nature-based solutions to the few, social safety nets that promote risk inducing subsidies. Whether an action is maladapted can depend on context, for example air conditioning can reduce risk for the individual but is maladaptive at a societal level (see [[#6.3.4.2|Section 6.3.4.2]] ). It is informed by process; corruption can distort processes and generate maladaptation (see [[#6.4.5.2|Section 6.4.5.2]] ). Climate resilient development raises the ambition for adaptation actions so that it is also possible to describe actions that do not also enhance climate mitigation and sustainable development outcomes as maladaptive (see [[#6.4.3.1|Section 6.4.3.1]] ). This section assesses three broad categories of risk arising from downstream adaptation actions, including interventions that transfer vulnerability across space and time, plans that yield socioeconomically exclusionary outcomes, and actions that undermine long-term sustainable and resilient development priorities.

Downstream impacts occur because adaptive capacity is often unequally distributed across sectors and communities (Matin, Forrester and Ensor, 2018; [[#Makondo--2018|Makondo and Thomas, 2018]] ). In cities and settlements, adaptation interventions can displace ecological impacts to more vulnerable areas or directly lead to socioeconomically exclusionary outcomes (Anguelovski et al., 2016), particularly when adaptation plans and actions are primarily assessed through the prism of economic and/or financial viability (Shi et al., 2016; Klein, Juhola and Landauer, 2017). As a result, adaptation actions make only minimal contributions to the reduction of vulnerability, as the increased vulnerability of excluded communities more than offsets the decreased vulnerability of more well-off communities. Numerous examples, ranging from the mega coastal planning in Jakarta, Indonesia (Salim, Bettinger and Fisher, 2019; [[#Goh--2019|Goh, 2019]] ), fragmentation of urban infrastructure intended to promote climate resilience in Manila, Philippines ( [[#Meerow--2017|Meerow, 2017]] ), exclusionary modes of flood control in São Paulo, Brazil ( [[#Henrique--2019|Henrique and Tschakert, 2019]] ), strategies to reduce risks in the event of mudslides in Sarno, Italy ( [[#D’Alisa--2016|D’Alisa and Kallis, 2016]] ), and involuntary community relocations in Vietnam ( [[#Lindegaard--2020|Lindegaard, 2020]] ) and Mozambique ( [[#Arnall--2019|Arnall, 2019]] ) all point to how an economic logic to adaptation can lead to exclusion of lower income, informal or minority communities in adaptation.

A specific form of maladaptation is so-called green gentrification, this privileges wealthy urban residents in urban greening projects (Rice et al., 2020; Shokry, Connolly and Anguelovski, 2020; Anguelovski, Irazábal-Zurita and Connolly, 2019; [[#Blok--2020|Blok, 2020]] ). For example, in Miami-Dade County, Florida, USA, researchers found that adaptation functionality had a positive effect on property values (Keenan, Hill and Gumber, 2018). In New York City and Atlanta, Georgia, USA, research has shown that adaptation investments can increase property values and lead to neighbourhood change ( [[#Immergluck--2018|Immergluck and Balan, 2018]] ; [[#Gould--2018|Gould and Lewis, 2018]] ). In the Gold Coast and Sunshine Coast, South East Queensland, Australia, where local communities have a strong preference for waterfront living, local governments are pressured by property developers to protect these coastal zones (Torabi, Dedekorkut-Howes and Howes, 2018). In Lagos, Nigeria, efforts to achieve climate resilience and sustainability through future city practices risk perpetuating the enclosure and commodification of land ( [[#Ajibade--2017|Ajibade, 2017]] ). The exclusionary outcomes of some adaptation interventions can therefore further heighten the risk to communities that are socioeconomically more vulnerable. See [[#6.3|Section 6.3]] for further discussion of equity and justice considerations in local climate adaptation.

Human behaviour can exacerbate climate impacts, for example in the emergence of ‘last chance tourism’, Lemieux et al. (2018) focused on built cultural heritage at risk from climate change associated events, including from decay or even total loss generated by increased flooding and sea level rise (Camuffo, Bertolin and Schenal, 2017) and water infiltration from post-flood standing water ( [[#Camuffo--2019|Camuffo, 2019]] ). Last chance tourism can lead to increased touristic interest over a short time horizon and to precarious economic conditions, which can lead to further accelerated degradation cultural heritage sites already at risk from climate change.

Finally, some adaptation policies or actions can erode the preconditions for sustainable and resilient development by indirectly increasing society’s vulnerability (Neset et al., 2019; Juhola et al., 2016). Mandates to mainstream adaptation into existing development logics and structures perpetuates development-as-usual, reinforcing technocratic forms of local governance and locking in structural causes of marginalisation and differential vulnerability (Scoville-Simonds, Jamali and Hufty, 2020). Adaptation policy examples include: Australia’s adaptation policy focus on financial strategies, preference for business-as-usual scenarios and incremental change will not contribute to transformative change ( [[#Granberg--2014|Granberg and Glover, 2014]] ); Surat, India, where a focus on adapting industries and economically important assets in the city can divert policy attention away from general social equity and urban sustainability priorities ( [[#Chu--2016|Chu, 2016]] ; [[#Blok--2020|Blok, 2020]] ); Cambodia, where conflict between adaptation practitioners and local communities and non-compliance with regulatory safeguards led to conflict and potential for maladaptation (Work et al., 2018). Finally, although insurance has the potential to incentivise practices to reduce risks, including through measures to reduce premiums (see [[#6.4.5|Section 6.4.5]] for additional details), researchers of insurance-led adaptation actions have argued that, since insurance regimes privilege normality, they tend to structurally embed risky behaviour and inhibit change (O’Hare, White and Connelly, 2016). All of these examples illustrate how incremental strategies that rely on business-as-usual actions can further entrench unequal and unsustainable development patterns in the long term. There are also significant limits to urban adaptation (see [[#6.4|Section 6.4]] ) with consequential impacts on human well-being.

Table 6.4 lists a selection of key risks (broadly defined as have severe outcomes common to a majority of cities) identified in our assessment of urban impacts and risks in this section. It provides a description of the consequences of the risk that would constitute a severe outcome, as well as the hazard, exposure and vulnerability conditions contributing to its severity. It also provides adaptation options identified and elaborated on in [[#6.3|Section 6.3]] as having the highest potential for reducing the risk, and an assessment of the confidence in the judgement that this risk could become severe. This table is also reflected in [[IPCC:Wg2:Chapter:Chapter-16#16.5.1|Section 16.5.1]] , and the methodology is described in Table SM16.5.1.

'''Table 6.4 |''' Key Risks to cities, settlements and infrastructure

{| class="wikitable"
|-
! colspan="7"| Synthesis of key risks for cities, settlements and key infrastructure

!
|-
! Key risk

! Geographic region

! Consequence that would be considered severe, and to whom.

! Hazard conditions that would contribute to this risk being severe.

! Exposure conditions that would contribute to this risk being severe.

! Vulnerability conditions that would contribute to this risk being severe.

! Adaptation options with highest potential for reducing risk.

! Confidence in key risk identification.

! Chapter and section

|-
| Risk to population from increased heat

| Global but higher risk in temperate and tropical cities. (6.2.3.1)

| Increased heat stress, mortality and morbidity events from urbanisation and climate change.

Increased health risks and mortality in elderly population;

vulnerability of the young to heat. (6.2.3.1)

| Substantial increase in frequency and duration of extreme heat events, exacerbated by urban heat island effects. (6.2.3.1)

Concentration of a mixture of extreme heat and humidity. (6.2.3.1)

| Large increases in exposure, particularly in urban areas, (6.2.3) driven by population growth, changing demographics, and projected urbanisation patterns.

Urbanisation increases annual mean surface air temperature by more than 1°C

Correlation between rising temperatures and increased heat capacity of urban structures, anthropogenic heat release and reduced urban evaporation. (6.2.3.1)

| Changing demographics from aging populations, potential for persistent poverty, slow penetration and increasing cost of air conditioning, and inadequate improvements in public health systems.

(6.2.3.1)

Inadequate housing and occupations with exposure to heat. (6.2.3.1)

| Nature-based solutions e.g., urban greenery at multiple spatial scales; vegetation; shading; lower energy costs; green roofs; community gardens; (6.3.3.1) enhanced space conditioning in buildings; broader access to public health systems for most vulnerable populations.

Less economic stress on residents through utilities, especially electricity. (6.2.3.1)

Tree planting in communities that lack urban greening. (6.3.3.1)

| ''High confidence'' , robust ''evidence'' and high ''agreement'' .

| 6.2, 6.3

|-
| Urban infrastructure at risk of damage from flooding and severe storms

| Global, but higher risk in coastal cities.

| Damage to key urban infrastructure (e.g., buildings, transport networks, and power plants) and services from flood events, particularly high risk within coastal cities, especially those located in low elevation coastal zones. (6.2.3.2)

| Substantial increase in frequency and intensity of extreme precipitation (6.2.3.2) from severe weather events and tropical cyclones contributing to pluvial and fluvial floods, which are exacerbated by long-term sea level rise and potential land subsidence. (6.2.3.2)

| Large increases in exposure, particularly in urban areas, driven by population growth, changing demographics, and projected urbanisation patterns with a geographical focus in coastal regions. Flooding is exacerbated both by encroachment of urban areas into areas that retain water, and lack of infrastructure such as embankments and flood walls. (6.2.3.2)

| Costly maintenance of protective infrastructure, downstream levee effects, and increased concentrations of coastal urban population. Little investment in drainage solutions. (6.2.3.2)

| Early warning systems, Adaptive Social Protection (ASP) to reduce vulnerable populations, nature-based solutions e.g., in sponge cities to enhance flood protection and regulate storm- and floodwaters; this can be improved through reduced risk unto vulnerable urban systems such as stormwater management, sustainable urban drainage system, etc. (6.2.3.2)

Green infrastructure can be more flexible and cost effective for providing flood risk reduction. (6.3.3)

| ''High confidence'' , ''robust evidence'' and high agreement

| 6.2, 6.3, CCP2

|-
| Population at risk from exposure to urban droughts

| Cities located in regions with high drought exposure (e.g., Europe, South Africa, Australia).

| Water shortages in urban areas, and restricted access to water resources to vulnerable populations and low-income settlements. People living in urban areas will be exposed to water scarcity from severe droughts. (6.2.3.3) Increased environmental health risks when using polluted groundwater. (6.2.3.3)

| Projections of more frequent and prolonged drought events potentially compounded with heatwave hazards, and land subsidence from coastal cities that extract groundwater. Climate drivers (warmer temperatures and droughts) along with urbanisation processes (land use changes, migration to cities and changing patterns of water use) contribute to additional risks. (6.2.3.3)

| Large increases in exposure, particularly in urban areas, driven by population growth, changing demographics, and projected urbanisation patterns. Limitations of engineered water infrastructure is also exposed by flash droughts. (6.2.3.3) Settlements are increasingly dependent on imported water resources by locales that may also be exposed to drought risk. (6.2.3.3)

| Greater water demand from urban populations from in-migration and key economic sectors, and inefficient or ineffective water resource management. (6.2.3.3)

| Demand and supply side management strategies that include incorporation of indigenous/local knowledge and practices, equitable access to water. Better water resource management will increase quality of water available. More beneficial physical and social teleconnections to bring mutual benefit of water resources between regions. (6.2.3.3)

| ''High confidence'' , ''robust evidence'' and high agreement

| 6.2, 6.3

|-
| Health risks from air pollution exposure in cities

| Global, in cities located in Africa, South Asia, the Middle East and East Asia

| Increased mortality and morbidity events from respiratory-related illnesses and co-morbidities toward vulnerable urban populations, arising from PM2.5 and tropospheric ozone exposure.

| Increased emissions of pollutants from anthropogenic (e.g., transportation, electric power generation, large industries, indoor burning of fuel, and commercial and residential sources) and biogenic (e.g., forests, windblown dust, and biomass burning) emissions.

Potential for severe compound risks arising from droughts and wildfire.

Projections for frequency of meteorological conditions are expected to severe PM2.5 concentrations. (6.2.3.4)

| Large increases in exposure, particularly in urban areas, driven by population growth, changing demographics, projected urbanisation patterns and demand for energy combined with weak regulations for emissions control. (6.2.2.4)

| High proportion of young or aging populations vulnerable to respiratory illness, potential for persistent poverty, advection of pollutants from upwind, ex-urban areas, and stay in shelter policies from COVID-19. (Box 6.4; 6.2.5)

| Enhanced monitoring of air quality in rapidly developing cities,

investment in air pollution controls, e.g., stricter emissions. regulations, and

increased GHG emissions controls resulting in co-benefits with air quality improvements.

Increase in trees or vegetated barriers with low VOC emissions, low allergen emissions, and high pollutant deposition potential to reduce particulate matter and maximise adaptation benefits. (6.3.3.2)

| ''High confidence'' , ''medium evidence'' and high ''agreement''

| 6.2, 6.3

|-
| Health risks from water pollution exposure and sanitation in cities

| Cities located in regions with high drought exposure resulting in polluted water.

| Increased environmental health risks when using polluted groundwater. (6.2.3.3)

Vulnerability of users such as women; children; the elderly; ill or disabled. (6.3.4.6)

| Decreased regional precipitation and changes in runoff and storage from droughts impairs the quality of water available. Less runoff to freshwater rivers can increase salinity, concentrate pathogens, and pollutants. (6.2.2.3)

| Large increases in exposure, particularly in urban areas, driven by population growth, changing demographics, and projected urbanisation patterns. Low flows from drought can lead to sedimentation, increase pollutant concentration and blocking of sewer infrastructure networks. (6.2.4.8).

| Costly maintenance of protective infrastructure. Sanitation systems coupled with flood water management are at risk of damage and capacity exceedance from high rainfall. (6.2.4.8)

| Investment in well-regulated water sections; wastewater treatment plants; pumping stations. Reducing impacts of floods on sanitation infrastructure through active management such as reducing blockage in sewer infrastructure (6.3.4.6)

Adaptive planning; integration of measures of climate resilience; improved accounting and management of water resources. (6.3.4.6)

| ''High confidence'' , ''medium evidence'' and High agreement

| 6.2, 6.3

|}

Following Chapter 16, the severity of a risk or impact is a subjective judgment based on a number of criteria. Key risks are ‘potentially’ severe because, while some could already be severe now, more typically they may become so over time because of changes in the nature of the climate-related hazards and/or of the exposure and/or vulnerability of societies or ecosystems to those hazards. They also may become severe owing to the adverse consequences of adaptation or mitigation responses to the risk.

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