Co-benefits reveal the true value of blue ecosystems

<h2>Summary</h2> Blue carbon ecosystems provide a nature-based solution to climate change due to high rates of carbon sequestration. Green finance mechanisms are crucial tools to enable the conservation and restoration of these ecosystems. Only considering carbon provides an incomplete argument for investment, and the case for blue carbon ecosystems can be greatly improved by including multiple co-benefits (e.g., pollutant breakdown). A rapid evidence assessment of the monetary value of blue carbon ecosystems' co-benefits was undertaken. The inclusion of co-benefits resulted in the monetary value of saltmarsh increasing by an order of magnitude, the value of seagrass increasing 50 times, and the value of oyster beds and kelp increasing by more than two orders of magnitude. The inclusion of co-benefits significantly increases the overall value and has significant potential to influence financing of blue carbon ecosystems. The findings highlight key data gaps and six key recommendations for future research.