Peat cutaway properties define after-use options and capacity for climate regulation.

Mitigating climate change and halting biodiversity loss require sustainable after-use strategies for peat extraction sites. This study evaluates the climate regulation potential of post-extraction land use using two peat cutaway sites in South Ostrobothnia, Finland, as case examples. The land use portfolio examined includes afforestation (conventional and short-rotation), peatland restoration, creation of open-water wetlands, conventional agriculture, reed canary grass cultivation and paludiculture. First, we mapped all suitable areas for each land use at the two case study sites, based on detailed spatial data on surface elevation, peat thickness and subsoil characteristics. Second, we calculated the climate warming impact of each land use based on published greenhouse gas flux and biomass estimates using REFUGE4, a climate impact model. Third, we assessed the climate impact of land-use scenarios aligned with five different objectives: climate regulation, ecological restoration, food production, timber production, and peat-replacing biomass production. This allowed us to explore how landowners' preferences or policy choices may influence climate outcomes. The results suggest that various climate-wise land use combinations are feasible after peat extraction, depending on site-specific conditions and landowner and policy preferences. We propose that tailoring land use to site characteristics and using strategic damming and ditching to create a multi-habitat landscape can provide both economic and ecological benefits. However, substantial knowledge gaps remain regarding greenhouse gas fluxes from post-extraction land uses.