NbS Triple Win Toolkit: Economics and Finance 73 Mangrove restoration Description of intervention Mangrove forests are under threat from unregulated harvesting(for firewood) and deforestation (to enable coastal developmentand aquaculture)94. Applying the intervention of mangrove restoration involves the regeneration of mangrove forest ecosystems in areas where they have previously existed but have since been degradedand/or removed entirely95. Monetised benefits Increased sustainability and provision of timber and forest products Supports local tourism Supports local fisheries through providing habitats for a varietyof commercially important fish species Carbon sequestration, storage or carbon markets Provides coastal protection and shoreline stabilisation bydecreasing the exposure to storms and flooding. Benefit-cost ratios and cost effectiveness evidence Generally, the evidence for cost-effectiveness of mangrove restoration is strong, with benefit-cost ratios reaching as high as 160. As with EbA, typically higher benefit-cost ratios are associated with either GHG emissions avoided and the associated social cost of carbon, oravoided losses from coastal assets. Often economic analysesinclude increased incomes from activities within the ecosystem,for example aquaculture or tourism. Mangroves provide a widerange of local co-benefits for biodiversity, soil health and waterquality69 which are not typically monetised98. Several other studies have also sought to quantify the wider impacts of mangrove forests and coral reefs across the globe. The global benefits of mangroves may be as high as $65 billion (USD) per annum, with 15 million people affected if mangroves were lost to alternative land uses since large numbers of the population live on the coast99. The exact benefits derived from mangroves varies across the world due to differences in flooding characteristics, ecosystem extent and the degree of exposure of coastlines to natural hazards100. Countries which have the highest value of economic assets protected by mangroves (USA, China, Mexico) are very disparate from those countries where the greatest number of the populace are protected (Viet Nam, Bangladesh, India), where the greatest proportion of GDP is protected (Belize, Suriname, Mozambique), or where the population is most vulnerable (Guinea, Mozambique, Sierra Leone and Madagascar)100. Non-monetised benefits Supports climate regulation Increased food and water security Spiritual and cultural benefits Supports water quality maintenance Further discussion Like many NbS interventions and projects which operate across the timespan of multiple decades, coastal NbS projects are sensitive to uncertainties and the assumptions driving economic and ecological analysis (i.e., the growth rate and survival of seedlings)101. These assumptions impact both the extent and quality of protection which mangroves provide coastal populations and assets in the short- and long-term. Net benefits may only arise after several years in thecase of restoration, although this is common amongst NbS