Editing IPCC:AR6/SROCC/Chapter-4 (section)

===== 4.4.2.3.5 Co-benefits and drawbacks of ecosystem-based adaptation =====

There is high confidence that ecosystem-based measures provide multiple co-benefits such as sequestering carbon (Siikamäki et al., 2012 <sup>[[#fn:r1721|1721]]</sup> ; Hamilton and Friess, 2018 <sup>[[#fn:r1722|1722]]</sup> ), income from tourism (Carr and Mendelsohn, 2003 <sup>[[#fn:r1723|1723]]</sup> ; Spalding et al., 2017 <sup>[[#fn:r1724|1724]]</sup> ), enhancing coastal fishery productivity (Carrasquilla-Henao and Juanes, 2017 <sup>[[#fn:r1725|1725]]</sup> ; Taylor et al., 2018 <sup>[[#fn:r1726|1726]]</sup> ), improving water quality (Coen et al., 2007 <sup>[[#fn:r1727|1727]]</sup> ; Lamb et al., 2017 <sup>[[#fn:r1728|1728]]</sup> ), providing raw material for food, medicine, fuel and construction (Hussain and Badola, 2010 <sup>[[#fn:r1729|1729]]</sup> ; Uddin et al., 2013 <sup>[[#fn:r1730|1730]]</sup> ), and a range of intangible and cultural benefits (Scyphers et al., 2015 <sup>[[#fn:r1731|1731]]</sup> ) that help improve the resilience of communities vulnerable to sea level hazards (Sutton-Grier et al., 2015 <sup>[[#fn:r1732|1732]]</sup> ).

In comparison to hard structures like seawalls, EbA measures, particularly coastal wetlands, require more land (The Royal Society Science Policy Centre, 2014), and competition for land is often why the ecosystems have declined in the first place (4.4.2.3.1). On developed coasts, this land is often not available. In such cases, hybrid measures that either combine EbA measures with structural measures like mangrove forests in front of dikes (Dasgupta et al., 2019 <sup>[[#fn:r1733|1733]]</sup> ), or build ecological enhancements into engineered structures can provide an effective solution. Like any other feature that interacts with coastal processes, natural wetlands and reefs can increase flooding in some instances, for example, due to the redistribution or acceleration of flows in channels within a wetland system (Marsooli et al., 2016 <sup>[[#fn:r1734|1734]]</sup> ), or an increase in infragravity wave (i.e., surface gravity waves with frequencies lower than wind waves) energy behind a reef (Roeber and Bricker, 2015 <sup>[[#fn:r1735|1735]]</sup> ).

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