Resilient coasts: optimising co-benefit solutions (Co-Opt)

海洋与社会的互动在沿海地区最为强烈，那里的社区既受益于海洋环境，也受到海洋环境的威胁。沿海洪水是2017年英国政府风险登记册上仅次于大流行性流感的第二大风险。仅在英格兰，就有超过180万户家庭面临沿海洪水和侵蚀的风险。极端事件已经对海岸产生了非常重大的影响，2013/14年冬季沿海洪水造成的损失超过5亿英镑，平均每年直接经济影响超过2.6亿英镑。在下一个世纪，主要由于不可避免的海平面上升，沿海灾害将不断增加。与此同时，英国承诺到2050年实现净零碳排放。因此，必须确保对英国海岸进行管理，使海岸保护能够适应未来的气候，并实现净零目标。通过在目前计划的所有地点维持硬“灰色”防御来保护海岸不太可能具有成本效益。因此，可持续的沿海管理和适应将需要更广泛的行动，并更多地使用与自然和谐相处、多功能、可带来额外效益的“绿色”解决方案。已有的例子包括有管理的重新调整、沿海生境恢复和大型沙地治理。然而，绿色解决方案的吸收仍然参差不齐。根据气候变化委员会的数据，有管理的调整的速度慢了五倍，无法实现2030年的目标。原因是复杂的，跨越整个人类-环境系统。基于自然的解决方案往往缺乏公众舆论的支持，并遭到社会抵制。尽管取消了对硬防御的长期承诺，但绿色方法的经济理由仍然不确定，原因是前期成本高，难以评估所提供的多种共同效益，以及未来环境和社会经济预测固有的不确定性。用于支持当今沿海管理和决策的框架（例如海岸线管理计划）没有提供解决这些问题的全面和一致的方法。其结果是，这些政策办法的效力降低。因此，实现英国海岸的可持续管理将需要新的框架，包括整个复杂的人类环境系统，并提供全面的科学基础，以确定不同的价值体系如何与决策相互作用，气候变化将如何影响沿海生态系统服务，以及决策支持工具如何结合联合收割机的多种不确定性。Co-Opt将提供一个新的集成和跨学科的系统-该框架将有效支持沿海和海岸线管理从硬“灰色”防御向软“绿色”解决方案的必要过渡。该框架将首次联合收割机结合复杂的沿海社会生态系统的概念表示，气候变化下的沿海生态系统服务的定量评估，以及社会观念和价值观如何影响前两个要素的特征。我们的新框架将在英国与国家、地区和地方利益相关者合作进行四个案例研究。这将提供一个可扩展和适应性强的解决方案，以支持沿海管理和政策制定。共同选择是与对实施和交付沿海和海岸线管理至关重要的项目伙伴（例如环境署、威尔士自然资源部、NatureScot、沿海团体）共同设计的，将满足他们的具体需求，包括在首选政策发生变化时，制定全面的成本效益分析和行动计划建议。Co-Opt将通过支持对复杂的沿海人类环境系统进行更综合和跨学科的表征，进一步造福于广泛的沿海科学基础。

Sea and society interact most strongly at the coast where communities both benefit from and are threatened by the marine environment. Coastal flooding was the second highest risk after pandemic flu on the UK government's risk register in 2017. Over 1.8 million homes are at risk of coastal flooding and erosion in England alone. Extreme events already have very significant impacts at the coast, with the damage due to coastal flooding during the winter 2013/14 in excess of £500 million, and direct economic impacts exceeding £260 million per year on average. Coastal hazards will be increasing over the next century primarily driven by unavoidable sea level rise. At the same time, the UK is committed to reach net zero carbon emissions by 2050. It is therefore essential to ensure that UK coasts are managed so that coastal protection is resilient to future climate and the net zero ambition is achieved. Protecting the coast by maintaining hard 'grey' defences in all locations currently planned is unlikely to be cost-effective. Sustainable coastal management and adaptation will therefore require a broader range of actions, and greater use of softer 'green' solutions that work with nature, are multifunctional, and can deliver additional benefits.Examples already exist and include managed realignment, restoration of coastal habitats, and sand mega-nourishments. However, the uptake of green solutions remains patchy. According to the Committee on Climate Change, the uptake of managed realignment is five times too slow to meet the stated 2030 target. Reasons are complex and span the whole human-environment system. Nature-based solutions often lack support from public opinion and meet social resistance. Despite removing long-term commitment to hard defences, the economic justification for green approaches remains uncertain due to high upfront costs, difficulty in valuing the multiple co-benefits offered, and uncertainties inherent to future environmental and socio-economic projections. The frameworks used to support present day coastal management and policy making (e.g. Shoreline Management Plans) do not provide comprehensive and consistent approaches to resolve these issues. Consequences are that the effectiveness of these policy approaches is reduced. Delivering sustainable management of UK coasts will therefore require new frameworks that embrace the whole complex human-environment system and provide thorough scientific underpinning to determine how different value systems interact with decision making, how climate change will impact coastal ecosystem services, and how decision support tools can combine multiple uncertainties.Co-Opt will deliver a new integrated and interdisciplinary system-based framework that will effectively support the required transition from hard 'grey' defences to softer 'green' solutions in coastal and shoreline management. This framework will combine for the first time a conceptual representation of the complex coastal socio-ecological system, quantitative valuation of coastal ecosystem services under a changing climate, and the characterisation of how social perceptions and values influence both previous elements. Our new framework will be demonstrated for four case studies in the UK in collaboration with national, regional, and local stakeholders. This will provide a scalable and adaptive solution to support coastal management and policy development. Co-Opt has been co-designed with project partners essential to the implementation and delivery of coastal and shoreline management (e.g. Environment Agency, Natural Resources Wales, NatureScot, coastal groups) and will address their specific needs including development of thorough cost-benefit analyses and recommendations for action plans when preferred policy changes. Co-Opt will further benefit the broad coastal science base by supporting more integrated and interdisciplinary characterisation of the complex coastal human-environment system.