Editing IPCC:AR6/WGII/Chapter-14 (section)

=== 14.5.5 Cities, Settlements and Infrastructure ===

<div id="h2-12-siblings" class="h2-siblings"></div>

Cities are complex social–ecological systems with large populations, concentrated wealth, ageing infrastructure, reliance on extrinsic and increasingly stressed natural systems, social inequality, differential institutional capacities and impervious, heat-retaining surfaces ( [[#Maxwell--2018a|Maxwell et al., 2018a]] ; [[#Schell--2020|Schell et al., 2020]] ). These factors interact with location (e.g., proximity to coast, in a floodplain) to create city-specific vulnerabilities to climate change and requirements for resilience initiatives ( [[#Mercer%20Clarke--2016|Mercer Clarke et al., 2016]] ). Cities are home to diverse cultural and social communities, including large Indigenous populations who can be uniquely affected by climate change yet who bring valuable IK and leadership to urban adaptation efforts (Statistics Canada, 2020; [[#Brown--2021|Brown et al., 2021]] ). The rural and remote settlements of North America also experience similar hazards and risks; however, such challenges are due to different factors such as geographic isolation, dependence on local food resources and socioeconomic conditions ( [[#Kearney--2019|Kearney and Bell, 2019]] ; [[#Vodden--2021|Vodden and Cunsolo, 2021]] ).

<div id="14.5.5.1" class="h3-container"></div>

<span id="observed-impacts-1"></span>
==== 14.5.5.1 Observed Impacts ====

<div id="h3-14-siblings" class="h3-siblings"></div>

<div id="14.5.5.1.1" class="h4-container"></div>

<span id="rising-temperatures-and-extreme-heat"></span>
===== 14.5.5.1.1 Rising temperatures and extreme heat =====

<div id="h4-4-siblings" class="h4-siblings"></div>

Extreme heat events are affecting natural assets and built infrastructure as well as individuals in cities and rural settlements across North America ( ''high confidence'' ) (Maria Raquel et al., 2016; [[#Amec%20Foster%20Wheeler%20and%20Credit%20Valley%20Conservation--2017|Amec Foster Wheeler and Credit Valley Conservation, 2017]] ; [[#Howell--2019|Howell and Brady, 2019]] ; [[#Martinich--2019|Martinich and Crimmins, 2019]] ). Key urban infrastructure systems (e.g., services in buildings, energy distribution) are interdependent and susceptible to cascading impacts (e.g., electricity supply disruption during a heatwave compromising another system like water delivery, high-rise cooling) ( [[#Brown--2021|Brown et al., 2021]] ). Urban social inequality and systemic racism has led to disproportionately higher exposure to urban heat island effects in low-income and minority neighbourhoods in US cities, due in part, to less green space and tree cover to offset heat retained in the built environment ( [[#Hoffman--2020|Hoffman et al., 2020]] ; [[#Schell--2020|Schell et al., 2020]] ; [[#Hsu--2021|Hsu et al., 2021]] ). In the rural context, extreme heat contributes to migration out of small communities; for example, see cases reported in Mexico ( [[#Nawrotzki--2015a|Nawrotzki et al., 2015a]] ). Extreme heat events pose a significant risk to residents of small towns across North America due to limited resources to address heat impacts and attendant increased morbidity and mortality ( [[#14.5.6.1|Section 14.5.6.1]] ; [[#McDonald--2016|McDonald et al., 2016]] ; [[#Guo--2018|Guo et al., 2018]] ; [[#D’ulisse--2019|D’ulisse, 2019]] ).

Hot and dry conditions increase risk of wildfires close to human settlements through collateral impacts on properties, economic activity and human health (see Box 14.2; [[#14.5.6.3|Section 14.5.6.3]] ). These environmental conditions also stress natural assets (e.g., urban forests, wetlands, household gardens, green walls) and performance of green infrastructure leading to higher operation and maintenance costs ( ''high confidence'' ) ( [[#Kabisch--2017|Kabisch et al., 2017]] ; [[#Terton--2017|Terton, 2017]] ).

<div id="14.5.5.1.2" class="h4-container"></div>

<span id="storms-and-flooding"></span>
===== 14.5.5.1.2 Storms and flooding =====

<div id="h4-5-siblings" class="h4-siblings"></div>

Short-duration, high-intensity rainfall and other extreme events (e.g., hurricanes, atmospheric river events) create significant flooding risks and impacts for cities in North America and negatively affect the lives, livelihoods, economic activities, infrastructure and access to services ( ''high confidence'' ) ( [[#Amec%20Foster%20Wheeler%20and%20Credit%20Valley%20Conservation--2017|Amec Foster Wheeler and Credit Valley Conservation, 2017]] ; [[#Curry--2019|Curry et al., 2019]] ). In 2016, US flooding events caused 126 fatalities and 11 billion USD (considering the 2016 USD value) in damages ( [[#NOAA--2019|NOAA, 2019]] ). In Canada, flooding accounts for 40% of the costs associated with weather-related disasters recorded since 1970 ( [[#Canadian%20Institute%20for%20Climate%20Choices--2020|Canadian Institute for Climate Choices, 2020]] ); the most costly event was the 2013 Calgary flood (CA-PR) (1.8 billion CAD in catastrophic insurance losses and 6 billion CAD in direct costs such as uninsured losses) ( [[#Office%20of%20the%20Auditor%20General%20of%20Canada--2016|Office of the Auditor General of Canada, 2016]] ). Mexico City is seasonally impacted by high-intensity rainfall events that generate local flooding ( [[#de%20Alba--2014|de Alba and Castillo, 2014]] ). Rural and remote settlements are also threatened by floods; Indigenous lands in Canada are disproportionately exposed to flooding, with almost 22% of residential properties at risk of a 1-in-100-year flood ( [[#Thistlethwaite--2020|Thistlethwaite et al., 2020]] ; [[#Yumagulova--2020|Yumagulova, 2020]] ).

Wind storms and hurricanes are significant climate hazards for North American cities and settlements, affecting urban forests, electricity distribution and service delivery, and damaging buildings and transportation infrastructure (Amec Foster Wheeler Environment and Infrastructure, 2017; [[#British%20Columbia%20Hydro--2019|British Columbia Hydro, 2019]] ; [[#Smith--2020|Smith, 2020]] ), with enduring impacts on small villages due to lost livelihoods and limited recovery capacity (e.g., Rio Lagartos and Las Coloradas in MX-SE after Hurricane Isidore) ( [[#Audefroy--2017|Audefroy and Cabrera Sánchez, 2017]] ). The Pacific coast of Mexico is also experiencing hurricanes such as Patricia (category IV) in 2015 and Newton (category I) in 2016 (CONAGUA, 2015; CONAGUA, 2016); hurricane Patricia affected 56 municipalities in the states of Colima, Nayarit and Jalisco (MX-CE, MX-NW) (Calleja-Reina, 2016).

<div id="14.5.5.1.3" class="h4-container"></div>

<span id="sea-level-rise"></span>
===== 14.5.5.1.3 Sea level rise =====

<div id="h4-6-siblings" class="h4-siblings"></div>

Sea level rise interacts with shoreline erosion, storm surge and wave action, saline intrusion and coastal flooding to directly threaten coastal cities and small communities in North America with impacts to public and private buildings and infrastructure, port and transportation facilities, water resources ( ''high confidence'' ) ( [[#NOAA%20National%20Weather%20Service--2017|NOAA National Weather Service, 2017]] ; [[#Boretti--2019|Boretti, 2019]] ) and cultural heritage sites (see Box 14.4; [[#Dawson--2020|Dawson et al., 2020]] ). Sea level rise is creating conditions where considerable financial investments are needed and, in many cases, are being raised to address adaptation needs (see Box 14.4; CCP6, [[#Fatorić--2017|Fatorić and Seekamp, 2017]] ; [[#Hinkel--2018|Hinkel et al., 2018]] ; [[#Greenan--2018|Greenan et al., 2018]] ). Across North America, high population density and concentrated development along the coast generates exposure to SLR impacts.

<div id="14.5.5.2" class="h3-container"></div>

<span id="projected-impacts-and-risks-1"></span>
==== 14.5.5.2 Projected Impacts and Risks ====

<div id="h3-15-siblings" class="h3-siblings"></div>

Evidence since the AR5 highlights increased risk to quality of life in cities and rural communities as a result of exposure to intensifying climate-change hazards, and the compounding and interacting effects of climate and non-climate factors ( ''medium confidence'' ).

<div id="14.5.5.2.1" class="h4-container"></div>

<span id="rising-temperatures-and-extreme-heat-1"></span>
===== 14.5.5.2.1 Rising temperatures and extreme heat =====

<div id="h4-7-siblings" class="h4-siblings"></div>

Extreme heat events are projected to increase in frequency and intensity across North America in the coming decades ( [[#14.2.2|Section 14.2.2]] ; Figure 14.2F,G). Inland urban areas in the southern and eastern USA are susceptible to urban heat island effects, particularly the Midwest/Great Lakes regions ( [[#Krayenhoff--2018|Krayenhoff et al., 2018]] ) and also Mexico City and many other cities in Mexico ( [[#Vargas--2020|Vargas and Magaña, 2020]] ). Climate change (RCP8.5) interacting with urban form, development and systemic racism ( [[#Schell--2020|Schell et al., 2020]] ; [[#Hsu--2021|Hsu et al., 2021]] ) could worsen risks from extreme heat in North American cities, especially where there is limited adaptation ( ''high confidence'' ) ( [[#Krayenhoff--2018|Krayenhoff et al., 2018]] ). Impacts from extreme heat will be exacerbated when multiple hazards occur simultaneously (e.g., heatwaves concurrent with droughts) ( [[#Mora--2018|Mora et al., 2018]] ; [[#Zscheischler--2018|Zscheischler et al., 2018]] ). Extreme heat events increase energy demand for space cooling in buildings, especially during peak demand periods and heatwaves ( [[#IEA--2018a|IEA, 2018a]] ). This can decrease cooling efficiency, increase emissions of GHG from electricity generation, increase refrigerant loads and associated emissions, and negatively affect air quality ( [[#IEA--2018a|IEA, 2018a]] ). Major electrical grid failure (i.e., blackouts) have increased across the USA and will continue to be particularly dangerous for human health when they coincide with extreme heat events ( [[#Stone--2021|Stone et al., 2021]] ). Efforts to increase resilience of the infrastructure that cities rely on are increasing ( [[#Climate-Safe%20Infrastructure%20Working%20Group--2018|Climate-Safe Infrastructure Working Group, 2018]] ).

Warmer and/or drier conditions may reduce water supply reliability for cities and small communities that rely on surface water sources fed by rain or snowmelt runoff, for example, Victoria and Vancouver, Canada (CA-BC) ( [[#Metro%20Vancouver--2016|Metro Vancouver, 2016]] ; [[#Vadeboncoeur--2016|Vadeboncoeur, 2016]] ; [[#Islam--2017|Islam et al., 2017]] ); San Pedro, Hermosillo and Los Pargas, Aguascalientes, México (MX-NW, MX-CE) ( [[#Vadeboncoeur--2016|Vadeboncoeur, 2016]] ; [[#Soto-Montes-de-Oca--2019|Soto-Montes-de-Oca and Alfie-Cohen, 2019]] ); New York City (US-NE) (NYC Department of Environmental Protection, 2014); and Washington State (US-NW) ( [[#14.5.3.2|Section 14.5.3.2]] ; [[#Fosu--2017|Fosu et al., 2017]] ).

<div id="14.5.5.2.2" class="h4-container"></div>

<span id="storms-and-flooding-1"></span>
===== 14.5.5.2.2 Storms and flooding =====

<div id="h4-8-siblings" class="h4-siblings"></div>

Annual and winter precipitation is expected to increase for most of Canada ( [[#14.2|Section 14.2]] ; Figure 14.2D,E) and will increase flooding in cities and settlements ( ''high confidence'' ) ( [[#Bonsal--2019|Bonsal et al., 2019]] ). Although there is more geographic variation across the continental USA (e.g., between high-latitude and subtropical zones), extreme precipitation events are projected to increase in frequency and intensity with impacts on flood hazards ( [[#14.5.3.2|Section 14.5.3.2]] ; [[#Easterling--2017|Easterling et al., 2017]] ). Winter (snow and ice) storms are expected to increase in northern North America and decrease in southern North America under RCP8.5 ( [[#Jeong--2018b|Jeong and Sushama, 2018b]] ). Projected increases in wind-driven rain exposure is an emerging consideration for moisture-resilient design and management of buildings, especially in western and northern Canada ( [[#Jeong--2020|Jeong and Cannon, 2020]] ).

<div id="14.5.5.2.3" class="h4-container"></div>

<span id="sea-level-rise-1"></span>
===== 14.5.5.2.3 Sea level rise =====

<div id="h4-9-siblings" class="h4-siblings"></div>

In the USA, many people are projected to be at risk of flooding from SLR ( ''high confidence'' ) (see Box 14.4). A projected SLR of 0.9 m by 2100 could place 4.2 million people at risk of inundation in US coastal counties, whereas a 1.8-m SLR exposes 13.1 million people ( [[#Hauer--2016|Hauer et al., 2016]] ). In California, under an extreme 2-m SLR by 2100, 150 billion USD (2010) of property or more than 6% of the state’s GDP and 600,000 people could be affected by flooding ( [[#Barnard--2019|Barnard et al., 2019]] ). A 1-m SLR would inundate 42% of the Albemarle-Pamlico Peninsula in North Carolina and incur property losses of up to 14 billion USD (considering the 2016 USD value) ( [[#Bhattachan--2018|Bhattachan et al., 2018]] ). In nine southeast US states, a 1-m SLR would result in the loss of more than13,000 recorded historical and archaeological sites with over 1000 eligible for inclusion in the National Register for Historic Places ( [[#Anderson--2017|Anderson et al., 2017]] ). This SLR raises groundwater levels by impeding drainage and enhancing runoff during rain events ( [[#Hoover--2017|Hoover et al., 2017]] ); coastal flooding enhances saltwater intrusion affecting drinking water supply in settlements (e.g., coast of Texas) ( [[#Anderson--2016|Anderson and Al-Thani, 2016]] ).

In Canada, SLR is expected to increase the frequency and magnitude of extreme high-water-level events ( [[#Greenan--2018|Greenan et al., 2018]] ) and to create widespread impacts on natural and human systems ( ''high confidence'' ) (see Box 14.4; [[#Lemmen--2016|Lemmen et al., 2016]] ). Although coastal sensitivity is high in the Arctic, Canada’s more populated regions are also sensitive to the impacts of SLR ( [[#Manson--2019|Manson et al., 2019]] ). The Mi’kmaq community of Lennox Island First Nation is exploring relocation options because of erosion from SLR (Savard et al., 2016).

In Mexico, crucial coastal tourism cities, such as Cancun, Isla Mujeres, Playa del Carmen, Puerto Morelos and Cozumel (MX-SE), are at risk of SLR with an estimated economic impact of 1.4–2.3 billion USD ( [[#14.5.7|Section 14.5.7]] ; [[#Ruiz-Ramírez--2019|Ruiz-Ramírez et al., 2019]] ). Negative effects of the ‘coastal squeeze’ phenomena (generated by SLR, land subsidence, sediment deficit and current urbanisation processes) have been documented on tourist destinations along the coasts of the Mexican Gulf of Mexico and Mexican Caribbean. Zoning, limiting urbanisation along the coastline and using NbS (see Box 14.7) are alternatives that could be applied to improve the adaptation of these destinations ( [[#Martínez--2014|Martínez et al., 2014]] ; Salgado and Luisa Martinez, 2017; [[#Lithgow--2019|Lithgow et al., 2019]] ).

Rural low-lying coastal areas are at risk from SLR where natural barriers or shoreline infrastructure are deteriorating and this interacts with remoteness, resource-dependent economies and socioeconomic challenges to adaptive capacity ( [[#Bhattachan--2018|Bhattachan et al., 2018]] ; [[#Manson--2019|Manson et al., 2019]] ). The Northeast Atlantic region of North America (CA-AT, US-NE) is exposed to high risk by combined effects of land subsidence and climate-driven SLR (see Box 14.4; [[#Lemmen--2016|Lemmen et al., 2016]] ; [[#Sweet--2017|Sweet et al., 2017]] ; [[#Fleming--2018|Fleming et al., 2018]] ; [[#Greenan--2018|Greenan et al., 2018]] ).

<div id="14.5.5.3" class="h3-container"></div>

<span id="adaptation-1"></span>
==== 14.5.5.3 Adaptation ====

<div id="h3-16-siblings" class="h3-siblings"></div>

In North American cities, present-day adaptation responses extend beyond the traditional focus on infrastructure to include measures aimed to protect people, property and ecosystems ( ''medium confidence'' ). Barriers to adaptation include challenges related to the local physical and environmental setting, effects of colonialism and racism, socioeconomic attributes of the population, institutional frameworks and competing interests of city stakeholders ( ''medium confidence'' ). The current scale of adaptation is generally not commensurate with reducing risks from projected climatic hazards, although resources exist that provide guidance and examples of effective adaptation ( ''medium confidence'' ). Some remote Canadian communities have demonstrated strengths (e.g., strong social networks) that support resilience to climate change ( [[#Kipp--2020|Kipp et al., 2020]] ; [[#Vodden--2021|Vodden and Cunsolo, 2021]] ). In some US cities with political resistance to action on climate change, adaptation measures focused on addressing extreme events (rather than climate-change impacts) have been able to make progress ( [[#Hamin--2014|Hamin et al., 2014]] ). Enhanced public awareness of the risks from extreme events associated with climate change is important for motivating adaptation ( [[#14.3|Section 14.3]] ; [[#Howe--2019|Howe et al., 2019]] ) and developing a climate-change agenda ( [[#Aragón-Durand--2020|Aragón-Durand, 2020]] ).

Community-level planning tailors adaptation responses and disaster preparedness to the local context but misalignment of policies within and between levels of government can prevent implementation ( [[#Oulahen--2018|Oulahen et al., 2018]] ). Coordination, planning and national support are needed to provide sufficient financial resources to implement climate-resilient policies and infrastructure ( [[#14.7|Section 14.7.3]] ; [[#USGCRP--2018|USGCRP, 2018]] ).

Public health measures to address extreme heat events are more common across North America, with a focus on vulnerable populations (e.g., [[#City%20of%20Toronto--2019|City of Toronto, 2019]] ) and innovative approaches for reaching at-risk populations with an overarching intent of prevention ( ''medium confidence'' ) ( [[#14.4|Section 14.4.6.1]] ; [[#Guilbault--2016|Guilbault et al., 2016]] ). The heatwave plan for Montreal includes visits to vulnerable populations, cooling shelters, monitoring of heat-related illness and extended hours for public pools ( [[#Lesnikowski--2017|Lesnikowski et al., 2017]] ); efforts have reduced heatwave-related mortalities ( [[#Benmarhnia--2016|Benmarhnia et al., 2016]] ).

Other adaptation responses to reduce temperature effects include modifying structures (roofs, engineered materials) and the urban landscape through green infrastructure (e.g., urban trees, wetlands, green roofs), which increases climate resilience and quality of life by reducing urban heat island effects, while additionally improving air quality, capturing stormwater and delivering other co-benefits to the community (e.g., access to food, connection to nature, social connectivity) ( ''high confidence'' ) (see Box 14.7; [[#Ballinas--2016|Ballinas and Barradas, 2016]] ; [[#Emilsson--2017|Emilsson and Sang, 2017]] ; [[#Kabisch--2017|Kabisch et al., 2017]] ; [[#Krayenhoff--2018|Krayenhoff et al., 2018]] ; [[#Petrovic--2019|Petrovic et al., 2019]] ; [[#Schell--2020|Schell et al., 2020]] ). Green infrastructure can be flexible and cost-effective ( [[#Ballinas--2016|Ballinas and Barradas, 2016]] ; [[#Emilsson--2017|Emilsson and Sang, 2017]] ; [[#Kabisch--2017|Kabisch et al., 2017]] ). Initiatives can be ‘bottom-up’ community-led adaptation with support from municipal governments (e.g., East Harlem in New York City) ( [[#Petrovic--2019|Petrovic et al., 2019]] ). Valuing municipal natural assets (e.g., assigning economic value to cooling from urban forests or stormwater retention by urban wetlands) is becoming increasingly common in Canada and the USA ( [[#Wamsler--2015|Wamsler, 2015]] ; [[#Roberts--2017a|Roberts et al., 2017a]] ; [[#Municipal%20Natural%20Assets%20Initiative--2018|Municipal Natural Assets Initiative, 2018]] ). Guidance assists municipalities to identify, value and account for natural assets in their financial planning and asset management programmes ( [[#O’Neil--2017|O’Neil and Cairns, 2017]] ) and consider future climate ( [[#Municipal%20Natural%20Assets%20Initiative--2018|Municipal Natural Assets Initiative, 2018]] ).

Meeting increasing demand for indoor space cooling with equitable access requires new approaches to providing cooling (e.g., equipment efficiencies, refrigerants with lower global warming potential) and electricity production and transmission innovation ( [[#Shah--2015|Shah et al., 2015]] ; [[#IEA--2018a|IEA, 2018a]] ). While energy efficiency and building code standards are not directly established by local governments, they can encourage behaviour change via incentives (e.g., rebates on efficient equipment) or disincentives (e.g., more onerous permit approvals).

Experience with droughts, heatwaves and other weather extremes has led many municipal water managers to accept the importance of building resilience to the risks of future water shortages and costs posed by climate change ( [[#Metro%20Vancouver--2016|Metro Vancouver, 2016]] ; [[#Misra--2021|Misra et al., 2021]] ; [[#WUCA--2021|WUCA, 2021]] ). In the southwest USA, water utilities have introduced demand-management programmes to encourage water conservation (e.g., tiered pricing, incentives for water-efficient appliances and fixtures, and rewards for replacing water-guzzling lawns with water-thrifty native vegetation) ( [[#14.5.3.3|Section 14.5.3.3]] ; [[#Luthy--2020|Luthy et al., 2020]] ; [[#Baker--2021|Baker, 2021]] ). Water providers also have increased their adaptive capacity by diversifying water sources ( [[#Hanak--2015|Hanak et al., 2015]] ).

Adaptation to the risks of wildland–urban interface fire is underway (see Box 14.2; [[#Kovacs--2020|Kovacs et al., 2020]] ), but the scope of adaptation required to sufficiently minimise wildfire risks for cities and settlements across North America has not been assessed ( ''medium confidence'' ). Leadership at the local level is increasingly supported by federal resources that provide guidance on hazard and exposure assessment, property protection, community resilience and emergency planning ( [[#National%20Research%20Council%20of%20Canada--2021|National Research Council of Canada, 2021]] ).

Cities and settlements in North America can be susceptible to multiple flooding hazards (i.e., coastal SLR, pluvial or fluvial flooding); each presents unique adaptation challenges that can be addressed through structural (e.g., armouring coastlines, reservoirs, levees, floodgates; New York City commuter tunnels) and non-structural approaches (e.g., land-use planning and zoning, expanding green infrastructure; Chetumal, Mexico) ( ''high confidence'' ) ( [[#Hardoy--2014|Hardoy et al., 2014]] ). Green infrastructure practices (e.g., open-space preservation, floodplain restoration, urban forestry, de-channelisation of streams) (see Box 14.7) can reduce urban flooding, erosion and harmful runoff ( [[#Kovacs--2014|Kovacs et al., 2014]] ; [[#Angel--2018b|Angel et al., 2018b]] ; Government of Canada, 2021c). Structural approaches have limitations and require trade-offs that could be addressed with a focus on social–ecological solutions and stronger institutional coordination (e.g., flood risk management in Mexico City) ( [[#Aragón-Durand--2020|Aragón-Durand, 2020]] ). In response to high-intensity rainfall events, Mexico City invested in stormwater infrastructure, although additional benefits could have been realised if water supply needs had been incorporated ( [[#de%20Alba--2014|de Alba and Castillo, 2014]] ). Some programmes exist to facilitate stormwater and wastewater infrastructure updating to accommodate increased precipitation across North America. The US federal Clean Water State Revolving Fund provides low-interest loans for states to upgrade infrastructure for climate change, with 42 billion USD provided since 1987 ( [[#ASCE--2019|ASCE, 2019]] ). In Canada, local governments are important leaders in managing engineered and green infrastructure decisions, incentivising property-level flood protection and ensuring service delivery (Government of Canada, 2021c). The civil engineering profession is playing an active role in facilitating an understanding of risks and prioritisation of adaptation investments in communities ( [[#Tye--2021|Tye and Giovannettone, 2021]] ).The high concentration of valuable assets in cities requires mechanisms to facilitate replacement of assets including use of existing and proposed insurance mechanisms ( ''medium confidence'' ) ( [[#14.7|Section 14.7]] ).

Adaptation planning and implementation to address SLR and coastal flooding has been initiated across cities and settlements in North America but varies in preparedness ( ''high confidence'' ) (see Box 14.4). Efforts are supported by SLR design guidelines. In Canada, the Government of British Columbia provided SLR projections for 2050 (i.e., +0.5 m) and 2100 (i.e., +1 m) in order to initiate community vulnerability and risk assessment, and adaptation planning (The Arlington Group Planning + Architecture Inc et al., 2013). Based on recent hurricane impacts in Yucatan, Mexico, recommendations to enhance the rules governing the Mexican Recovery Program included incorporating local knowledge and IK when rebuilding houses and other structures on coasts ( [[#Audefroy--2017|Audefroy and Cabrera Sánchez, 2017]] ). Where in-place adaptation is insufficient, planned retreat is being considered as a sustainable option for reducing future risks ( [[#Saunders-Hastings--2020|Saunders-Hastings et al., 2020]] ).

<div id="box-14.4" class="h2-container box-container"></div>

'''Box 14.4 | Sea Level Rise Risks and Adaptation Responses for Selected North American Cities and Settlements'''
<div id="h2-27-siblings" class="h2-siblings"></div>

Approximately 95 million Americans lived in coastal communities in 2017 ( [[#US%20Census%20Bureau--2019|US Census Bureau, 2019]] ) and in 2013, Canada had roughly 6.5 million coastal residents ( [[#Lemmen--2016|Lemmen et al., 2016]] ), while Mexico had 19 million people living in coastal municipalities in 2015 ( [[#Azuz-Adeath--2018|Azuz-Adeath et al., 2018]] ). Sea level rise around North American coastlines (Figure Box 14.4.1) is projected to be greatest along the coasts of Atlantic Canada, northern Gulf of Mexico for the USA and the Pacific coast of Mexico ( [[#IPCC--2021|IPCC, 2021]] ). Sections 14.5.2.1, 14.5.5.1.3 and 14.5.5.2.3 describe SLR impacts. The status of adaptation to SLR by local governments is variable (see Table Box 14.4.1, where progress is indicated by colour coding) and ranges from financed implementation to preliminary, preparatory or scoping studies and workshops. Adaptation planning and implementation to address SLR and coastal flooding have been initiated across many cities and settlements in North America, but preparedness varies ( ''high confidence'' ).

[[File:35145a94ac79d4af4f96db52d6bc386a IPCC_AR6_WGII_Figure_14_Box_14_4_1.png]]

'''Figure Box 14.4.1 |''' '''Sea level rise projections for 2050, 2100 and 2150 for selected North American cities.''' Projections changes are relative to 2005, which is the central year for the 1994–2014 reference period. Horizontal lines in the boxes represent the median projection, boxes represent 25th to 75th percentile and whiskers the 10th to 90th percentile of SLR projections from all CMIP6 models as well as other lines of evidence (see [[#Fox-Kemper--2021|Fox-Kemper et al., 2021]] Table 9.7 for more details). Two SLR scenarios are provided for lower (SSP126) and higher emissions (SSP585), and are consistent with the WGI AR6 Interactive Atlas ( [[#Gutiérrez--2021b|Gutiérrez et al., 2021b]] . Numbers and colours (see Table Box 14.4.1 for detailed readiness definitions) on the map and in the projections represent the sites and status of SLR adaptation progress. Information supporting SLR adaptation status is summarised in Table Box 14.4.1.

'''Table Box 14.4.1 |''' Status of adaptation actions for locations on the SLR map above according to level of SLR preparedness through adaptation (as discoverable on government websites)

[[File:2122fc076b85d1b07a3a3a144f22f996 IPCC_AR6_WGII_TableBox_14_4_1_1.png]] [[File:2b9ddf2d0d28a36b5f6c61def914e998 IPCC_AR6_WGII_TableBox_14_4_1_2.png]] [[File:3975dbafbe45535b9c5920b9d128432e IPCC_AR6_WGII_TableBox_14_4_1_3.png]] [[File:29bae98c6293af38468ba1dd15dd6f57 IPCC_AR6_WGII_TableBox_14_4_1_4.png]]
Sea Level Rise Adaptation Readiness Levels

* Specific plan, progress on actions - specific plan for SLR with evidence of progress on taking actions including allocating funding for projects
* Specific plan, no evidence of actions taken - specific plan for SLR with concrete actions identified but no evidence of actions taken to date
* Specific plan, no actions specified - specific plan for SLR but does not include specific actions
* General Climate Change plan, mentions sea level rise - general climate-change adaptation action plan, which mentions SLR as a risk, issue or impact but no concrete actions, developed
* No Climate Change plan, but processes underway - No climate-change adaptation action plan but processes underway such as workshops, studies and vulnerability assessments

<div id="14.5.6" class="h2-container"></div>

<span id="health-and-well-being"></span>