Spatial Modeling of Canadian Boreal Peatland Carbon Sinks : An Integrative Framework to Support Climate and Development Policy

Abstract

Abstract

Peatlands are among the most effective carbon sinks, yet their stability is increasingly threatened by expanding land use and infrastructure. Spatially explicit information remains limited on where Canada’s boreal peatlands combine high CO₂ sink capacity with low human pressure. We mapped growing-season CO₂ sink potential across boreal peatlands and identified candidate conservation areas with strong CO₂ uptake and low human disturbance using widely available climate data. We used AmeriFlux eddy-covariance data from four Canadian boreal peatland flux-tower sites (2007–2019) to model climatic controls on net ecosystem exchange (NEE) of CO₂ and upscale predictions with ERA5-Land reanalysis data. A pooled multiple linear regression using air temperature, subsurface soil temperature (28–100 cm), and incoming shortwave radiation explained 57% of NEE variability (adjusted R²=0.57; RMSE=0.36 μmol CO₂ m⁻² s⁻¹). Comparisons of tower-measured and ERA5-Land climatic variables showed strong agreement for shortwave radiation and modest temperature biases, highlighting uncertainty in regional upscaling. Applying the fitted model across boreal peatlands predicted the strongest sinks in the Northwest Territories and weaker sinks toward the northern boreal margin and mountainous regions. We derived Predicted Carbon Sink Strength (PCSS) by weighting predicted NEE by peatland fractional cover and setting CO₂ sources to zero to emphasize strong sink potential in areas with high peatland cover. Finally, we combined PCSS with an inverted Human Footprint (IHFP) layer to construct a Boreal Peatland Conservation Index (BPCI) that supports conservation prioritization by highlighting low-disturbance areas with high predicted sink strength. High-scoring regions were concentrated in the Hudson Bay Lowlands and the Northwest Territories. Because predictions are based on four flux-tower sites and represent growing-season CO₂ exchange, results are best interpreted as screening-level guidance. Overall, this integrative framework provides an interpretable, updatable approach to identify boreal peatland regions where protecting CO₂ sinks may deliver high climate benefits with low development conflict.