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

==== 14.5.5.1 Observed Impacts ====

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===== 14.5.5.1.1 Rising temperatures and extreme heat =====

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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]] ).

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===== 14.5.5.1.2 Storms and flooding =====

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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).

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===== 14.5.5.1.3 Sea level rise =====

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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.

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