Evaluating physical and biogeochemical climate effects of boreal forests with EC-Earth

Boreal forests are particularly important for carbon storage. A warmer climate, combined with the expansion of these forests, is expected to enhance their role as carbon sinks in the future. Deforestation, where forests are replaced by crops and pastures, strongly affects land surface albedo and transpiration, leading to substantial carbon emissions into the atmosphere—a key driver of climate change.

In this study, we investigate the impacts of boreal forests on future climate using EC-Earth with full carbon cycle and prescribed CO₂ concentration. EC-Earth-Veg captures the physical effect mechanisms, while EC-Earth-CC incorporates both physical and biogeochemical effect. The biogeochemical effect can be isolated and quantified from these results.

Globally, the temperature responses to deforestation due to physical and biogeochemical effects largely cancel each other, but locally, deforestation has a large (more than 1°C in annual mean) impact on annual temperatures over deforested regions, accompanied with a marked expansion of Arctic sea ice.