Implementation costs of restoring global mangrove forests

<h2>Summary</h2> Mangroves provide numerous ecosystem services and are increasingly recognized as a natural climate solution. As a result, multiple recent initiatives have set ambitious mangrove restoration targets. However, there has been little research estimating the costs of achieving such targets, either site by site or in aggregate. Here, we spatially model the costs of restoring mangroves globally based on reported implementation costs from 249 restoration projects in 25 countries. Using multiple regression analysis, we find that implementation costs decrease with project size, with project year, for aquaculture ponds, and in deltas and increase with national GDP per capita, for eroded sites, and on open coasts. Restoring mangroves across 1.10 million ha globally would remove 0.93 GtCO₂ at an implementation cost of $10.73 billion in 2022 international dollars (an average of $9,739 ha⁻¹ or $11.49 tCO₂⁻¹). Our global map of low-cost, high-impact sites can aid spatial prioritization of mangrove restoration and climate mitigation efforts.