Editing IPCC:AR6/WGII/TS (section)

=== Risks from sea level rise ===

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'''TS.C.5 Coastal risks will increase by at least one order of magnitude over the 21st century due to committed sea level rise impacting ecosystems, people, livelihoods, infrastructure, food security, cultural and natural heritage and climate mitigation at the coast. Concentrated in cities and settlements by the sea, these risks are already being faced and will accelerate beyond 2050 and continue to escalate beyond 2100, even if warming stops. Historically rare extreme sea level events will occur annually by 2100, compounding these risks (''' '''''high confidence''''' ''').''' { 3.4.2, 3.5.5, 3.6.3, 9.9.4, Box 11.6, 13.2, Box 13.1, 14.5.2, Box 14.4, [https://www.ipcc.ch/chapter/ts#CCP2.2 CCP2.2] , CCB SLR }

'''TS.C.5.1 Under all emissions scenarios, coastal wetlands will''' '''''likely''''' '''face high risk from sea level rise in the mid-term (''' '''''medium confidence''''' '''), with substantial losses before 2100. These risks will be compounded where coastal development prevents upshore migration of habitats or where terrestrial sediment inputs are limited and tidal ranges are small (''' '''''high confidence''''' ''').''' Loss of these habitats disrupts associated ecosystem services, including wave-energy attenuation, habitat provision for biodiversity, climate mitigation and food and fuel resources ( ''high confidence'' ). Near- to mid-term sea level rise will also exacerbate coastal erosion and submersion and the salinisation of coastal groundwater, expanding the loss of many different coastal habitats, ecosystems and ecosystem services ( ''medium confidence'' ). { 3.4.2, 3.5.2, 3.5.5, 3.6.3, 9.6.2, 11.3.1, 13.4.1, 13.4.2, 14.5.2, CCB NATURAL, CCB SLR }

'''TS.C.5.2 The exposure of many coastal populations and associated development to sea level rise is high, increasing risks, and is concentrated in and around coastal cities and settlements (''' '''''virtually certain''''' ''').''' High population growth and urbanisation in low-lying coastal zones will be the major driver of increasing exposure to sea level rise in the coming decades ( ''high confidence'' ). By 2030, 108–116 million people will be exposed to sea level rise in Africa (compared to 54 million in 2000), increasing to 190–245 million by 2060 ( ''medium confidence'' ). By 2050, more than a billion people located in low-lying cities and settlements will be at risk from coast-specific climate hazards, influenced by coastal geomorphology, geographical location and adaptation action ( ''high confidence'' ). { 9.9.1, 9.9.4, Box 11.6, 14.5.2, Box 14.4, [https://www.ipcc.ch/chapter/ts#CCP2.2 CCP2.2] , CCB SLR }

'''TS.C.5.3 Under all climate and socioeconomic scenarios, low-lying cities and settlements, small islands, Arctic communities, remote Indigenous communities and deltaic communities will face severe disruption by 2100, and as early as 2050 in many cases (''' '''''very high confidence''''' ''').''' Large numbers of people are at risk in Asia, Africa and Europe, while a large relative increase in risk occurs in small island states and in parts of North and South America and Australasia. Risks to water security will occur as early as 2030 or earlier for the small island states and Torres Strait Islands in Australia and remote Maori communities in New Zealand. By 2100, compound and cascading risks will result in the submergence of some low-lying island states and damage to coastal heritage, livelihoods and infrastructure ( ''very high confidence'' ). Sea level rise, combined with altered rainfall patterns, will increase coastal inundation and water-use allocation issues between water-dependent sectors, such as agriculture, direct human consumption, sanitation and hydropower ( ''medium confidence'' ). { Box 4.2, 5.13, 9.12, 9.9.1, 9.9.4, 11.4.1, 11.4.2, Box 11.6, 14.5.2, Box 14.4, [https://www.ipcc.ch/chapter/ts#CCP2.2 CCP2.2] , CCB SLR }

'''TS.C.5.4 Risks to coastal cities and settlements are projected to increase by at least one order of magnitude by 2100 without significant adaptation and mitigation action (''' '''''high confidence''''' ''').''' The population at risk in coastal cities and settlements from a 100-year coastal flood increases by approx. 20% if the global mean sea level rises by 0.15 m relative to current levels, doubles at 0.75 m and triples at 1.4 m, assuming present-day population and protection height ( ''high confidence'' ). For example, in Europe, coastal flood damage is projected to increase at least 10-fold by the end of the 21st century, and even more or earlier with current adaptation and mitigation ( ''high confidence'' ). By 2100, 158–510 million people and USD7,919–12,739 billion in assets are projected to be exposed to the 1-in-100-year coastal floodplain under RCP4.5, and 176–880 million people and USD8,813–14,178 billion assets under RCP8.5 ( ''high confidence'' ). Projected impacts reach far beyond coastal cities and settlements, with damage to ports potentially severely compromising global supply chains and maritime trade, with local to global geopolitical and economic ramifications ( ''medium confidence'' ). Compounded and cascading climate risks, such as tropical cyclone storm surge damage to coastal infrastructure and supply chain networks, are expected to increase ( ''medium confidence'' ). (Figure TS.9 URBAN) { 3.5.5, 3.6.2, 6.2.5, 6.2.7, 9.9.4, 9.12.2, 11.4, Box 11.4, Box 11.6, Table 11.14, 13.2.1, 13.2.2, 13.6.2, 13.10.2, Box 13.1, 14.5.5, Box 14.4, Box 14.5, [https://www.ipcc.ch/chapter/ts#CCP2.2 CCP2.2.1] , [https://www.ipcc.ch/chapter/ts#CCP2.2 CCP2.2.2] , [https://www.ipcc.ch/chapter/ts#CCP6.2.3 CCP6.2.3] , [https://www.ipcc.ch/chapter/ts#CCP6.2 CCP6.2.7] , [https://www.ipcc.ch/chapter/ts#CCP6.2 CCP6.2.8] , BoxCCP6.1, CCB SLR }

'''TS.C.5.5 Particularly exposed and vulnerable coastal communities, especially those relying on coastal ecosystems for protection or livelihoods, may face adaptation limits well before the end of this century, even at low warming levels (''' '''''high confidence''''' ''').''' Changes in wave climate superimposed on sea level rise will significantly increase coastal flooding ( ''high confidence'' ) and erosion of low-lying coastal and reef islands ( ''limited evidence, medium agreement'' ). The frequency, extent and duration of coastal flooding will significantly increase from 2050 ( ''high confidence'' ), unless coastal and marine ecosystems are able to naturally adapt to sea level rise through vertical growth and landward migration ( ''low confidence'' ). Permafrost thaw, sea level rise, and reduced sea ice protection is projected to damage or cause loss to many cultural heritage sites, settlements and livelihoods across the Arctic ( ''very high confidence'' ). Deltaic cities and settlements characterised by high inequality and informal settlements are especially vulnerable ( ''high confidence'' ). Although risks are distributed across cities and settlements at all levels of economic development, wealthier and more urbanised coastal cities and settlements are more likely to be able to limit impacts and risk in the near- to mid-term through infrastructure resilience and coastal protection interventions, with highly uncertain prospects in many of these locations beyond 2100 ( ''high confidence'' ). Prospects for enabling and contributing to climate resilient development thus vary markedly within and between coastal cities and settlements ( ''high confidence'' ). { 9.9.4, 11.3.5, Table Box 11.6.1, 12.3, 12.4, Figure 12.7, Figure 12.9, Table 12.1, Table SM12.5, 13.2, 15.3.3, [https://www.ipcc.ch/chapter/ts#CCP2.2 CCP2.2.1] , [https://www.ipcc.ch/chapter/ts#CCP2.2 CCP2.2.3] , [https://www.ipcc.ch/chapter/ts#CCP2.2 CCP2.2.5] , Table SMCCP2.1 }

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