Active afforestation of drained peatlands is not a viable option under the EU Nature Restoration Law.

The EU Nature Restoration Law (NRL) is critical for the restoration of degraded ecosystems and active afforestation of degraded peatlands has been suggested as a restoration measure under the NRL. Here, we discuss the current state of scientific evidence on the climate mitigation effects of peatlands under forestry. Afforestation of drained peatlands without restoring their hydrology does not fully restore ecosystem functions.

Full-cycle greenhouse gas balance of a Sphagnum paludiculture site on former bog grassland in Germany.

Growing Sphagnum on rewetted bogs (=Sphagnum paludiculture) is an alternative to drainage-based land use because it retains its value as productive land while mitigating greenhouse gas (GHG) emissions. However, studies on GHG exchange covering the full production system and cycle are missing. Here, we combined data of the establishment phase with newly recorded data of a 7-year old Sphagnum paludiculture site in Germany including partial Sphagnum harvest.

Prompt rewetting of drained peatlands reduces climate warming despite methane emissions.

Peatlands are strategic areas for climate change mitigation because of their matchless carbon stocks. Drained peatlands release this carbon to the atmosphere as carbon dioxide (CO). Peatland rewetting effectively stops these CO emissions, but also re-establishes the emission of methane (CH).

Topsoil removal reduced in-situ methane emissions in a temperate rewetted bog grassland by a hundredfold.

Peatland restoration is seen as an effective contribution to help achieve the aims of the Paris Agreement because currently huge amounts of peatlands in Northern Central Europe are under unsustainable drainage-based land use. If net zero greenhouse gas emissions from peatlands shall be reached by 2050, restoration measures have to be done as soon as possible. However, rewetting drained peatlands that were under intensive grassland use frequently results in high methane (CH) emissions, which is often seen as a counter-argument against rewetting.

Opaque closed chambers underestimate methane fluxes of Phragmites australis (Cav.) Trin. ex Steud.

Closed chamber measurements for methane emission estimation are often carried out with opaque chambers to avoid heating of the headspace. However, mainly in wetlands, some plants possess an internal convective gas transport which quickly responds to changes in irradiation. These plants have also been found to often channel a large part of the released methane in temperate fens.