Editing IPCC:AR6/WGII/Cross-Chapter-Paper-2 (section)

== CCP2.4 Enabling Conditions and Lessons Learned ==

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Here we distil enabling conditions and lessons learned from C&amp;S archetypes adapting to coastal risk (Table SMCCP2.1; Table SMCCP2.2; Sections 6.4; 9.9.4; 10.5; 10.6; 11.7; 11.8; 12.5.5; 13.6.2; 14.7.2; 15.6).

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=== CCP2.4.1 Enabling Behavioural Change ===

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Changing behaviours and practices are a critical enabler of adaptation in coastal C&amp;S. Behavioural enablers include using economic, informational, sociocultural and psychological incentives to motivate adaptation actions ( [[#van%20Valkengoed--2019|van Valkengoed and Steg, 2019]] ; [[#Gibbs--2020|Gibbs, 2020]] ), for example leveraging Indigenous knowledge and local knowledge (IKLK) and religious beliefs to incentivise adaptation ( [[#Hiwasaki--2014|Hiwasaki et al., 2014]] ; [[#Ford--2015|Ford et al., 2015]] ), implementing subsidies/bans to incentivise sustainable aquaculture ( [[#Condie--2014|Condie et al., 2014]] ; [[#Krause--2020|Krause et al., 2020]] ), providing localised flood warnings and forecasts to inform individual risk perceptions and risk management ( [[#Bruine%20de%20Bruin--2014|Bruine de Bruin et al., 2014]] ; [[#Gibbs--2020|Gibbs, 2020]] ) or incentivise risk insurance ( [[#Bradt--2019|Bradt, 2019]] ).

There is ''high evidence'' with ''medium agreement'' that public attitudes and perceptions of climate risks significantly influence individual adaptation behaviour across all coastal archetypes ( [[#Bradt--2019|Bradt, 2019]] ; [[#Buchanan--2019|Buchanan et al., 2019]] ; [[#Javeline--2019|Javeline et al., 2019]] ). Information on climate risks and impacts (e.g., flood warnings, SLR projections) strongly shapes public perceptions of climate risks. It is most effective at incentivising and enabling adaptation behaviour if provided on meaningful spatial and temporal scales, with guidance about how to interpret the information ( ''medium evidence'' , ''high agreement'' ; [[#Gibbs--2020|Gibbs, 2020]] ; [[#Cools--2016|Cools et al., 2016]] ). Further, there is ''medium evidence'' , ''high agreement'' that integrating climate information with existing knowledge systems, such as local norms and beliefs and IKLK, is critical to improve public acceptability and develop context-specific solutions ( [[#Ford--2015|Ford et al., 2015]] ).

A second key enabler of coastal adaptation behaviour is self-efficacy or belief in one’s capacity to undertake adaptation. There is ''medium evidence'' , ''high agreement'' that high risk perception is in itself insufficient to motivate people to undertake adaptation ( [[#Fox-Rogers--2016|Fox-Rogers et al., 2016]] ; [[#Roder--2019|Roder et al., 2019]] ; [[#Gibbs--2020|Gibbs, 2020]] ) and needs to be supplemented with supportive policy and financial provisions to enable adaptation ( [[#Fox-Rogers--2016|Fox-Rogers et al., 2016]] ).

Third, there is ''medium evidence'' on how trust in state-led, planned adaptation measures can hinder or enable individual adaptation ( [[#van%20Valkengoed--2019|van Valkengoed and Steg, 2019]] ; [[#Schneider--2020|Schneider et al., 2020]] ). As an enabler, trust in early warnings can mitigate flood risk by incentivising evacuation ( [[#Binh--2020|Binh et al., 2020]] ) and high trust can help overcome uncertainty attached to projected climate impacts and/or adaptation decisions ( [[#Frederiksen--2014|Frederiksen, 2014]] ). As a barrier, low trust can disincentivise adaptation, for example willingness to pay for flood insurance ( [[#Roder--2019|Roder et al., 2019]] ) or public support for managed retreat ( [[#Hanna--2020|Hanna et al., 2020]] ). Paradoxically, high trust in existing adaptation measures can reduce people’s perceived need for ongoing adaptation (e.g., levees potentially reducing individual flood-proofing actions). Adaptation decisions also manifest ‘single-action bias’, with modest cost-adaptation actions in the present disincentivising further adaptation ( [[#Buchanan--2019|Buchanan et al., 2019]] ).

Several tools to incentivise adaptation behaviour are being tested around the world. For example, nudges and boosts [[#footnote-000|3]] are being experimented with to shape individual risk beliefs and the demand for flood insurance ( [[#Bradt--2019|Bradt, 2019]] ); ordinances are being used to ban, authorise or limit certain activities ( [[#Herrick--2018|Herrick, 2018]] ); subsidies and financial support are being used to incentivise adaptation such as subsidised beach nourishment ( [[#McNamara--2015|McNamara et al., 2015]] ); and zoning restrictions and building codes restrict or guide climate-resilient infrastructural development ( [[#Schneider--2020|Schneider et al., 2020]] ). Overall, the literature affirms that behavioural interventions are more readily taken up if they are aligned with cultural practices, norms and beliefs; are on temporal scales within peoples’ planning horizons; and if they build upon relationships of trust and legitimacy ( [[#Donner--2014|Donner and Webber, 2014]] ; [[#Herrick--2018|Herrick, 2018]] ; [[#Schneider--2020|Schneider et al., 2020]] ).

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=== CCP2.4.2 Finance ===

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Lack of financial resources is a key constraint affecting all coastal archetypes ( ''high confidence'' ; Table SMCCP2.2). Adaptation to coastal hazards is costly: the global costs of protecting coastal areas with levees (annual investment and maintenance costs) are estimated at USD 12–71 billion for 2100 with SLR up to 1.2 m ( [[#Hinkel--2014|Hinkel et al., 2014]] ). Broadly speaking, it is cost effective to contain coastal hazard risk in the short to medium term in densely populated wealthy localities by using protective works, but such measures are unaffordable in dispersed poorer coastal C&amp;S ( [[#Lincke--2018|Lincke and Hinkel, 2018]] ).

Archetypes with high adaptive capacity may currently have financial resources to meet adaptation needs, but such funding may be unsustainable in the long term. In Catalonia, while public funds are currently used to finance beach nourishment, these costs will increase with SLR and it is unclear whether public finance will remain a feasible source ( [[#Hinkel--2018|Hinkel et al., 2018]] ). Even in relatively richer municipalities, financing adaptation is constrained by other urban priorities ( [[#Bisaro--2018|Bisaro and Hinkel, 2018]] ). In Europe, shifting responsibilities from national governments to transnational and local actors has resulted in reduced national budgets for coastal adaptation investment and increased pressure on local authorities to raise public funds for adaptation without alienating electoral bases ( [[#Bisaro--2018|Bisaro and Hinkel, 2018]] ).

Locations in the Global South have limited public budgets allocated to coastal adaptation and may rely on international donor aid ( [[#Donner--2016|Donner et al., 2016]] ; [[#Araos--2017|Araos et al., 2017]] ). Such aid is often inconsistent and short term, which limits long-term maintenance of the knowledge, equipment and infrastructure needed to sustain adaptation measures beyond initial funding periods ( [[#Weiler--2018|Weiler et al., 2018]] ; [[#Thomas--2020|Thomas et al., 2020]] ), with resultant negative consequences in places as different as Kiribati ( [[#Donner--2014|Donner and Webber, 2014]] ) and Bangladesh ( [[#Hinkel--2018|Hinkel et al., 2018]] ). Donor-funded adaptation programs aimed at promoting behavioural change, for example through coastal planning or new decision-making systems, require enduring training and institutional capacity, which is difficult to upkeep after aid is depleted. Donor funding is often project based and there are few avenues available to fund the additional permanent and long-term staff needed to bolster climate change institutions. Without funding to support additional staff, existing institutions often lack the human capacity and resources needed for coastal adaptation ( [[#Ziervogel--2014|Ziervogel and Parnell, 2014]] ).

C&amp;S in the Global South also face financial challenges in addressing loss and damage due to climate-induced slow-onset and extreme events. Financial support to address both quantifiable damages and non-economic losses through measures such as climate-resilient reconstruction after extreme weather events as well as national and local-level emergency contingency funds are lacking, which has been an issue of contention in international policy arenas ( [[#Bahinipati--2017|Bahinipati et al., 2017]] ; [[#Wewerinke-Singh--2020|Wewerinke-Singh and Salili, 2020]] ; [[#Martyr-Koller--2021|Martyr-Koller et al., 2021]] ).

While coastal adaptation has largely been viewed as the responsibility of governments, private finance is increasingly recognised as necessary to help close the coastal adaptation funding gap ( [[#Ware--2020|Ware and Banhalmi-Zakar, 2020]] ). Financial arrangements for coastal adaptation measures that align public-actor and private-investor interests are suitable for a range of budgets, from USD 10,000 to 100 million ( [[#Bisaro--2018|Bisaro and Hinkel, 2018]] ). Private equity instruments that involve real estate development companies have already been successfully implemented and are most effective in urban areas with high-value real estate development ( [[#Chiang--2017|Chiang and Ling, 2017]] ). Public–private partnership equity instruments that engage construction and real estate developers have been successful for small- to medium-scale infrastructural projects. While public–private partnership bonds and public bonds have the potential to align public actors and private investors, such instruments require de-risking of coastal adaptation through enabling economic policy instruments, such as concessional loans ( [[#Bisaro--2018|Bisaro and Hinkel, 2018]] ).

Explicitly identifying the benefits, or goods and services, that are provided by coastal adaptation is critical to supplement limited government funds and engage a broader set of financial tools and actors ( [[#Woodruff--2020|Woodruff et al., 2020]] ). Matching goods and services provided by particular adaptation strategies to specific beneficiaries helps to identify the range of fair and equitable financial tools. In the Netherlands, public fundings through state, regional and local entities have independent tax revenue systems to provide the funding needed to maintain flooding infrastructure ( [[#Hinkel--2018|Hinkel et al., 2018]] ).

Given the high costs of coastal adaptation, benefit-to-cost ratios (BCR) are often used to determine the value of investing in adaptation. BCR are high for urbanised coastal areas with high concentrations of assets (13% of the world’s coastline), covering 90% of the global coastal floodplain population and 96% of assets in the global coastal floodplain ( [[#Lincke--2018|Lincke and Hinkel, 2018]] ). A global assessment shows a BCR for investing in flood protection of up to ~120 ( [[#Tiggeloven--2020|Tiggeloven et al., 2020]] ). For Europe, at least 83% of flood damages could be avoided by elevating dikes along ~23–32% of Europe’s coastline and BCR vary from 8.3 to 14.9, with higher ratios for higher concentration pathways ( [[IPCC:Wg2:Chapter:Chapter-13#13.2|Section 13.2]] ; [[#Vousdoukas--2020a|Vousdoukas et al., 2020a]] ). Globally, 40% of damages can be reduced with levees of 1 m and costs lower than avoided damage ( [[#Tamura--2019|Tamura et al., 2019]] ). For a mix of expensive storm surge barriers, nature-based solutions and flood-proofing measures for New York City, [[#Aerts--2014|Aerts et al. (2014)]] found BCRs &lt;1 for the current situation, but &gt;2 for a SLR scenario of +1 m.

However, BCR values may be low and adaptation investment may not be financially viable for small coastal settlements, less densely populated poorer coasts or isolated communities ''(medium confidence).'' Considering BCRs of protection and coastal migration across a range of SLR and Shared Socioeconomic Pathways (SSP) scenarios for the 21st century, a higher BCR was found for protection of only 3% of the global coastline protecting 78% of the coastal population and 92% of global coastal floodplain assets, while for the remaining coasts, coastal migration was estimated to be optimal in terms of economic costs ( [[#Lincke--2021|Lincke and Hinkel, 2021]] ). Considering coastal migration as part of the solution space could lower global costs in investment and maintenance for SLR protection by a factor of 2–4 in the 21st century, but would result in large land losses and high levels of migration for South and Southeast Asia in particular, and in relative terms, small island nations would suffer most. The need to consider place attachment, community relationships, livelihoods and the spiritual and cultural significance of settlements limits the application of BCR as a tool for coastal adaptation decisions in these contexts ( [[#Thomas--2020|Thomas and Benjamin, 2020]] ). Moreover, there is limited knowledge on trade-offs, including BCR, of alternative adaptation options and pathways at a global to regional scale, in particular over the long term (beyond 2100).

Even where BCR is high, finance may be inaccessible, as it is challenging to convert the long-term benefits of adaptation into the revenue streams that may be needed to initially finance adaptation investments ( [[#Hinkel--2018|Hinkel et al., 2018]] ). For example, in Ho Chi Minh City, Vietnam, despite high BCR, high costs of flood protection (USD 1.4–2.6 billion) have prevented such adaptation measures from being implemented ( [[#Hinkel--2018|Hinkel et al., 2018]] ; [[#Cao--2021|Cao et al., 2021]] ). Moreover, drawing from places as distinct as small communities in Fiji ( [[#Neef--2018|Neef et al., 2018]] ) and Belize ( [[#Karlsson--2015|Karlsson and Hovelsrud, 2015]] ), and megacities like New York City and Shanghai ( [[#Oppenheimer--2019|Oppenheimer et al., 2019]] ), BCR provides only a limited view and consideration of feasibility, effectiveness, efficiency, equity, culture, politics and power, and attachment to place has a greater chance of fostering CRD ( ''high confidence'' ).

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=== CCP2.4.3 Governance ===

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An array of climatic and non-climatic perils ( [[#Le%20Cozannet--2017|Le Cozannet et al., 2017]] ) present coastal communities and their governing authorities with immense governance and institutional challenges that will become progressively more difficult as sea level rises ( ''high confidence'' ; [[#Wallace--2017|Wallace, 2017]] ; [[#Leal%20Filho--2018|Leal Filho et al., 2018]] ; [[#Oppenheimer--2019|Oppenheimer et al., 2019]] ). Yet a study of public provisions for coastal adaptation in 136 of the largest coastal port–urban agglomerations across 68 countries found no policy implementation in 50% of the cases; in 85% of cases, adaptation actions are not framed by current impacts or future risks, and formal efforts are recent and concentrated in more developed settings ( [[#Olazabal--2019|Olazabal et al., 2019]] ; [[#Olazabal--2021|Olazabal and Ruiz De Gopegui, 2021]] ), thus underscoring a persistent coastal adaptation gap. Translating these challenges into enabling governance conditions is difficult, but instructive lessons are being learned and are summarised (from Table SMCCP2.4) for archetypal C&amp;S in Tables CCP2.1 and 2.2.

We start with a synopsis of governance settings within which coastal adaptation and CRD choices are made, and spotlight factors hindering and enabling translation of adaptation into practice. Then, building upon and extending the SROCC analysis of enablers and lessons learned in responding to SLR ( [[#Oppenheimer--2019|Oppenheimer et al., 2019]] ), we assess key governance challenges, related enablers and lessons learned (Tables CCP2.1, Section CCP2.2).

Governance arrangements and practices are embedded in the sociopolitical and institutional fabric of coastal C&amp;S ''.'' Consequently, barriers and enablers for adapting to climate change at the coast and charting pathways for CRD reflect more general constraints and opportunities ( ''high confidence'' ; [[#Meerow--2017|Meerow, 2017]] ; [[#Rocle--2018|Rocle and Salles, 2018]] ; [[#Rosendo--2018|Rosendo et al., 2018]] ; [[#Di%20Giulio--2019|Di Giulio et al., 2019]] ; [[#Hölscher--2019|Hölscher et al., 2019]] ; [[#Van%20Assche--2020|Van Assche et al., 2020]] ; [[#Williams--2020|Williams et al., 2020]] ). Local-level action is often constrained: 231 cities in the USA report weak leadership, lack of funding and staffing, and low political will ( [[#Fu--2020|Fu, 2020]] ). A meta-analysis of coastal municipal planning documents in Australia shows that few localities have moved beyond risk assessment ( [[#Bradley--2015|Bradley et al., 2015]] ). Coastal C&amp;S tend to prefer strategies that protect and accommodate existing coastline assets in the sense of a ‘fix and forget’ approach ( [[#Gibbs--2015|Gibbs, 2015]] ), rather than enduring proactive adaptation ( [[#Cooper--2014|Cooper and Pile, 2014]] ).

Many C&amp;S, especially in the Global South, already face high exposure to coastal risks and development constraints associated with poverty and socioeconomic inequality, lack of transparent resource allocation mechanisms and low political will ( ''high confidence'' ; [[#Di%20Giulio--2019|Di Giulio et al., 2019]] ; [[#Nagy--2019|Nagy et al., 2019]] ; [[#Pasquini--2020|Pasquini, 2020]] ; [[#Lehmann--2021|Lehmann et al., 2021]] ) ''.'' Research from across South America notes inadequate regulatory frameworks, missing data and information, widespread coastal ecosystem degradation and complex interactions between natural disasters and civil conflict ( [[#Villamizar--2017|Villamizar et al., 2017]] ; [[#Nagy--2019|Nagy et al., 2019]] ). Coastal climate risks in the Global South are often compounded by ongoing land-use management conflicts and other pressures including informal land uses, unregulated and/or inadequate infrastructure/building development, public health priorities such as combating Dengue fever, inadequate income diversification, low education levels and political marginalization of communities historically not represented in the urban development process ( [[#Barbi--2014|Barbi and Ferreira, 2014]] ; [[#Salik--2015|Salik et al., 2015]] ; [[#Cabral--2017|Cabral et al., 2017]] ; [[#Goh--2019|Goh, 2019]] ). There are also entrenched socioeconomic inequalities leading to the maldistribution of adaptation actions and benefits in the Global North ( [[#Gould--2018|Gould and Lewis, 2018]] ; [[#Keenan--2018|Keenan et al., 2018]] ; [[#Ranganathan--2019|Ranganathan and Bratman, 2019]] ; [[#Yumagulova--2020|Yumagulova, 2020]] ; [[#Long--2021|Long et al., 2021]] ).

To address the myriad governance challenges attributed to low awareness, low skills, scalar mismatches, and high socioeconomic inequality and coastal vulnerability, post-AR5 research highlights enablers of more innovative approaches to bridge capacity, policy and financial deficits ( [[#Reiblich--2019|Reiblich et al., 2019]] ), and facilitate more proactive implementation of coastal adaptation actions (Table SMCCP2.2; [[#Fu--2020|Fu, 2020]] ). A survey of NGOs, state and local government across Alaska, Florida and Maryland in the USA found that perceived risk, uncertainty and trust in support for climate adaptation varied across two stages of adaptation, that is between support for the development of plans and willingness to allocate human and financial resources to implement plans ( [[#Kettle--2016|Kettle and Dow, 2016]] ). To bridge this gap, [[#Cinner--2018|Cinner et al. (2018)]] suggest the need to build capacity across five domains: the assets that people can draw upon in times of need; the flexibility to change strategies and interventions; the ability to organise and act collectively; learning to recognise and respond to change (especially as important thresholds are approached); and the agency to determine whether to change or not, and to then take prudent action.

Effective and accountable local leadership can help to mobilise capacities, resources and climate awareness within coastal C&amp;S. Strong leadership is associated with agenda-setting authorities and the ability to navigate complex institutional interests towards more strategic planning efforts ( ''high confidence'' ; [[#Ferguson--2013|Ferguson et al., 2013]] ; [[#Anguelovski--2014|Anguelovski et al., 2014]] ; [[#Chu--2017|Chu et al., 2017]] ; [[#Valdivieso--2018|Valdivieso and Andersson, 2018]] ; [[#Fink--2019|Fink, 2019]] ; [[#Ndebele-Murisa--2020|Ndebele-Murisa et al., 2020]] ). Policy leadership can positively influence the motivation and initiative of municipal officers ( [[#Lassa--2014|Lassa and Nugraha, 2014]] ; [[#Wijaya--2020|Wijaya et al., 2020]] ), whilst local leadership is needed integrate coastal management, disaster management and climate adaptation mandates ( [[#Rosendo--2018|Rosendo et al., 2018]] ).

Inclusive decision-making arrangements can enable participation, local ownership, and further equity in crafting coastal adaptation plans and policies ( [[#Chu--2016|Chu et al., 2016]] ). Inclusion of diverse stakeholders can help improve awareness of adaptation needs; help to bridge existing social inequalities in decision-making about adaption needs, options and outcomes; close the gap between formal and informal institutions and engage indigenous forms of decision-making, which often associate climate risks with livelihood, housing and employment stressors ( [[#Ziervogel--2016|Ziervogel et al., 2016]] ; [[#Fayombo--2020|Fayombo, 2020]] ). For example, research from Pacific island states ( [[#Nunn--2017|Nunn et al., 2017]] ) and coastal Arctic zones ( [[#Romero%20Manrique--2018|Romero Manrique et al., 2018]] ) highlights the need to engage with indigenous environmental knowledge. Case studies from Indonesia, the Philippines and Timor-Leste show that Indigenous knowledge and local knowledge and customary laws can support environmental awareness, strengthen social cohesion and help communities to better respond to climate impacts ( [[#Hiwasaki--2015|Hiwasaki et al., 2015]] ). Research from coastal Cambodia shows that inclusive governance arrangements can target empowerment of the most vulnerable groups to facilitate better adaptation behaviour and mainstream adaption knowledge through both formal and informal education at the community level ( [[#Ung--2016|Ung et al., 2016]] ).

The law is key to governing climate risks in C&amp;S, including regulating exposure to coastal hazards; facilitating accountable decision-making; funding arrangements, liabilities and resolving disputes; and also for securing human rights ( ''high confidence'' ; [[#Setzer--2019|Setzer and Vanhala, 2019]] ; [[#Averill--2020|Averill, 2020]] ). However, it has limits and can be both an adaptation enabler and barrier ( [[#Green--2015|Green et al., 2015]] ; [[#Cosens--2017|Cosens et al., 2017]] ; [[#Craig--2017|Craig et al., 2017]] ; [[#DeCaro--2017|DeCaro et al., 2017]] ). Contemporary legal practice has not enabled effective adaptation in part because SLR affects compensable property rights that are secured by the law, and which generally trump concerns about public safety, resilience and sustainability ( [[#Reiblich--2019|Reiblich et al., 2019]] ). Private property rights can be used as both a sword and a shield to privilege dominant interests by undermining land use policies, plans and implementation efforts intended to promote integrated coastal management and risk reduction ( [[#O’Donnell--2019|O’Donnell et al., 2019]] ; [[#Reiblich--2019|Reiblich et al., 2019]] ). Climate change litigation has proliferated over the past decade ( [[#Setzer--2019|Setzer and Vanhala, 2019]] ), addressing, among other things, failures to prepare for or adapt to climate change, and to secure human rights ( [[#Peel--2018|Peel and Osofsky, 2018]] ). Reflexive and adaptive law that accounts for the distinctive features of coastal hazard risk and associated governance imperatives builds coastal C&amp;S adaptive capacity and resilience ( ''high confidence'' ; [[#Garmestani--2013|Garmestani and Benson, 2013]] ; [[#Cosens--2017|Cosens et al., 2017]] ; [[#DeCaro--2017|DeCaro et al., 2017]] ). Procedural justice, due process and use of substantive standards instead of rules provide legal stability and enable adaptation ( [[#Craig--2017|Craig et al., 2017]] ). Coastal adaptation efforts are ultimately implemented through C&amp;S actions that are enabled or constrained by prevailing legislative, executive and judicial provisions and practices, which differ significantly across jurisdictions ( [[#He--2018|He, 2018]] ). In practice, the ‘coastal lawscape’ is made up of interconnected cultural normative, political and legal systems that need to be understood holistically to enable coastal adaptation in C&amp;S ( [[#O’Donnell--2021|O’Donnell, 2021]] ).

Tables CCP2.1 and CCP2.2 summarise key insights about key governance challenges facing archetypal coastal C&amp;S around the world as well as associated critical enablers and lessons learned to address climate change-compounded coastal hazard risk (based on synthesis of Table SMCCP2.3).

In sum, prospects for addressing climate risk in archetypal coastal C&amp;S around the world depend on the extent to which societal choices—and associated governance processes and practices—address the drivers and root causes of exposure and social vulnerability ( ''very high confidence'' ) ''.'' Coastal C&amp;S are more able to address these challenges when authorities work with local communities and vulnerable groups in particular, and with stakeholders from the local to national levels and beyond, to chart adaptation pathways that enable sustained reduction in the exposure and vulnerability of those most at risk ''(very high confidence'' ; Cross-Chapter Box SLR in Chapter 3; [[#Magnan--2019|Magnan et al., 2019]] ; [[#Oppenheimer--2019|Oppenheimer et al., 2019]] ). Unlocking potential enablers for locally appropriate and effective adaptation is difficult because many drivers and root causes of coastal risk are historically and institutionally embedded ''(high confidence'' ; [[#Thomas--2019|Thomas et al., 2019]] ). Charting credible, salient and legitimate adaptation pathways is consequently a struggle in reconciling divergent worldviews, values and interests ( [[#Sovacool--2018|Sovacool, 2018]] ; [[#Mendenhall--2020|Mendenhall et al., 2020]] ; [[#Bowden--2021a|Bowden et al., 2021a]] ; [[#Bowden--2021b|Bowden et al., 2021b]] ). Unlocking the productive potential of conflict is foundational for transitioning towards pathways that foster CRD ''(high confidence'' ; [[#Abrahams--2017|Abrahams and Carr, 2017]] ; [[#Harris--2018|Harris et al., 2018]] ; [[#Sharifi--2020|Sharifi, 2020]] ). But this can be especially challenging for low-lying coastal C&amp;S characterised by degraded coastal ecosystems susceptible to climate change impacts as well as pronounced inequity and governance constraints ''(high confidence'' ; [[#Esteban--2017|Esteban et al., 2017]] ; [[#Jones--2020|Jones et al., 2020]] ).

'''Table CCP2.1 |''' Governance challenges and critical enablers for addressing coastal hazard risk in C&amp;S

{| class="wikitable"
|-
! '''Key governance challenges'''

! '''Critical enablers for C&amp;S to address coastal hazard risk'''

|-
| rowspan="2"| '''Complexity:''' climate change compounds non-climatic hazard risks facing coastal C&amp;S in interconnected, dynamic and emergent ways for which there are no simple solutions.

| Draw on '''multiple knowledge systems''' to co-design and co-produce more acceptable, effective and enduring responses.

|-
| Build '''governance capacity''' to tackle complex problems.

|-
| rowspan="2"| '''Time horizon and uncertainty:''' The future is uncertain, but climate change will continue for generations and cannot be addressed by short-term (e.g., 1–10 years) responses alone.

| Adopt a '''long-term view''' but take action now. '''Keep options open''' to adjust responses as climate risk escalates and circumstances change.

|-
| '''Avoid''' new development commitments in exposed locations. Enable managed retreat in most at-risk locations by '''anticipatory actions''' , e.g., secure funds, legal provisions for buy-outs, resettlement, etc.

|-
| rowspan="2"| '''Cross-scale and cross-domain coordination:''' Decisions bound by jurisdictional and sectoral boundaries fail to address linkages within and between coastal ecosystems and C&amp;S facing interconnected climate change-compounded impacts and risk.

| Develop networks and linkages within and between different governance scales and levels and across policy domains and sectors, to improve '''coordination''' , build trust and legitimise decisions.

|-
| Build '''shared understanding''' and enable locally appropriate responses through experimentation, innovation and social learning.

|-
| rowspan="2"| '''Equity and social vulnerability:''' Climate change compounds everyday inequity and vulnerability in coastal C&amp;S, making it difficult to disentangle and address social drivers and root causes of risk.

| Recognise political realities and '''prioritise vulnerability''' , justice and equity concerns to enable just, impactful and enduring outcomes.

|-
| Strengthen '''community capabilities''' to respond to coastal hazard risk, using external assistance and government support if necessary.

|-
| rowspan="2"| '''Social conflict:''' Coastal C&amp;S will be the focal point of contending views about appropriate climate responses, and face the challenge of avoiding destructive conflict and realising its productive potential.

| Design and facilitate '''tailor-made participation processes''' , involving stakeholders early and consistently from negotiating responses to implementation.

|-
| Create '''safe arenas of engagement''' for inclusive, informed and meaningful deliberation and collaborative problem-solving.

|}

'''Table CCP2.2 |''' Lessons learned from efforts to address coastal hazard risk

{| class="wikitable"
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! '''Lessons to address governance challenges and unlock enablers'''

! '''Archetypal C&amp;S initiatives, constraints aside'''

|-
| '''Complexity: multiple knowledge systems'''

* Reveal dynamic complexity drawing on multiple sources of locally relevant evidence.
* Use and integrate local, Indigenous and scientific knowledge.
* Include marginalised voices and knowledge of vulnerable groups, women, young people, etc.
* Build shared understanding through storytelling.
* Bridge gaps between science, policy and practice by experimenting with novel approaches and working across organisational, sectoral and institutional boundaries.

| '''Seychelles (0.1 million; open coast):''' Science–policy–local knowledge partnerships to co-produce usable information for decision-making.

'''Dhaka, Bangladesh (21 million; delta):''' Climate change is national priority. Partnering with the Netherlands to develop long-term data plans.

'''Jakarta, Indonesia (10.8 million; delta):''' Community-based efforts to foster mutual assistance and self-organisation.

'''Utqiagvik (formerly Barrow) Alaska, USA (0.04 million; Arctic, open coast):''' Using local knowledge and historical precedent of transformative change to integrate local and scientific knowledge.

|-
| '''Complexity: governance capacity'''

* Joined-up visionary leadership is key, e.g., cabinet- and C&amp;S-level commitments to long-term implementation.
* Translate political will into substantial dedicated budgets to build government capacity to tackle complex problems.
* Use flexible approaches to build resilience, e.g., independent agency alongside traditional administrative bodies.
* Counter deadlocks due to short-term priorities and vested interests with long-term perspectives, considering plausible scenarios and incentivising novel solutions.
* Translate national requirements into local action with enabling provisions for tailored local policy and practice.
* Tackle emergent problems by setting up enduring monitoring and lesson-learning processes.
* Governance arrangements reconcile competing interests in an inclusive, timely and legitimate manner.
* Make visible and reflect on underlying reasons for policy actions/inaction, including values, attitudes and taken-for-granted habits influencing problem-solving capability.

| '''Singapore (5.6 million; open coast):''' Integrated approach across ministries committing to long-term adaptation (and mitigation goals) by 2030.

'''Rotterdam, the Netherlands (0.65 million; delta):''' Delta Programme, supported by law, administrative arrangements and a €1 bill. pa budget to 2029.

'''Florianopolis, Santa Catarina Island, Brazil (1.2 million; mixed):''' Building knowledge hub via public–private–civil society partnerships.

'''Nassau, Bahamas (0.275 million; open coast, small island):''' Identifying responsibilities, accessing funding and preparing adaptation plans drawing on evidence-based studies.

'''Shanghai (27 million; estuary), China:''' Contain risk by combining long-term planning, political will, national and municipal provisions, and technical capability.

'''Can Tho City, Vietnam (0.4 million; delta):''' Engage international donors and research community.

|-
| '''Time horizon and uncertainty: long-term view'''

* Establish national policies and guidance with a long-term view (e.g., 100 years) that enable action now.
* Develop shared medium- (10–50 years) to long-term vision (100+ years).
* Use an adaptation-pathways approach to make short-term decisions consistent with long-term goals.
* Meaningfully involve stakeholders, e.g., involve representatives in decision-making.
* Address power imbalances and human development needs, e.g., in goal setting and process design.
* Reconcile divergent perspectives through tailored responses.

| '''Napier (0.07 million), Hawkes Bay (0.18 million; open coast), New Zealand:''' National law compels local authorities to take a 100-year perspective; 2100 Strategy accounts for dynamic complexity and uncertain future through adaptation pathways.

'''Shanghai, China (27 million; estuary):''' Plans up to 2100, strong national and municipal focus on climate change, and access to technical expertise.

'''Dhaka, Bangladesh (21 million; delta):''' Long-term adaptation plans through to 2100.

|-
| '''Time horizon and uncertainty: avoidance and anticipatory action'''

* Avoid development in exposed localities using spatial plans.
* Use window of opportunity created by extreme events.
* Prepare pre-event plans and tailor risk reduction and resilience building post disaster.
* Reveal political pressures and opposition that hamper efforts to address intolerable risk and unacceptable impacts.

| '''Rotterdam, the Netherlands (0.65 million; delta):''' Delta Programme promotes ‘living with water’, allowing and managing urban flooding.

'''Napier (0.07 million), Hawkes Bay, New Zealand (0.18 million, open coast):''' Regulatory provisions discourage new development in high-risk locations; strategy sequences adaptation interventions.

'''Florianopolis, Santa Catarina Island, Brazil (1.2 million; mixed):''' Research reveals unregulated ad hoc development in at-risk locations preventing effective adaptation.

|-
| '''Cross-scale and cross-domain coordination: coordination'''

* Collaborative projects involve state and non-state actors.
* Multi-lateral agreements, e.g., between neighbouring countries, coastal regions and C&amp;S.
* Connect people, organisations and communities through boundary-spanning organizations.
* Leadership by central actors with capable teams is key.
* Mobilise the capabilities of communities and non-state actors.
* Address policy inconsistencies and clarify roles and responsibilities.
* Secure national and regional resources to support local efforts.
* Use measures to promote interaction, deliberation and coordination to manage spill-over effects.
* Strengthen linkages between formal (e.g., regulatory) and informal (e.g., traditions and rituals) institutions, e.g., through information sharing.
* Use spatial coordination mechanisms, e.g., land-use planning, to translate national and regional provisions into local competencies.

| '''Seychelles (0.1 million; open coast, small island):''' Cross-sectoral and institutional collaboration to improve use of limited financial resources; community-based and ecosystem-based adaptation to bridge adaptation and mitigation and improve coordination.

'''Florianopolis, Santa Catarina Island, Brazil (1.2 million; mixed):''' Effective local climate action hampered by governance constraints and weak federal leadership.

'''Cape Town, South Africa (4.6 million; mixed):''' Multi-level climate governance advanced at local-provincial level, but political turf battles hamper national–provincial–local progress.

|-
| '''Cross-scale and cross-domain coordination: shared understanding'''

* Prioritise social learning and shared understanding, e.g., information accessible to all, irrespective of education, language, etc.
* Account for local history, culture and politics through engagement, experimentation and innovation.
* Generate socioeconomic, livelihood and climate development co-benefits.
* Leverage national and trans-national community and local authority networks.

| '''Cape Town, South Africa (4.6 million; mixed):''' Capable local leaders collaborate with researchers in municipality-initiated community-based adaptation. Translating plans into action challenging given ‘everyday’ vulnerability exacerbated by climate change impacts.

'''New York City, USA (23.5 million; mixed):''' State and city government work with communities to build adaptive capacity and resilience; drawing on technical capabilities but many challenges.

|-
| '''Equity and social vulnerability: address vulnerability'''

* Expose drivers and root causes of injustice, structural inequity and vulnerability.
* Link human development concerns, risk reduction, resilience and adaptation.
* Raise awareness and public support for actions that are just and equitable.
* Understand discriminatory drivers (e.g., on racial grounds) of coastal land-use patterns and risk.
* Address barriers facing marginalised groups.
* Use inclusive planning, decision-making and implementation processes that give voice to vulnerable people.

| '''Cape Town, South Africa (4.6 million; mixed):''' Adaptation framed by apartheid legacy; focus on reducing vulnerability, public safety and securing critical infrastructure and community assets.

'''Maputo-Matola, Mozambique (3 million; mixed):''' Livelihood opportunities compromised by ecological degradation compelling community DIY coping in face of severe poverty and vulnerability, weak governance and institutional capacity, and reliance on donors.

'''New York City, USA (23.5 million; estuary):''' Hurricane Sandy (2012) focused attention on climate risk and the plight of exposed and vulnerable people, and sparked adaptation action.

|-
| '''Equity and social vulnerability: community capabilities'''

* Raise vulnerability and risk awareness and understanding; build community capability and leverage external support by working with professionals, academics, local NGOs, journalists and activists.
* Secure rights of vulnerable groups through court action where necessary.
* Integrate traditional community responses with local government efforts.
* Ensure gender equity, e.g., representation on planning and decision-making bodies.

| '''Monkey River Village, Belize (200 people; estuary):''' Remote indigenous community; capacity to tackle erosion enabled by interventions by researchers, journalists and local NGOs to secure media and political attention after hurricane damage.

'''Accra, Ghana (2.5 million; delta):''' Household adaptation mediated by local government flood-mitigation efforts; need better early warning and maintenance of local stormwater to prevent flooding.

'''Lagos, Nigeria (14 million; open coast):''' Building adaptive capacity to overcome ‘everyday’ vulnerability and poverty severely challenging.

|-
| '''Social conflict: tailor-made participation'''

* Create opportunities for integrative and inclusive solutions.
* Use conflict-resolution mechanisms.
* Appoint independent facilitators/mediators and involve officials as ‘bureaucratic activists’ to improve inclusivity and iterative and reflexive engagement.
* Align informal participatory processes with statutory processes and government practices.
* Sustain engagement by securing resources for local use and aligning activities with political and bureaucratic cycles.
* Involve historically disadvantaged and socially vulnerable groups, e.g., accessible meeting locations/venues, local languages and culturally appropriate meeting protocols.
* Involve local leaders who will champion adaptation and help mainstream findings to be integrated into C&amp;S decision-making.
* Inclusive processes help address conflict and drivers of vulnerability and promote just adaptation

| '''Napier (0.07 million), Hawkes Bay, New Zealand (0.18 million, open coast):''' Collaboration between local authorities and Indigenous People (Māori) involving stakeholders led to co-designed long-term strategy with implementation commitment.

'''Manila, Philippines (14 million; open coast):''' Metro-wide planning and infrastructure provisions that foster climate justice and resilience explored, with community-based actions.

|-
| '''Social conflict: safe arenas of engagement'''

* Use flexible and enabling processes based in local institutions that are robust and fair, supported by governing authorities.
* Attend to local social dynamics and reduce elite domination.
* Use local and Indigenous knowledge and science.
* Use institutional improvisation to address local concerns.
* Use trusted independent facilitators.
* Incentivise participation by disadvantaged groups.
* Focus on improving risk literacy, optimism and capacity for joint problem-solving.
* Use joint, collaborative activities to facilitate public dialogue, and secure institutional support for action.
* Enable ongoing deliberation and social learning.
* Make continual adjustments as circumstances change, e.g., build shared understanding about locally relevant thresholds beyond which alternative courses of action need to be actioned.

| '''Napier (0.07 million), Hawkes Bay, New Zealand (0.18 million, open coast):''' Active involvement of local communities, Indigenous People (Māori) and research community to co-produce fit-for-purpose long-term coastal hazard risk strategy.

'''Rotterdam, the Netherlands (0.65 mill.; delta):''' Delta Programme institutionalised multi-level adaptation governance with strong accountability mechanisms.

'''Greater London, UK (8.9 mill.; estuary):''' Long-term provisions for at-risk Thames Estuary including major protective works, embedded in Greater London Spatial Development Plan and London Climate Change Partnership, championed by strategic leadership and supported by the public and strong technical capability.

|}

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=== CCP2.4.4 Enabling Climate Resilient Development for Cities and Settlements by the Sea ===

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The above critical enablers and lessons learned from around the world establish a strong foundation for charting pathways for CRD in coastal C&amp;S. These pathways will necessarily vary in different C&amp;S, and synergies and commonalities within different coastal archetypes can be leveraged. Pivotal is recognition of the narrow window of time remaining to translate embryonic risk assessment and adaptation planning into concerted implementation efforts. C&amp;S by the sea could be the centres of innovation that lead the way to advancing SDGs through to 2030 and CRD beyond this decade (see [[IPCC:Wg2:Chapter:Chapter-2#2.1.1|Section 2.1.1]] ).

This cross-chapter paper shows that a range of adaptation solutions, hard and soft protection, nature-based measures, accommodate, advance, retreat and behavioural change will need to be implemented as an integrated and sequenced portfolio of responses if coastal C&amp;S are to contain the adverse risks of climate change ( ''high confidence'' ). The effectiveness and feasibility of any intervention—at any given moment—to reduce a particular climate-compounded coastal hazard risk or combination of risks depend upon the settlement archetype, including its geomorphological, cultural, economic, technical, institutional and political features, as well as on its historical development trajectory. Coastal C&amp;S will benefit from developing flexible adaptation pathways—sequences of adaptation strategies and intervention options—to navigate a dynamic solution space that changes in response to climate and other drivers of change, and is also shaped by human development choices and socioeconomic, technological and institutional change.

There is no silver bullet or panacea. But developing locally appropriate yet flexible pathways for CRD will help coastal communities to address escalating risks and uncertainty (Cross-Chapter Box DEEP in Chapter 17). Effective pathways are based on robust integrated information about dynamic coastal hazard risk and plausible interventions. However, their successful implementation requires multi-scale governance arrangements and practices able to bridge different administrative and sectoral capacities in the coastal zone; effective and accountable leadership; and inclusive decision-making arrangements to enable participation, manage conflicts and trade-offs, engender local ownership, and promote equity and justice in coastal adaptation plans and policies. Further, the feasibility of adaptation strategies and interventions, especially those entailing changing behaviours and practices, is increased by recognising and incorporating peoples’ values and beliefs and Indigenous and local knowledge systems, as well as the voices of women and vulnerable groups.

Coastal C&amp;S are on the frontline of observed climate change impacts and future risk ( ''high confidence'' ). Difficult choices will be made as climate- and ocean-driven extremes become more frequent. In the next few decades, many coastal regions and C&amp;S will have the opportunity to take actions to avoid and reduce risk, through incremental as well as more transformative interventions. Under higher levels of global warming, decisions will need to be made faster or respond to higher levels of SLR ( ''high confidence'' ; Cross-Chapter Box SLR in Chapter 3). This is particularly challenging in coastal C&amp;S characterised by the inertia and path dependency of development choices, with long lead times for adaptation planning and implementation, and the long design life and societal impact of many interventions. Given the risks assessed in coastal C&amp;S, the scale of climate impacts globally will depend to a large extent on whether coastal settlements develop and implement pre-emptive and flexible adaptation pathways, and whether a significant and timely reduction in greenhouse gas emissions is achieved in C&amp;S and globally ''(high confidence).''

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