Mangroves are an important ecosystem that provides valuable social, economic, and environmental services. Indonesia has placed mangroves on its national priority agenda in an important effort to sustainably manage this ecosystem and achieve national climate commitments. However, mangrove management is faced with complex challenges encompassing social, ecological, and economic issues. In order to achieve the government’s commitments and targets regarding mangrove restoration and conservation, an in-depth study on and critical review of mangrove management in Indonesia was conducted herein. This work aimed to provide a comprehensive analysis of the challenges and strategic recommendations for sustainable mangrove management in Indonesia. SWOT analysis was carried out to understand the strengths, weaknesses, opportunities, and threats related to mangrove management in Indonesia. To address these gaps, we reviewed the existing policies, current rehabilitation practices, environmental challenges, and research and technology implementations in the field. We found that strategies on mangrove ecosystem protection, such as improving the function and value of mangrove forests, integrating mangrove ecosystem management, strengthening political commitments and law enforcement, involving all stakeholders (especially coastal communities), and advancing research and innovations, are crucial for sustainable mangrove management and to support the national blue carbon agenda.

Southeast Asia (SEA) contributes approximately one-third of global land-use change carbon emissions, a substantial yet highly uncertain part of which is from anthropogenically-modified peat swamp forests (PSFs) and mangroves. Here, we report that between 2001–2022 land-use change impacting PSFs and mangroves in SEA generate approximately 691.8±97.2 teragrams of CO₂ equivalent emissions annually (TgCO₂eyr⁻¹) or 48% of region’s land-use change emissions, and carbon removal through secondary regrowth of −16.3 ± 2.0 TgCO₂eyr⁻¹. Indonesia (73%), Malaysia (14%), Myanmar (7%), and Vietnam (2%) combined accounted for over 90% of regional emissions from these sources. Consequently, great potential exists for emissions reduction through PSFs and mangroves conservation. Moreover, restoring degraded PSFs and mangroves could provide an additional annual mitigation potential of 94.4 ± 7.4 TgCO₂eyr⁻¹. Although peatlands and mangroves occupy only 5.4% of SEA land area, restoring and protecting these carbon-dense ecosystems can contribute substantially to climate change mitigation, while maintaining valuable ecosystem services, livelihoods and biodiversity.

Indonesia offers a dramatic opportunity to contribute to tackling climate change by deploying natural climate solutions (NCS), increasing carbon sequestration and storage through the protection, improved management, and restoration of drylands, peatlands, and mangrove ecosystems. Here, we estimate Indonesia’s NCS mitigation opportunity for the first time using national datasets. We calculated the maximum NCS mitigation potential extent using datasets of annual national land cover, peat soil, and critical lands. We collated a national emissions factor database for each pathway, calculated from a meta-analysis, recent publications from our team, and available literature. The maximum NCS mitigation potential in 2030 is 1.3 ± 0.04 GtCO₂e yr⁻¹, based on the historical baseline period from 2009–2019. This maximum NCS potential is double Indonesia’s nationally determined contribution (NDC) target from the forestry and other land use sector. Of this potential opportunity, 77% comes from wetland ecosystems. Peatlands have the largest NCS mitigation potential (960 ± 15.4 MtCO₂e yr⁻¹ or 71.5 MgCO₂e ha⁻¹ yr⁻¹) among all other ecosystems. Mangroves provide a smaller total potential (41.1 ± 1.4 MtCO₂e yr⁻¹) but have a much higher mitigation density (12.2 MgCO₂e ha⁻¹ yr⁻¹) compared to dryland ecosystems (2.9 MgCO₂e ha⁻¹ yr⁻¹). Therefore, protecting, managing, and restoring Indonesia’s wetlands is key to achieving the country’s emissions reduction target by 2030. The results of this study can be used to inform conservation programs and national climate policy to prioritize wetlands and other land sector initiatives to fulfill Indonesia’s NDC by 2030, while simultaneously providing additional co-benefits and contributing to COVID-19 recovery and economic sustainability.

Reforestation in the tropics is highlighted as an important intervention to mitigate climate change globally because of its potential for high CO₂ removal rates, ranging from 4.5 to 40.7 t CO₂e ha⁻¹ yr⁻¹ during the first 20 years of tree growth. Reforestation is critical to meeting emissions’ targets of the Paris Climate Agreement, as well as achieving Indonesia’s Nationally Determined Contribution (NDC) targets. Increasing carbon stocks through forest and land rehabilitation activities (RHL) is one of the Ministry of Environment and Forestry (MoEF) five main strategies for reducing greenhouse gas (GHG) emissions from the land sector. This study focuses on reforestation opportunities to support Indonesia’s NDC in reducing GHG emissions by 2030. We identified unproductive areas of land (shrub, open land) with highly degraded conditions as potential areas for reforestation. Based on Indonesian data of land cover change, we found that reforestation activities during 2019–2030 (11 years) under a realistic, ambitious and very ambitious scenario may remove carbon up to −0.25 GtCO₂e (equal to −23 MtCO₂e yr⁻¹), −1.3 GtCO₂e (equal to −124 MtCO₂e yr⁻¹) and −2.7 GtCO₂e (equal to −247 MtCO₂e yr⁻¹), respectively. Based on international data of land cover change (Hansen et al. 2013), reforestation activities during 2019–2030, under a realistic, ambitious, and very ambitious scenario, have the opportunities to remove −17 MtCO₂e yr⁻¹, −118 MtCO₂e yr⁻¹, and −241 MtCO₂e yr⁻¹, respectively. This study demonstrates that ambitious and very ambitious scenarios of reforestation activities can significantly contribute to Indonesia’s forestry-related NDC in 2030 by reducing the Indonesia Business As Usual (BAU) emissions up to 17% and 35%.

Significant efforts have been invested to restore degraded peatlands in Indonesia considering the high mitigation potential as an effective natural climate solution. However, peat restoration in Indonesia faces challenges such as suboptimal planning and risk management. In this study, we assessed the national potential peat restoration area using spatial analysis and identified the associated risks based on lessons learned from past restoration efforts. We estimated the extent of potential restoration areas by analyzing canal networks, burnt areas, and critical land maps at the national scale. We conducted focus group discussions (FGD), in‐depth interviews, followed by a national workshop with relevant stakeholders to assess the potential risks and develop risk management strategies for peat restoration. Our analysis estimated 6 Mha, or 45% of Indonesia's total peatland area, as potentially restorable areas for rewetting and/or revegetation efforts. Of this potential area, 50% falls under concession holder management. The identified risks consisted of technical (39%), management (38%), social (17%), and economic (6%) factors, with 15 and 22% classified as extreme and high risk, respectively. Policymakers can use these findings to strengthen regulations and improve the chances of successful restoration implementation, supporting Indonesia's emissions reduction target and providing economic benefits for restoration actors.

Drainage is a major means of the conversion of tropical peat forests into agriculture. Accordingly, drained peat becomes a large source of carbon. However, the amount of carbon (C) loss from drained peats is not simply measured. The current C loss estimate is usually based on a single proxy of the groundwater table, spatially and temporarily dynamic. The relation between groundwater table and C emission is commonly not linear because of the complex natures of heterotrophic carbon emission. Peatland drainage or lowering groundwater table provides plenty of oxygen into the upper layer of peat above the water table, where microbial activity becomes active. Consequently, lowering the water table escalates subsidence that causes physical changes of organic matter (OM) and carbon emission due to microbial oxidation. This paper reviews peat bulk density (BD), total organic carbon (TOC) content, and subsidence rate of tropical peat forest and drained peat. Data of BD, TOC, and subsidence were derived from published and unpublished sources. We found that BD is generally higher in the top surface layer in drained peat than in the undrained peat. TOC values in both drained and undrained are lower in the top and higher in the bottom layer. To estimate carbon emission from the top layer (0–50 cm) in drained peats, we use BD value 0.12 to 0.15 g cm⁻³, TOC value of 50%, and a 60% conservatively oxidative correction factor. The average peat subsidence is 3.9 cm yr⁻¹. The range of subsidence rate per year is between 2 and 6 cm, which results in estimated emission between 30 and 90 t CO₂e ha⁻¹ yr⁻¹. This estimate is comparable to those of other studies and Tier 1 emission factor of the 2013 IPCC GHG Inventory on Wetlands. We argue that subsidence is a practical approach to estimate carbon emission from drained tropical peat is more applicable than the use of groundwater table.