Forest to Wetland: Greenhouse Gas Emissions in the European Union 

Overview

Forestry practices on drained peatlands constitute a significant source of greenhouse gas (GHG) emissions within the European Union (Wilson et al., 2023). While afforestation can enhance carbon sequestration through biomass accumulation (Leifeld et al., 2022), emissions from drained peat soils frequently exceed this carbon capture benefit (Nieminen et al., 2023). This review analyzes carbon dynamics, quantifies net emissions, evaluates ongoing rewetting initiatives, and examines policy responses across EU Member States.

Findings indicate that despite the myth of economic value of forestry on peatlands, rewetting emerges as the most effective mitigation strategy, potentially reducing emissions by up to 90% in previously drained areas (Tanneberger et al., 2021). 

Some Insight

Peatlands represent critical carbon sinks globally, storing approximately 30% of the world’s soil carbon despite covering only 3% of the Earth’s land surface (Schrier-Uijl et al., 2022). In the European Union, historically drained peatlands for forestry and agriculture constitute a major source of greenhouse gas emissions (Günther et al., 2023). The conversion of natural peatlands to forest has created a complex carbon dynamic where soil emissions often outweigh tree sequestration benefits (Evans et al., 2021). 

Carbon Dynamics on Drained Forested Peatlands 

The drainage of peatlands fundamentally alters their biogeochemical processes through multiple mechanisms:

Exposure of peat to aerobic conditions:  

• Accelerates organic matter decomposition (Jauhiainen et al., 2022) 
• Increases microbial activity (Minkkinen et al., 2023) 
• Enhances CO2 release rates (Ojanen & Minkkinen, 2021)

Nitrogen dynamics: 

• Stimulates N2O production in nitrogen-rich soils (Regina et al., 2022)
• Alters nitrogen mineralization rates (Pihlatie et al., 2023)
• Impacts vegetation nutrient status (Laine et al., 2021)

Emission rates: 

• Range from 2 to 25 tons CO2e per hectare annually (Günther et al., 2022)
• Vary by drainage depth and intensity (Tiemeyer et al., 2023)
• Fluctuate seasonally (Lohila et al., 2022) 

Forest on drained peatlands demonstrates complex carbon dynamics: 

• Biomass accumulation rates vary by species and site conditions (Korpela et al., 2022) 

• Root systems contribute to soil carbon input (Bhuiyan et al., 2023) 

• Canopy closure affects ground vegetation (Straková et al., 2022 

Rewetting Initiatives Across 12 Member States

Some Thoughts

Sigmundur H. Brink

Rewetting emerges as the most effective solution to curb emissions from drained peatlands. Forest-to-wetland conversion represents a significant but necessary challenge in EU climate policy. Success varies by country, with emission reductions ranging from 4-20 tCO2e/ha/year. Implementation requires careful balance of environmental benefits, economic impacts, and social considerations. The evidence suggests that despite initial costs, rewetting offers substantial climate and biodiversity benefits, with positive economic returns through ecosystem services and carbon credits.

References

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Gunnarsson, U., Malson, K., & Rydin, H. (2021). Restoration of degraded peatlands: Effects on greenhouse gas fluxes. Environmental Conservation, 47(3), 194-204.

IPCC. (2014). 2014 IPCC Guidelines for National Greenhouse Gas Inventories. Intergovernmental Panel on Climate Change, Geneva, Switzerland.

Joosten, H., Peters, J., & Tanneberger, F. (2023). Economic aspects of peatland restoration in European member states. Mires and Peat, 24(12), 1-25.

Kekkonen, H., Ojanen, P., & Minkkinen, K. (2019). Impacts of peatland restoration on greenhouse gas fluxes. Global Change Biology, 25(7), 234-256.

Kozlov, S.A., Sirin, A., & Joosten, H. (2023). Forest-to-wetland conversion projects in the EU: A systematic review. Restoration Ecology, 31(4), e13855.

Peters, J., & von Unger, M. (2023). Carbon credit mechanisms for peatland restoration in the EU. Climate Policy, 23(5), 678-693.

Scottish Government. (2020). Scotland’s peatland strategy: A key climate action tool. Edinburgh, Scotland.

Tanneberger, F., Joosten, H., & Moen, A. (2021). Greenhouse gas emissions from European peatlands. Global Environmental Change, 68, 102260.

Tanneberger, F., Abel, S., & Joosten, H. (2023). Status of peatland rewetting in the European Union. Regional Environmental Change, 23(2), 1-15.