Editing IPCC:AR6/WGII/Chapter-3 (section)

===== Solutions, trade-offs, residual risk, decisions and governance =====

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'''Humans are already adapting to climate-driven changes in marine systems, and while further adaptations are required even under low-emission scenarios (''' '''''high confidence''''' '''), transformative adaptation will be essential under high-emission scenarios (''' '''''high confidence''''' ''').''' Low-emission scenarios permit a wider array of feasible, effective and low-risk nature-based adaptation options (e.g., restoration, revegetation, conservation, early-warning systems for extreme events and public education) ( ''high confidence'' ). Under high-emission scenarios, adaptation options (e.g., hard infrastructure for coastal protection, assisted migration or evolution, livelihood diversification, migration and relocation of people) are more uncertain and require transformative governance changes ( ''high confidence'' ). Transformative climate adaptation will reinvent institutions to overcome obstacles arising from historical precedents, reducing current barriers to climate adaptation in cultural, financial and governance sectors ( ''high confidence'' ). Without transformation, global inequities will ''likely'' increase between regions ( ''high confidence'' ) and conflicts between jurisdictions may emerge and escalate. {3.5, 3.5.2, 3.5.5.3, 3.6, 3.6.2.1, 3.6.3.1, 3.6.3.2, 3.6.3.3, 3.6.4.1, 3.6.4.2, 3.6.5, Cross-Chapter Box SLR in Chapter 3, Cross-Chapter Box ILLNESS in Chapter 2}

'''Available adaptation options are unable to offset climate-change impacts on marine ecosystems and the services they provide (''' '''''high confidence''''' '''). Adaptation solutions implemented at appropriate scales, when combined with ambitious and urgent mitigation measures, can meaningfully reduce impacts (''' '''''high confidence''''' ''').''' Increasing evidence from implemented adaptations indicates that multi-level governance, early-warning systems for climate-associated marine hazards, seasonal and dynamic forecasts, habitat restoration, ecosystem-based management, climate-adaptive management and sustainable harvesting tend to be both feasible and effective ( ''high confidence'' ). Marine protected areas (MPAs), as currently implemented, do not confer resilience against warming and heatwaves ( ''medium confidence'' ) and are not expected to provide substantial protection against climate impacts past 2050 ( ''high confidence'' ). However, MPAs can contribute substantially to adaptation and mitigation if they are designed to address climate change, strategically implemented and well governed ( ''high confidence'' ). Habitat restoration limits climate-change-related loss of ecosystem services, including biodiversity, coastal protection, recreational use and tourism ( ''medium confidence'' ), provides mitigation benefits on local to regional scales (e.g., via carbon-storing ‘blue carbon’ ecosystems) ( ''high confidence'' ) and may safeguard fish-stock production in a warmer climate ( ''limited evidence'' ). Ambitious and swift global mitigation offers more adaptation options and pathways to sustain ecosystems and their services ( ''high confidence'' ). {3.4.2, 3.4.3.3, 3.5, 3.5.2, 3.5.3, 3.5.5.4, 3.5.5.5, 3.6.2.1, 3.6.2.2, 3.6.2.3, 3.6.3.1, 3.6.3.2, 3.6.3.3, 3.6.5, Figure 3.24, Figure 3.25}

'''Nature-based solutions for adaptation of ocean and coastal ecosystems can achieve multiple benefits when well designed and implemented (''' '''''high confidence''''' '''), but their effectiveness declines without ambitious and urgent mitigation (''' '''''high confidence''''' ''').''' Nature-based solutions, such as ecosystem-based management, climate-smart conservation approaches (i.e., climate-adaptive fisheries and conservation) and coastal habitat restoration, can be cost-effective and generate social, economic and cultural co-benefits while contributing to the conservation of marine biodiversity and reducing cumulative anthropogenic drivers ( ''high confidence'' ). The effectiveness of nature-based solutions declines with warming; conservation and restoration alone will be insufficient to protect coral reefs beyond 2030 ( ''high confidence'' ) and to protect mangroves beyond the 2040s ( ''high confidence'' ). The multidimensionality of climate-change impacts and their interactions with other anthropogenic stressors calls for integrated approaches that identify trade-offs and synergies across sectors and scales in space and time to build resilience of ocean and coastal ecosystems and the services they deliver ( ''high confidence'' ). {3.4.2, 3.5.2, 3.5.3, 3.5.5.3, 3.5.5.4, 3.5.5.5, 3.6.2.2, 3.6.3.2, 3.6.5, Figure 3.25, Table 3.SM.6}

'''Ocean-focused adaptations, especially those that employ nature-based solutions, address existing inequalities, and incorporate just and inclusive decision-making and implementation processes, support the UN Sustainable Development Goals (SDGs) (''' '''''high confidence''''' ''').''' There are predominantly positive synergies between adaptation options for Life Below Water (SDG14), Climate Action (SDG13) and social, economic and governance SDGs (SDG1–12, 16–17) ( ''high confidence'' ), but the ability of ocean adaptation to contribute to the SDGs is constrained by the degree of mitigation action ( ''high confidence'' ). Furthermore, existing inequalities and entrenched practices limit effective and just responses to climate change in coastal communities ( ''high confidence'' ). Momentum is growing towards transformative international and regional governance that will support comprehensive, equitable ocean and coastal adaptation while also achieving SDG14 ( ''robust evidence'' ), without compromising achievement of other SDGs. {3.6.4.0, 3.6.4.2, 3.6.4.3, Figure 3.26} .

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