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

===== 14.5.5.2.3 Sea level rise =====

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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]] ).

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