Peatland restoration pathways to mitigate greenhouse gas emissions and retain peat carbon

Abstract

Peatlands play a crucial role in the global carbon (C) cycle, making their restoration a key strategy for mitigating greenhouse gas (GHG) emissions and retaining C. This study analyses the most common restoration pathways employed in boreal and temperate peatlands, potentially applicable in tropical peat swamp forests. Our analysis focuses on the GHG emissions and C retention potential of the restoration measures. To assess the C stock change in restored (rewetted) peatlands and afforested peatlands with continuous drainage, we adopt a conceptual approach that considers short-term C capture (GHG exchange between the atmosphere and the peatland ecosystem) and long-term C sequestration in peat. The primary criterion of our conceptual model is the capacity of restoration measures to capture C and reduce GHG emissions. Our findings indicate that carbon dioxide (CO2) is the most influential part of long-term climate impact of restored peatlands, whereas moderate methane (CH4) emissions and low N2O fluxes are relatively unimportant. However, lateral losses of dissolved and particulate C in water can account up to a half of the total C stock change. Among the restored peatland types, Sphagnum paludiculture showed the highest CO2 capture, followed by shallow lakes and reed/grass paludiculture. Shallow lakeshore vegetation in restored peatlands can reduce CO2 emissions and sequester C but still emit CH4, particularly during the first 20 years after restoration. Our conceptual modelling approach reveals that over a 300-year period, under stable climate conditions, drained bog forests can lose up to 50% of initial C content. In managed (regularly harvested) and continuously drained peatland forests, C accumulation in biomass and litter input does not compensate C losses from peat. In contrast, rewetted unmanaged peatland forests are turning into a persistent C sink. The modelling results emphasized the importance of long-term C balance analysis which considers soil C accumulation, moving beyond the short-term C cycling between vegetation and the atmosphere.

Pros and Cons of Strategies to Reduce Greenhouse Gas Emissions from Peatlands: Review of Possibilities

“…Similarly to peat rewetting, the plants used in paludiculture need a high water table that does not change throughout the year, contributing to CO 2 emission reduction [25]. Areas proper for paludiculture, mire, shallow lakes, or wet forests can be formed after the rewetting of peatlands [34].…”

“…The extensive drainage of peatlands for agricultural use, extraction as an energy source, and removal of all but a thin peat layer explain the decrease in peat quality [20,33]. It is predicted that in northern peatlands, GHG emissions from peatlands might increase in the following years because of global warming [34]. The European Union (EU) is rated as the third greatest carbon dioxide (CO 2 ) emitter of degraded peatlands after Russia and Indonesia [31], with annual GHG emissions of roughly 220 million megatons of CO 2 equivalents/year [35,36].…”

“…After the drainage, the peatland decomposes and releases carbon [50]. Peatland restoration promotes carbon sequestration and emissions of N 2 O reduction [34].…”

Perceptions of farmers regarding peatland restoration model of paludiculture in South Sumatra, Indonesia

“…To optimize the implementation of 3R strategy, one method proposed is paludiculture model. According to [20]- [23], the preservation of peatland with a rewetting strategy can be carried out using paludiculture model. Paludiculture, a cultivation approach in wetlands usually flooded with water [24] is carried out by improvising, innovating, and returning damaged peatland to the original state [25].…”

Editorial: Peatlands for climate change mitigation in agriculture

“…By reviewing the current literature and developing a conceptual model, the paper by Mander et al (2023) provides insights into the GHG emissions and C sequestration potential of different restoration options, such as paludiculture, shallow lakes, or restored peatlands in boreal, temperate, and tropical climates. Based on their assessment, Sphagnum paludiculture showed the highest C sequestration potential, followed by shallow lakes and reed/grass paludiculture.…”