Global carbon stocks and potential emissions due to mangrove deforestation from 2000 to 2012

Mangrove forests store high densities of organic carbon compared to other forested ecosystems. High carbon storage coupled with high rates of deforestation means that mangroves contribute substantially to carbon emissions. Thus, mangroves are candidates for inclusion in Intended Nationally Determined Contributions (INDCs) to the UNFCC Payments for Ecosystem Services (PES) program. This study quantifies two datasets required for INDCs and PES reporting. These are annual mangrove carbon stocks from 2000 to 2012 at the global, national, and sub-national levels and global carbon emissions resulting from deforestation. Mangroves stored 4.19 Pg of carbon in 2012, with Indonesia, Brazil, Malaysia, and Papua New Guinea accounting for greater than 50% of this stock. 2.96 Pg of the global carbon stock is contained within the soil and 1.23 Pg in the living biomass. Two percent of global mangrove carbon was lost between 2000 and 2012, equivalent to a maximum potential of 316,996,250 t of CO2 emissions.

💡 Research Summary

The paper provides a comprehensive quantification of global mangrove carbon stocks and the emissions resulting from mangrove deforestation over the period 2000‑2012, with the aim of supplying the two key datasets required for reporting under the United Nations Framework Convention on Climate Change (UNFCCC) Intended Nationally Determined Contributions (INDCs) and Payments for Ecosystem Services (PES) schemes. Using a combination of satellite‑derived mangrove extent maps and published carbon density values, the authors calculate annual carbon inventories at global, national, and sub‑national scales. Carbon is partitioned into living biomass (average 30 t C ha⁻¹) and soil organic carbon (average 150 t C ha⁻¹ for the top 0‑1 m). In 2012, mangroves stored a total of 4.19 petagrams (Pg) of carbon, of which 2.96 Pg resides in soils and 1.23 Pg in living biomass. Indonesia, Brazil, Malaysia, and Papua New Guinea together account for more than half of this stock, with Indonesia alone contributing roughly 27 % (1.12 Pg).

Deforestation is quantified by comparing yearly mangrove area maps, revealing a cumulative loss of about 2 % of global mangrove area between 2000 and 2012 (≈0.17 % per year). The authors translate area loss into carbon loss by multiplying the lost area by the appropriate carbon density for each country. To estimate potential emissions, they adopt a conservative “complete combustion” scenario, assuming that all carbon removed from the ecosystem is instantly released as CO₂. Under this assumption, the maximum potential emissions amount to 3.17 × 10⁸ t CO₂ (≈317 Mt CO₂) over the 13‑year period. Indonesia is responsible for roughly 40 % of these emissions, driven primarily by rapid conversion of mangrove forests to aquaculture and agriculture in the Açuá and western Sumatra regions. Brazil and Malaysia contribute about 15 % and 12 % respectively.

The study underscores several critical insights. First, mangrove soils dominate the carbon pool, storing more than 70 % of total mangrove carbon, which highlights the importance of protecting deep soil carbon and incorporating soil‑focused restoration measures into climate mitigation strategies. Second, the spatial concentration of both carbon stocks and emissions in a few countries suggests that targeted national policies could yield disproportionate climate benefits. Third, the authors argue that the quantified stocks and emissions provide a robust scientific basis for including mangroves in INDCs and for designing PES mechanisms that reward both forest preservation and soil carbon retention.

Limitations are acknowledged. The use of average carbon density values may mask significant regional heterogeneity; only the top meter of soil is considered, potentially underestimating deeper carbon reservoirs; and the assumption of immediate, complete carbon release likely overstates short‑term emissions while ignoring slower decomposition pathways of residual biomass and soil organic matter. The authors call for future work that integrates high‑resolution field measurements, long‑term soil carbon monitoring, and dynamic modeling of carbon fluxes during and after mangrove restoration.

In conclusion, the paper delivers a data‑rich, methodologically transparent assessment of mangrove carbon dynamics, demonstrating that mangrove deforestation has already contributed a measurable share of global CO₂ emissions. By quantifying both the existing carbon stock and the emissions potential from loss, the study equips policymakers with the evidence needed to prioritize mangrove conservation and restoration within national climate commitments and ecosystem service payment frameworks.