Search

Canada's boreal forests and tundra ecosystems are responding to unprecedented climate change with implications for the global carbon (C) cycle and global climate. However, our ability to model the response of Canada's terrestrial ecosystems to climate change is limited and there has been no comprehensive, process‐based assessment of Canada's terrestrial C cycle. We tailor the Canadian Land Surface Scheme Including Biogeochemical Cycles (CLASSIC) to Canada and evaluate its C cycling performance against independent reference data. We utilize skill scores to assess model performance against reference data alongside benchmark scores that quantify the level of agreement between the reference data sets to aid in interpretation. Our results demonstrate CLASSIC's sensitivity to prescribed vegetation cover. They also show that the addition of five region‐specific Plant functional types (PFTs) improves CLASSIC's skill at simulating the Canadian C cycle. CLASSIC performs well when tailored to Canada, falls within the range of the reference data sets, and meets or exceeds the benchmark scores for most C cycling processes. New region‐specific land cover products, well‐informed PFT parameterizations, and more detailed reference data sets will facilitate improvements to the representation of the terrestrial C cycle in regional and global land surface models. Incorporating a parameterization for boreal disturbance processes and explicitly representing peatlands and permafrost soils will improve CLASSIC's future performance in Canada and other boreal regions. This is an important step toward a comprehensive process‐based assessment of Canada's terrestrial C cycle and evaluating Canada's net C balance under climate change. Plain Language Summary: Canada plays an important role in the global carbon cycle. Its boreal forests and tundra are responding to climate change. There has not been a comprehensive modeling assessment of Canada's land carbon cycle. We modify our model to better represent the distribution of plants in Canada and to include five new plant‐type representations. We then compare results from our model and other independent observation‐based data sets. Our modifications produced model results that agreed better with the independent data sets. This is an important step toward a comprehensive modeling assessment of Canada's land carbon cycle. Key Points: Using region‐specific prescribed vegetation cover and adding five region‐specific Plant functional types reduced model biases against reference dataCanadian Land Surface Scheme Including Biogeochemical Cycle's performance when tailored to the Canada domain is similar to that for comparisons between independent reference data setsFuture work should focus on boreal disturbance (i.e., fire, insect damage, and harvest), peatlands, and permafrost in Canada and other boreal regions [ABSTRACT FROM AUTHOR]