Global and regional importance of the tropical peatland carbon pool

TLDR

Accurate inventory of tropical peatlands is essential to quantify their carbon pool, estimate peat‑derived greenhouse gas emissions from land‑use change, and inform carbon‑reduction policies. The authors reviewed published data on tropical peatland area and thickness and calculated peat volume and carbon content to provide best‑estimate ranges. They used these data to compute a tropical peatland area of 441,025 km² (≈11 % of global peatland), a volume of 1,758 Gm³ (≈18–25 % of global peat volume), and a carbon stock of 88.6 Gt (≈15–19 % of global peat carbon). Southeast Asia contains 56 % of the area, 77 % of the volume, and 77 % of the carbon, with Indonesia alone holding 57.4 Gt (65 %) of the tropical peat carbon.

Abstract

Abstract Accurate inventory of tropical peatland is important in order to (a) determine the magnitude of the carbon pool; (b) estimate the scale of transfers of peat‐derived greenhouse gases to the atmosphere resulting from land use change; and (c) support carbon emissions reduction policies. We review available information on tropical peatland area and thickness and calculate peat volume and carbon content in order to determine their best estimates and ranges of variation. Our best estimate of tropical peatland area is 441 025 km 2 (∼11% of global peatland area) of which 247 778 km 2 (56%) is in Southeast Asia. We estimate the volume of tropical peat to be 1758 Gm 3 (∼18–25% of global peat volume) with 1359 Gm 3 in Southeast Asia (77% of all tropical peat). This new assessment reveals a larger tropical peatland carbon pool than previous estimates, with a best estimate of 88.6 Gt (range 81.7–91.9 Gt) equal to 15–19% of the global peat carbon pool. Of this, 68.5 Gt (77%) is in Southeast Asia, equal to 11–14% of global peat carbon. A single country, Indonesia, has the largest share of tropical peat carbon (57.4 Gt, 65%), followed by Malaysia (9.1 Gt, 10%). These data are used to provide revised estimates for Indonesian and Malaysian forest soil carbon pools of 77 and 15 Gt, respectively, and total forest carbon pools (biomass plus soil) of 97 and 19 Gt. Peat carbon contributes 60% to the total forest soil carbon pool in Malaysia and 74% in Indonesia. These results emphasize the prominent global and regional roles played by the tropical peat carbon pool and the importance of including this pool in national and regional assessments of terrestrial carbon stocks and the prediction of peat‐derived greenhouse gas emissions.