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

==== 14.5.8.1 Observed Impacts and Projected Risks of Climate Change ====

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===== 14.5.8.1.1 Agriculture, fisheries and forestry =====

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The wide range of observed and projected impacts of climate hazards on food and fibre in North America are documented in [[#14.5.4|Section 14.5.4]] (also see Chapter 5). Agriculture (US-NW: corn and soybeans), fisheries (cod and pollock) and forestry (Boreal Forest timber yield) are expected to experience substantial and widespread risks by 2°C of global warming above pre-industrial levels ( ''medium'' to ''high confidence'' ) (Figure 14.10). Economic models generally show economic losses in the agricultural sector across North America, especially at higher GWL ( [[#14.5.4|Section 14.5.4]] ; [[#EPA--2017|EPA, 2017]] ; [[#Boyd--2021|Boyd and Markandya, 2021]] ), although the effects in local economies, especially rural areas of the USA that are highly dependent on agriculture, will be substantial even at lower GWLs ( [[#Gowda--2018|Gowda et al., 2018]] ). Full evaluations of climate risks for forestry and fisheries are presented in Sections 14.5.1 and 14.5.4 (also see [[#14.6|Section 14.6]] ), respectively.

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===== 14.5.8.1.2 Transportation =====

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Transportation infrastructure, including roads, bridges, rail, air, sea and pipelines, are highly vulnerable to rising temperatures, SLR, weather extremes, changing ice conditions, permafrost degradation and flooding ( ''high confidence'' ), resulting in damage, disruption to operations, unsafe conditions and supply chain impacts (see Box 14.5; [[#Board--2008|Board and Council, 2008]] ; Natural Resources Conservation Service; [[#Andrey--2017|Andrey and Palko, 2017]] ; [[#Jacobs--2018|Jacobs et al., 2018]] ; [[#Lemmen--2021|Lemmen et al., 2021]] ). In the Mexican states of Veracruz, Tabasco, San Luis Potosí, Chiapas and Oaxaca, 105,000 infrastructure sites, mostly major connecting roads, were found to be at risk of flooding from tropical storms (De la Peña et al. 2018). Low water levels in the Great Lakes has severely impacted US grain transport ( [[#Attavanich--2013|Attavanich et al., 2013]] ). High-intensity rain events destroyed 1000 km of roads and washed out hundreds of bridges and culverts in 2013 resulting in an estimated 6 billion CAD (considering the 2013 CAD value) in damages and recovery costs in Alberta, Canada ( [[#Palko--2017|Palko and Lemmen, 2017]] ). In 2019, the rail line from Winnipeg to Churchill Manitoba, which is the only ground transportation to the community and to Canada’s only deep-water Arctic port, was reopened after being closed for over 2 years due to the cumulative effects of flooding, permafrost degradation and political challenges ( [[#Lin--2020|Lin et al., 2020]] ). In the USA, the number of heat-related train delays has increased ( [[#Bruzek--2013|Bruzek et al., 2013]] ; [[#Chinowsky--2019|Chinowsky et al., 2019]] ) and, by the end of the century, may cause economic losses of 25–45 billion USD (RCP4.5) or 35–60 billion USD (RCP8.5) ( [[#Chinowsky--2019|Chinowsky et al., 2019]] ). Sea ice reduction in the North American Arctic has led to a rapid increase in ship traffic ( [[#Huntington--2015|Huntington et al., 2015]] ; [[#Phillips--2016|Phillips, 2016]] ; [[#Pizzolato--2016|Pizzolato et al., 2016]] ; [[#Huntington--2021b|Huntington et al., 2021b]] ; [[#Li--2021|Li et al., 2021]] ) with cascading risks related to invasive species introduction, accident rates, black carbon emissions, underwater noise pollution for marine mammals and risks to subsistence harvesting activities in Indigenous communities ( [[#Ware--2014|Ware et al., 2014]] ; [[#Council%20of%20Canadian%20Academies--2016|Council of Canadian Academies, 2016]] ; Huntington, 2021; [[#Verna--2016|Verna et al., 2016]] ; [[#Chan--2019|Chan et al., 2019]] ).

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===== 14.5.8.1.3 Energy, oil and gas, and mining =====

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Climate change is increasing the demand for electric power for cooling and threatens existing power supply ( ''high confidence'' ) ( [[#14.5.5|Section 14.5.5]] ). Increased energy demand often occurs during peak energy usage and especially during heatwaves ( [[#Cruz--2013|Cruz and Krausmann, 2013]] ; [[#Leong--2015|Leong and Donner, 2015]] ). Cooling represented 74% of peak electricity demand in Philadelphia on a particularly hot day in July 2011 ( [[#Waite--2017|Waite et al., 2017]] ; [[#IEA--2018b|IEA, 2018b]] ). In Canada, warming temperatures are expected to reduce demand for heating by 18–33% and increase demand for cooling by 14–126% by 2070 compared with 1959–1989 and 1998–2014 baseline periods, respectively ( [[#Berardi--2020|Berardi and Jafarpur, 2020]] ). The effects on hydropower are uneven across the region with the potential for increases in capacity in Canada but declines of over 20% in Mexico (RCP4.5 and RCP8.5) ( [[#Turner--2017|Turner et al., 2017]] ). Electricity demand in the USA is projected to increase by 5.3% per degree Celsius rise in temperature ( [[#Hsiang--2017|Hsiang et al., 2017]] ). Energy infrastructure, such as drilling platforms, refineries and pipelines, and evacuation routes, are also increasingly vulnerable to higher sea levels, hurricanes, storm surges, mobile multi-year sea ice, erosion, inland flooding, wildfires and other climate-related changes ( [[#Zamuda--2018|Zamuda et al., 2018]] ).

Operational efficiency and human safety at mining and energy production sites is expected to be adversely affected by increases in extreme events ( [[#14.2|Section 14.2]] ), including storms, heavy rains, riverine flooding and wildfires ( ''high confidence'' ). General remoteness of many mining sites (especially in the North American Arctic) exacerbates risks related to emergency responses to extreme events such as wildfire ( ''medium confidence'' ). The 2016 Fort McMurray wildfire in Alberta, Canada, forced the evacuation of 88,000 people and the shutdown of mine operations. Damages were minimal because companies had undertaken proactive FireSmart interventions specifically developed for the industry (see Box 14.1; [[#Council%20of%20Canadian%20Academies--2019|Council of Canadian Academies, 2019]] ). Onshore oil field production in Tabasco, Mexico, which accounts for 16% of the country’s daily output, was interrupted by extensive flooding ( [[#Cruz--2013|Cruz and Krausmann, 2013]] ). Two-thirds of mine operators globally, including major operators in North America, have experienced production challenges related to water shortages and flooding ( [[#Carbon%20Disclosure%20Project--2013|Carbon Disclosure Project, 2013]] ). Water availability stress due to climate change is lower in Canada than in the USA and Mexico, and mines in Canada may be less exposed to this risk ( [[#World%20Resourcs%20Institute--2012|World Resourcs Institute, 2012]] ) with some exceptions, that is, water-intensive oil sands mining in the Athabasca River basin in Canada ( [[#14.5.3|Section 14.5.3]] ; [[#Leong--2016|Leong and Donner, 2016]] ).Warming temperatures also have the potential to alter the nature, characteristics and quality of mineral resources such as kaolin or limestone ( [[#Phillips--2016|Phillips, 2016]] ).

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===== 14.5.8.1.4 Construction =====

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In the USA, construction workers comprise 6% of the total workforce but accounted for 36% of all occupational heat-related deaths from 1992 to 2016 ( [[#Dong--2019|Dong et al., 2019]] ). It is expected that total labour hours among outdoor construction workers will decrease by 0.53% (±0.01%) per degree Celsius based on existing warming trends ( [[#Hsiang--2017|Hsiang et al., 2017]] ; also see [[#EPA--2017|EPA, 2017]] ). Risks are expected to be exacerbated as SLR and storm surge expands the risk zone for coastal flooding exposing more property to inundation and enhancing construction demand (see Box 14.4; [[#14.5.5.1.3|Section 14.5.5.1.3]] ; [[#EPA--2017|EPA, 2017]] ). Meeting existing and projected demand for water in affected regions could also require building new desalination plants. For example, Texas has constructed over 44 desalination plants across the state because of a lack of freshwater to meet potable water demand and due to climate-driven droughts ( [[#Kloesel--2018b|Kloesel et al., 2018b]] ). Other infrastructure damaged by floods and SLR will need to be reassessed and perhaps relocated away from the coast. Relocation requires availability of land that frequently does not exist within urban areas (Lithogow, 2019). Some US tribes and Indigenous groups in Canada lack the financial resources to build climate-resilient infrastructure, such as housing and sewage treatment facilities, to assure clean drinking water ( [[#Martínez--2014|Martínez et al., 2014]] ; Salgado and Luisa Martinez, 2017; [[#Lithgow--2019|Lithgow et al., 2019]] ).

Permafrost thaw in northern North America will result in increased construction and reconstruction needs ( ''medium confidence'' ) related to direct damage to buildings, roads, airport runways and other critical infrastructure including decreased bearing capacities of building and pipeline foundations, damage to road surfaces, and deterioration of reservoirs and impoundments used for wastewater and mine tailings containment ( [[#Pendakur--2017|Pendakur, 2017]] ; [[#Meredith--2019|Meredith et al., 2019]] ). Ice roads have become less safe due to warming, pavement damage has increased related to seasonal thaw–freeze cycles and there have been interruptions in airport operations, water and sewage service, and school operations in the Canadian territories of Yukon and Nunavut (Canadian Western and Eastern Arctic, i.e., CA-WA and CA-EA in Figure 14.1) ( [[#Council%20of%20Canadian%20Academies--2019|Council of Canadian Academies, 2019]] ). By the end of the century, the economic impact of projected reconstruction of Alaska’s public infrastructure due to climate change (mainly from permafrost thaw) is estimated to range from 4.2 billion USD (RCP4.5) to 5.5 billion USD (RCP8.5) ( [[#Melvin--2017|Melvin et al., 2017]] ; [[#Markon--2018|Markon et al., 2018]] ).

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===== 14.5.8.1.5 Manufacturing =====

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Twelve million Americans (Bureau of Labor Statistics, 2015), 1.5 million Canadians (Statistics Canada, 2020) and 9 million Mexicans (Statistics Mexico, 2021) are employed in manufacturing. The southeast USA and Texas have the highest manufacturing output, with 34% of total US output (700 billion USD yr –1 ). The impact of climate change on manufacturing varies greatly by region. Vulnerability of the sector to climate change stems from exposure of workers to increasing temperatures and humidity, exposure of facilities to SLR and flooding, and changes in water supply and quality required in many manufacturing processes ( [[#Lall--2018|Lall et al., 2018]] ).

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===== 14.5.8.1.6 Labour Productivity =====

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Climate change is negatively affecting working conditions and labour productivity in North America ( ''medium confidence'' ) ( [[#14.5.6.1|Section 14.5.6.1]] ; see Box 14.5) ''.'' Working conditions in temperatures above a heat index of 85°F (29.4°C) are correlated with potentially hazardous health conditions ( [[#Tustin--2018|Tustin et al., 2018]] ), and for every degree Celsius increase in temperature, labour productivity is estimated to be reduced by 0.11% for low-risk workers and 0.53% for high-risk workers (i.e., construction, mining, agriculture and manufacturing) ( [[#Hsiang--2017|Hsiang et al., 2017]] ). By mid-century (RCP8.5), temperature increase, changing water availability and SLR are projected to result in a 0.6% drop in labour productivity in auto, timber, textile and chemical manufacturing in the southeast and Texas regions ( [[#Kinniburgh--2015|Kinniburgh et al., 2015]] ; [[#Hsiang--2017|Hsiang et al., 2017]] ). Labour productivity in the US automobile industry decreases by 8% for every six or more days of consecutive unusually hot weather (above 90°F/32.2°C) ( [[#Cachon--2012|Cachon et al., 2012]] ). Thirty percent of California workers are employed in high-risk industries, such as agriculture, with exposure to high temperature leading to loss in productivity ( [[#Rogers--2015|Rogers et al., 2015]] ). Under RCP8.5 increases in extreme temperatures, labour productivity in the USA is projected to decrease, costing 190 billion USD in lost wages by 2090 ( [[#EPA--2017|EPA, 2017]] ; [[#Kjellstrom--2019|Kjellstrom et al., 2019]] ; also see [[#Gubernot--2014|Gubernot et al., 2014]] ; [[#Kiefer--2016|Kiefer et al., 2016]] ; [[#Carter--2018|Carter et al., 2018]] ).

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