Editing IPCC:AR6/SROCC/Chapter-5 (section)

==== 5.5.2.2 Human Systems ====

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Many of the world’s great cities lie within the coastal region, and climate change impacts put these cities, their inhabitants and their economic activities at risk. Section 5.5.2.2 assesses the impacts of climate change, adaptation response and benefits upon human systems, including coastal communities, built infrastructure, fisheries and aquaculture, coastal tourism, government and health systems. Table 5.8 provides a summary of the assessment, with citations provided in the Supplementary Material Table 5.7.

Poorly planned (Ataur Rahman and Rahman, 2015), located (Abedin et al., 2014; Betzold and Mohamed, 2017; Linkon, 2018) and managed urban settlements or human systems, driven by growing human coastal populations (Perkins et al., 2015; Moosavi, 2017; Carter, 2018) and compounded by the disruption of coastal and catchment physical processes (Nagy et al., 2014; Broto et al., 2015; Marfai et al., 2015; Kabisch et al., 2017) and pollution (Zikra et al., 2015; Peng et al., 2017) are major human drivers of change compounding the impacts of climate change.

Coastal communities, built infrastructure and fisheries and aquaculture (Table 5.8) are likely to be significantly affected through the disruption of coastal physical processes (DasGupta and Shaw, 2015; Betzold and Mohamed, 2017; Hagedoorn et al., 2019) leading to coastal erosion, flooding, salt water intrusion and built infrastructure damage (Dhar and Khirfan, 2016; Hobday et al., 2016a; Jurjonas and Seekamp, 2018) ( ''robust evidence, high agreement'' ). Ecosystem degradation and biodiversity loss will further compound impacts in coastal communities and fisheries and aquaculture (Ataur Rahman and Rahman, 2015; Petzold and Ratter, 2015; Dhar and Khirfan, 2016), with sub-lethal species impacts like changes in the productivity and distribution of fisheries target species reported for the latter (Gourlie et al., 2018; Nursey-Bray et al., 2018; Pinsky et al., 2018) ( ''high confidence'' ). This is likely to result in decreased access to ecosystem services (Asch et al., 2018; Cheung et al., 2018b; Finkbeiner et al., 2018) ( ''medium evidence, high agreement'' ), local declines in agriculture and fisheries (Cvitanovic et al., 2016; Faraco et al., 2016) ( ''high confidence'' ) and livelihood impacts (Harkes et al., 2015; Busch et al., 2016; Valmonte-Santos et al., 2016) ( ''high confidence'' ) in coastal communities and fisheries and aquaculture, particularly increased food insecurity and health risk in the latter ( ''high confidence'' ). These livelihood impacts are likely to increase social vulnerability ( ''high confidence'' ). Businesses within coastal communities are likely to experience disruptions and losses ( ''robust evidence, high agreement'' ).

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===== 5.5.2.2.1 Coastal communities =====

This section describes a range of adaptation responses reported at the level of the individual or community. Hard engineering responses included small scale hard infrastructure coastal defenses (Betzold and Mohamed, 2017; Jamero et al., 2018), design responses at the household level (Ataur Rahman and Rahman, 2015; Linkon, 2018) and retreat (Marfai et al., 2015). Ecosystem restoration and protection, particularly in mangroves (Ataur Rahman and Rahman, 2015; Bennett et al., 2016; Jamero et al., 2018; Hagedoorn et al., 2019) through community participation programmes (Barbier, 2015; Petzold and Ratter, 2015; Bennett et al., 2016; Dhar and Khirfan, 2016; Jamero et al., 2018) was strongly supported in the literature as a means to improve access to or storage of natural resources ( ''medium evidence, high agreement'' ).

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'''Table 5.8'''
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Summary of reported Adaptation responses (A), the Impacts (I) they aimed to address, and the expected Benefits (B) in human systems within Physical, Ecological, Social, Governance, Economic and Knowledge categories. Legend: a + sign indicates ''robust evidence'' , a triangle indicates ''medium evidence'' and an underline indicates ''limited evidence'' . Dark blue cells indicate ''high agreement'' , blue indicates ''medium agreement'' and light blue indicates either ''low agreement'' (denoted by presence of a sign) if sufficient papers were reviewed for an assessment or no assessment (if less than three papers were assessed per cell). Papers used for this assessment can be found in SM5.6.

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Social responses include increasing climate change awareness, improving participatory decision making through bottom-up approaches, community organisation for action and engagements with local management authorities (Dutra et al., 2015; Tapsuwan and Rongrongmuang, 2015; Galappaththi et al., 2017; Ray et al., 2017; Cinner et al., 2018; Hagedoorn et al., 2019). In coastal communities, and indeed in most other sectors, despite consensus on the importance of cooperation in tackling climate change (Elrick-Barr et al., 2016), adaptation progress may be hampered by competing economic interests and worldviews (Hamilton and Safford, 2015), which can be compounded by limited climate change knowledge (Nanlohy et al., 2015). Factors like home ownership and a general future planning ability support resilience (Elrick-Barr et al., 2016). Climate change adaptation capacity is shaped by historical path dependencies, local context and international linkages, while action is shaped by science, research partnerships and citizen participation (Hernández-Delgado, 2015; Sheller and León, 2016). Locally context-specific data to guide appropriate adaptation response remains a knowledge gap (Abedin and Shaw, 2015; Hobday et al., 2015; Lirman and Schopmeyer, 2016; Williams et al., 2016)

Coastal and oceanic adaptation responses are greatly complicated by the presence of competing interests (either between user groups, communities or nations), where considerations other than climate change need to be incorporated into cooperation agreements and policy (Wong et al., 2014a). The deployment of either built or natural protection systems, or adopting a ‘wait and see’ approach, is subject to the social acceptance of these approaches in communities (Poumadère et al., 2015; Sherren et al., 2016; Torabi et al., 2018). Similarly, the willingness to move away from climate change impacted zones is dependent upon a range of other socioeconomic factors like age, access to resources and crime (Bukvic et al.; Rulleau and Rey-Valette, 2017). Adaptation to climate change includes a range of non-climatic and social variables that complicate implementation of adaptation plans ( ''robust evidence, high agreement'' ).

Improving community participation and integrating knowledge systems (local, traditional and scientific) supports coastal community adaptation responses ( ''high confidence'' ), providing improved co-production of knowledge ( ''medium evidence, high agreement'' ), improved community awareness ( ''medium evidence, medium agreement'' ) and better-informed, more cohesive coastal communities ( ''limited evidence, medium agreement'' ).

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===== 5.5.2.2.2 Built infrastructure =====

Built infrastructure impacts are most frequently addressed through hard engineering approaches including: construction of groins, seawalls, revetments, gabions and breakwaters (Friedrich and Kretzinger, 2012; Vikolainen et al., 2017); improving drainage and raising the height of roadways and other fixed-location infrastructure (Perkins et al., 2015; Becker et al., 2016; Colin et al., 2016; Asadabadi and Miller-Hooks, 2017; Brown et al., 2018a); erosion control systems (Jeong et al., 2014); and the relocation of infrastructure (Friedrich and Kretzinger, 2012; Colin et al., 2016). Nature-based responses are increasingly being reported as complementary and supporting tools (van der Nat et al., 2016; Kabisch et al., 2017; Gracia et al., 2018) using ecological engineering (Perkins et al., 2015; van der Nat et al., 2016; Moosavi, 2017) combined with innovative construction strategies (Moosavi, 2017).

When implemented together, hard and soft engineering responses provide social (Gracia et al., 2018, Martínez et al., 2018; Woodruff, 2018) and ecological (Perkins et al., 2015; van der Nat et al., 2016; Gracia et al., 2018) co-benefits with reduced damage costs (Jeong et al., 2014). Constraints on implementation include the space and extra cost required by ecological infrastructure, sub-optimal performance when impacted by natural physical processes that are disrupted (Gracia et al., 2018) or restrictions associated with governance (Vikolainen et al., 2017). Adaptation planning including local communities can improve implementation and help fill knowledge gaps (Kaja and Mellic, 2017; Moosavi, 2017; Martínez et al., 2018; Mikellidou et al., 2018). Benefits include increased resilience in coastal infrastructure and better informed decision making tools ( ''medium confidence'' ),

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<span id="adaptation-in-fisheries-and-aquaculture"></span>
===== 5.5.2.2.3 Adaptation in fisheries and aquaculture =====

Sixty percent of assessed species are projected to be at high risk from both overfishing and climate change by 2050 (RCP8.5), particularly tropical and subtropical species (Cheung et al., 2018b). Overfishing is one of the most important non-climatic drivers affecting the sustainability of fisheries (Islam et al., 2013; Heenan et al., 2015; Faraco et al., 2016; Dasgupta et al., 2017; Cheung et al., 2018b; Harvey et al., 2018). Pursuing sustainable fisheries practices under a low emissions scenario would decrease risk by 63%. This highlights the importance of effective fisheries management (Gaines et al., 2018). Eliminating overfishing would, however, require reducing current levels of fishing effort, with a potential short-term reduction in catches impacting livelihoods and the food security of coastal communities (Hobday et al., 2015; Dey et al., 2016; Rosegrant et al., 2016; Campbell, 2017; Finkbeiner et al., 2018). Despite consensus on the effectiveness of eliminating overfishing in supporting climate change adaptation in fisheries ( ''robust evidence, high agreement)'' , successful adaptation outcomes remain aspirational.

Range shifts under ocean warming (Section 5.2.3) will alter the distribution of fish stocks across political boundaries, thus demand for transboundary fisheries management will increase. Redistribution of transboundary fish stocks between countries (Ho et al., 2016; Gourlie et al., 2017; Asch et al., 2018) could destabilise existing international fisheries agreements and increase the risk of international conflicts (Section 5.4.2). Adaptation to reduce risks in international fisheries management could involve improving planning for cooperative management between countries informed by reliable predictions (Payne et al., 2017) and projections (Pinsky et al., 2018) of species shifts and associated uncertainties. Cooperative international fisheries arrangements, such as flexible fishing effort allocation and adaptive frameworks (Colburn et al., 2016; Cvitanovic et al., 2016; Faraco et al., 2016) may also improve the robustness of fisheries management (Miller et al., 2013). Thus, although range shifts pose significant challenges to transboundary fisheries management, proactive planning and adjustment of fisheries management arrangements, informed by scientific projections, could help improve adaptive capacity ( ''medium confidence'' ). The effectiveness of incorporating MPAs as an adaptation strategy to climate change can be improved by considering climate impacts in the design of MPAs ( ''medium, high agreement'' ).

Improving integrated coastal management and better planning for MPAs by incorporating projected shifting biological communities, abundance and life history changes (Álvarez-Romero et al., 2018) due to climate change could contribute towards improved fisheries adaptive management by, for example, increasing resilience of habitats, providing refugia for species with shifting distributions and by conserving biodiversity (Faraco et al., 2016; Valmonte-Santos et al., 2016; Dasgupta et al., 2017; Le Cornu et al., 2017; Roberts et al., 2017; Asch et al., 2018; Cheung et al., 2018b; Harvey et al., 2018; Jones et al., 2018; O’Leary and Roberts, 2018) (Sections 5.2.3, 5.3, 5.4.1), but MPAs may also reduce access to subsistence fishers, increasing their vulnerability to food insecurity (Bennett et al., 2016; Faraco et al., 2016). The global area of MPAs is rapidly increasing towards the United Nations’ target of 10% of the global ocean. While this is encouraging, it is estimated that only 2% of the ocean is well enough managed, as described in (Edgar et al., 2014), to meet conservation goals (Sala et al., 2018). Improving the implementation and coordination of policies, and improving integrated coastal management and MPAs have emerged in the literature as important adaptation governance responses ( ''robust evidence, medium agreement'' ).

Governance responses to support adaptation in fisheries communities include conducting vulnerability assessments, improving monitoring of ecosystem indicators and evaluating management strategies (Himes-Cornell and Kasperski, 2015b; Busch et al., 2016). Socioeconomic factors like access to alternative income, mobility, gender and religion collectively shape a community’s adaptation response (Arroyo Mina et al., 2016). In West Africa, the industrial fishery response to climate change induced reductions in landings was the expansion of fishing grounds, which increased operational costs (Belhabib et al., 2016). This response is not available to artisanal and local fishing communities, who are considered highly vulnerable (Kais and Islam, 2017). Access to finance to support these communities or their governments could help them reach novel fishing grounds, and, therefore, potentially reduce their vulnerability. Food security linked to fisheries depends on stock recovery, but also on access to and distribution of the harvest, as well as gender considerations (Béné et al., 2015). Hence, granting preferential access to dependent coastal communities should be considered in examining policy options. Other adaptation responses include improved fishing gear and technology, use of fish aggregating devices and uptake of insurance products (Zougmoré et al., 2016) [see Barange et al. (2018) for a summary of possible adaptation responses]. Community response as a part of climate change adaptation for local fisheries is an important element in assessing adaptive capacity ( ''medium evidence, good agreement'' ),

Fisheries management strategies depend heavily upon data collection and monitoring systems. These include the accuracy of data collected in respect of predicting environmental conditions, over time scales from months to decades (Dunstan et al., 2018), effective monitoring and evaluative mechanisms (Le Cornu et al., 2017; Gourlie et al., 2018), controlling for aspects of fish population dynamics like recruitment success and fish movement (Mace, 2001). Seasonal to decadal  [https://www.sciencedirect.com/topics/earth-and-planetary-sciences/climate-prediction climate prediction]  systems allow for skillful predictions of climate variables relevant to fisheries management strategies (Hobday et al., 2016b; Payne et al., 2017). Effective fisheries adaptation responses will require knowledge development including better monitoring, modelling and improving decision support frameworks ( ''medium evidence, high agreement'' ) and improving forecasting and early warning systems ( ''medium evidence, medium agreement'' ).

In considering a participatory decision making approach for fisheries management that responds to climate change, Heenan et al. (2015){Heenan,  #274;Heenan, 2015 #274} provided a number of key elements that contribute towards a successful outcome. These include expert knowledge of climate change threats to fish habitats, stocks and landings, the necessity of transdisciplinary collaboration and stakeholder participation, broadening the range and scope of fisheries systems and increased commitment of resources and capacity. This was considered in the context of the ability of developing countries to sustainably exploit fisheries resources and related ecosystems. More research is required on socioecological responses to climate change impacts on fishery communities, including such aspect as like risk reduction, adaptive capacity through knowledge attainment and social networks, developing alternative skills and participatory approaches to decision making (Dubey et al., 2017; Shaffril et al., 2017; Finkbeiner et al., 2018). Important fisheries adaptation responses in relation to knowledge management include improving participatory processes ( ''robust evidence, high agreement'' ), integrating knowledge systems ( ''medium evidence, high agreement'' ), and stakeholder identification, outreach and education ( ''medium evidence, medium agreement'' ). Ecosystem-based adaptation, community participatory programmes, and improving agricultural and fisheries practices are very strongly supported in the literature ( ''high confidence'' ).

Less still is known about how climate change will affect the deep oceans and its fisheries (Section 5.2.3 and 5.2.4), the vulnerability of its habitats to fishing disturbance and future effects on resources not currently harvested (FAO, 2019). Johnson et al. (2019) concluded that in a 20- to 50-year timeframe, the effectiveness of virtually all north Atlantic deep water and open ocean area-based management tools can be expected to be affected. They concluded that more precise and detailed oceanographic data are needed to determine possible refugia, and more research on adaptation and resilience in the deep sea is needed to predict ecosystem response times.

As with fisheries, community- and ecosystem-based adaptation responses, an integrated coastal management framework is considered useful for planning for anticipated challenges for aquaculture (Ahmed and Diana, 2015b; Barange et al. 2018). Where ''in situ'' adaptation is not possible, translocation and polyculture (Ahmed and Diana, 2015a; Bunting et al., 2017) have been suggested as appropriate responses, but this would suit commercial rather than subsistence interests. Policy, economic, knowledge and other types of support are required to build socioecological resilience of vulnerable coastal aquaculture communities (Harkes et al., 2015; Bunting et al., 2017; Rodríguez-Rodríguez and Bande Ramudo, 2017), which requires a deep understanding of the nature of stressors and a commitment for collective action (Galappaththi et al., 2017). Climate resilient pathway development (see Cross-Chapter Box 2) is considered a useful framework for Sri Lankan shrimp aquaculture (Harkes et al., 2015). Another example of successful aquaculture adaptation is the employment of near real time monitoring technology to track the carbonate chemistry in water to reduce bio-erosion in shellfish from acidification (Barton et al., 2015; Cooley et al., 2016). Numerous adaptation responses are available for aquaculture, but some options, like translocation and technological responses may not be available to subsistence-based communities ( ''medium evidence'' ).

An example of eco-engineering-based adaptation option in seaweed aquaculture under climate change is

artificial upwelling, as shown by experiments and observations. Artificial upwelling powered by green energy (solar, wind, wave or tidal energy) to seaweeds (Jiao et al., 2014b; Zhang et al., 2015; Pan and Schimel, 2016) can moderate the amount of deep water upwelled to the euphotic zone to just meet the demands of nutrients and DIC by the seaweed for photosynthesis, while avoiding the acidification and hypoxia that often occur in natural upwelling systems (Jiao et al., 2018a; Jiao et al., 2018b) ( ''high confidence'' ). Such artificial upwelling based eco-engineering may also gradually release the ‘bomb’ of rich nutrients and hypoxia in the bottom water, which could otherwise breakout following storms (Daneri et al., 2012) ( ''high confidence'' ).

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===== 5.5.2.3.4 Coastal tourism =====

The coastal tourism economic sector is highly sensitive to climate change. Tourism response, in terms of mitigating carbon emissions and adapting to climate change impacts, are assessed here. Coastal tourism is likely to be impacted by ecosystem degradation and loss ( ''limited evidence, medium agreement'' ), which underscores the importance of nature-based tourism. An example of coastal erosion in Latin America illustrates this, whereby SLR interacting with non-climate change impacts including sand mining, inappropriate development and habitat destruction (e.g., mangroves), resulted in declines in tourism (Rangel-Buitrago et al., 2015). The management recommendation was appropriate legislation with a marine spatial planning emphasis, enforcement, sustainable funding mechanisms and support networks for decision making.

Climate change impacts upon tourism are nuanced and not restricted to just physical impacts on tourism establishments (Biggs et al., 2015). Understanding the drivers of tourist choices could help support adaptation in the industry through marine spatial planning processes (Papageorgiou, 2016). For example, in an survey ranking mitigation and adaptation responses in Greece, tourists prioritised rational energy use, energy efficiency and water saving measures (Michailidou et al., 2016b). Location specific information of tourist choices could help shape local industries. In one example from the Thailand dive industry, climate change adaptation responses of participants were reported to be based on misconceptions about climate change and personal observations (Tapsuwan and Rongrongmuang, 2015). To improve community-based adaptation, efforts aimed at broadening the level of awareness about climate change could improve decision making processes (Tapsuwan and Rongrongmuang, 2015). Tourist behaviour is shaped by changing ocean physical processes and degrading ecosystems at tourist destinations, which drive destination changes, economic flows and market share adjustments. (Bujosa et al., 2015; De Urioste-Stone et al., 2016).

It is very likely that climate change will have direct and nuanced impacts upon coastal tourism. Improving decision support frameworks ( ''low evidence, medium agreement'' ) for better-informed decision making tools could contribute towards increasing resilience in coastal tourism ( ''low evidence, limited agreement'' ).

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<span id="government-responses"></span>
===== 5.5.2.2.5 Government responses =====

Government responses included adopting and mainstreaming sustainability policies, including investments and policies for climate change (Aylett, 2015; Buurman and Babovic, 2016) and applying the precautionary principle in the absence of precise scientific guidance (Johnson et al., 2018). Developing adequate governance and management systems (Johnson et al., 2018), strengthening capacity (Gallo et al., 2017; Paterson et al., 2017), increasing cooperation (Nunn et al., 2014; Gormley et al., 2015) and aligning policies of local authorities (Porter et al., 2015; Gallo et al., 2017; Rosendo et al., 2018) could help to improve implementation (Sano et al., 2015; Elsharouny, 2016). This includes planning for MPAs and improving integrated coastal management (Abelshausen et al., 2015; Roberts et al., 2017; Rosendo et al., 2018) by incorporating climate science (Hopkins et al., 2016; Johnson et al., 2018) to optimise priority marine habitats (Gormley et al., 2015; Jones et al., 2018). An advantage of integrated coastal management is that it helps manage the interactions between multiple climate and non-climatic drivers of coastal ecosystems and sectors. Incorporating stakeholder participation with local knowledge and Indigenous knowledge could help to reduce the risk of maladaptation, and increase buy-in for implementation (Serrao-Neumann et al., 2013). Improving participatory processes strengthens governance decision making and flexible risk management processes (Gerkensmeier and Ratter, 2018; Rosendo et al., 2018), while stimulating bi-directional knowledge flow and improving social learning (Abelshausen et al., 2015).

Technology for environmental monitoring, for example using drones (Clark, 2017), web-based coastal information systems (Mayerle et al., 2016; Newell and Canessa, 2017), the Internet of Things and machine learning solutions promise to improve the local scale knowledge base, which should improve climate adaptation planning and resilience effort and environmental management decisions (Conde et al., 2015). Where such knowledge gaps persist, the implementation of climate change adaptation measures could proceed on the basis of a set of general principals of best practice (Sheaves et al., 2016; Thorne et al., 2017).

Benefits of effective government adaptation response includes the promotion of sustainable use, development and protection of coastal ecosystems (Rosendo et al., 2018) and the protection of biodiversity through setting appropriate conservation priorities (Gormley et al., 2015). Improved governance includes consideration of social processes in risk management (Gerkensmeier and Ratter, 2018; Rosendo et al., 2018) and improved systematic conservation planning (Johnson et al., 2018). At a local level, this translates into sustained service delivery (Aylett, 2015), improved rationality and effective policy making (Serrao-Neumann et al., 2013; Rosendo et al., 2018).

Improving the implementation and coordination of policies and improving integrated coastal management are both considered important climate change adaptation governance responses ( ''robust evidence, high agreement'' ), as are developing partnerships and building capacity ( ''medium evidence, high agreement'' ) and adopting or mainstreaming sustainability policies ( ''limited evidence, medium agreement'' ). Benefits include improved ecosystem resilience, better planning processes, implementation and policies (all ''limited evidence, medium agreement'' ).

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