Beyond constitutive plant BVOCs: modelling emissions from litter, permafrost soil, forest management and stress disturbance

Earth system models have incrementally integrated the climate effects of biogenic volatile organic compounds (BVOCs). Currently, the global estimate stands at less than 1 PgC/year, considering only the emissions from actively growing plants while neglecting other sources of BVOCs and emissions from plants under stress.

Based on process understanding from various empirical data, this study extends beyond modelling plant BVOCs to include BVOC emissions from multiple ecosystem components, including litterfall, soil, forest management, and stress disturbance, into the dynamic vegetation model LPJ-GUESS. We will present four case studies in which these emissions are accounted for and compared with leaf constitutive emissions, highlighting their dynamic contributions to the ecosystem's total BVOC budget.

Furthermore, LPJ-GUESS previously simulated only isoprene and monoterpene emissions from plants, and this study further extends the model to consider all major BVOC compound groups (with a total of 150 compound species specified). We have dynamically coupled the LPJ-GUESS modelled BVOC emissions into the atmospheric chemistry and transport module TM5 within the European Earth System Model EC-Earth to assess the atmospheric impacts. We will also showcase the modelled impacts of BVOC emissions on atmospheric variables based on the coupled EC-Earth runs. The modelling framework provides an essential tool for integrating various ecosystem processes to understand BVOC emission dynamics and further assess the associated climate impact mechanically.