Harnessing peatland rewetting for effective biochar-based carbon dioxide removal

Abstract

Biochar is widely recognised as a carbon dioxide removal (CDR) technology, but its stability depends on feedstock, pyrolysis conditions, and the soil environment. Current CDR schemes prioritise highly stable biochars to ensure long-term permanence, requiring high pyrolysis temperatures that reduce carbon yield and intensify competition for biomass. This perspective explores potential synergies between two distinct CDR approaches, biochar application and peatland rewetting, where rewetted peatlands could enhance biochar permanence by suppressing microbial decomposition, offering a means to improve both carbon retention and resource efficiency. Using decomposition rate modifiers from biogeochemical models, we estimate biochar stability in rewetted peat and assess its CDR efficiency relative to a counterfactual of high-stability biochar application to dry soils. This perspective suggests that rewetted peatlands significantly reduce biochar carbon losses, particularly for lower-stability biochars, making them more viable for long-term CDR. By allowing greater flexibility in biochar selection, this approach could improve the scalability of biochar deployment while alleviating biomass supply constraints. While challenges such as land-use transitions and methane emissions must be addressed, integrating biochar with peatland rewetting presents a high-impact strategy to optimise the efficiency of biomass-based CDR.

Keywords

CO₂ removal / Biochar stability / Negative emissions technology / Peatland restoration / Rewetting

Highlight

•	Rewetted peatlands significantly enhance biochar stability, particularly for less stable, higher-yield biochars.
•	Lower stability biochars in rewetted environments offer greater CO2 removal efficiency.
•	Integrating biochar with peatland rewetting creates synergistic climate mitigation benefits despite implementation challenges.

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Funding

Natural England(Paludiculture Exploration Fund)

Biotechnology and Biological Sciences Research Council(grant BB/V011561/1)

RIGHTS & PERMISSIONS

The Author(s)