Strong climate mitigation potential of rewetting oil palm plantations on tropical peatlands

• Published in: The Science of the total environment Vol. 952; p. 175829
• Main Authors: Novita, Nisa, Asyhari, Adibtya, Ritonga, Rasis P., Gangga, Adi, Anshari, Gusti Z., Jupesta, Joni, Bowen, Jennifer C., Lestari, Nurul Silva, Kauffman, J. Boone, Hoyt, Alison M., Perryman, Clarice R., Albar, Israr, Putra, Chandra Agung Septiadi, Adinugroho, Wahyu Catur, Winarno, Bondan, Castro, Miguel, Yeo, Samantha, Budiarna, Tryan, Yuono, Eko, Sianipar, Velyn C.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.11.2024
• Subjects: Climate change mitigation; Greenhouse gas emission; Natural climate solutions; Peatland; Peatland restoration; Rewetting; Greenhouse gas emission; Peatland restoration; Rewetting; Climate change mitigation; Natural climate solutions; Peatland
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.175829

For decades, tropical peatlands in Indonesia have been deforested and converted to other land uses, mainly oil palm plantations which now cover one-fourth of the degraded peatland area. Given that the capacity for peatland ecosystems to store carbon depends largely on hydrology, there is a growing interest in rewetting degraded peatlands to shift them back to a carbon sink. Recent estimates suggest that peatland rewetting may contribute up to 13 % of Indonesia's total mitigation potential from natural climate solutions. In this study, we measured CO2 and CH4 fluxes, soil temperature, and water table level (WTL) for drained oil palm plantations, rewetted oil palm plantations, and secondary forests located in the Mempawah and Kubu Raya Regencies of West Kalimantan, Indonesia. We found that peatland rewetting significantly reduced peat CO2 emissions, though CH4 uptake was not significantly different in rewetted peatland compared to drained peatland. Rewetting drained peatlands on oil palm plantations reduced heterotrophic respiration by 34 % and total respiration by 20 %. Our results suggest that rewetting drained oil palm plantations will not achieve low CO2 emissions as observed in secondary forests due to differences in vegetation or land management. However, extrapolating our results to the areas of degraded oil palm plantations in West Kalimantan suggests that successful peatland rewetting could still reduce emissions by 3.9 MtCO2 yr−1. This result confirms that rewetting oil palm plantations in tropical peatlands is an effective natural climate solution for achieving national emission reduction targets. [Display omitted] •Peatland rewetting significantly lowered CO2 fluxes with no clear shifts in CH4.•Rewetting in oil palm plantations reduced heterotrophic respiration by 34 %.•Rewetting in oil palm plantations reduced total soil respiration by 20 %.•In our case, rewetting will not reach the reference CO2 emissions in the forest.•New country-level emission factors for rewetting can be improved from this study.