A new feedback mechanism linking forests, aerosols, and climate

M. Kulmala (1) , T. Suni (1) , K. E. J. Lehtinen (1) , M. Dal Maso (1) , M. Boy (1) , A. Reissell (1, 2) , Ü. Rannik (1) , P. Aalto (1) , P. Keronen (1) , H. Hakola (2) , J. Bäck (1) , T. Hoffmann (3) , T. Vesala (1) , P. Hari (1)

1 Helsingin yliopisto = Helsingfors universitet = University of Helsinki
2 FMI - Finnish Meteorological Institute
3 Institute of Spectrochemistry and Applied Spectroscopy

The possible connections between the carbon balance of ecosystems and aerosol-cloud-climate interactions play a significant role in climate change studies. Carbon dioxide is a greenhouse gas, whereas the net effect of atmospheric aerosols is to cool the climate. Here, we investigated the connection between forest-atmosphere carbon exchange and aerosol dynamics in the continental boundary layer by means of multiannual data sets of particle formation and growth rates, of CO₂ fluxes, and of monoterpene concentrations in a Scots pine forest in southern Finland. We suggest a new, interesting link and a potentially important feedback among forest ecosystem functioning, aerosols, and climate: Considering that globally increasing temperatures and CO₂ fertilization are likely to lead to increased photosynthesis and forest growth, an increase in forest biomass would increase emissions of non-methane biogenic volatile organic compounds and thereby enhance organic aerosol production. This feedback mechanism couples the climate effect of CO₂ with that of aerosols in a novel way.

Domaines: Océan, Atmosphère

M. Kulmala, T. Suni, K. E. J. Lehtinen, M. Dal Maso, M. Boy, et al.. A new feedback mechanism linking forests, aerosols, and climate. Atmospheric Chemistry and Physics, 2004, 4 (2), pp.557-562. ⟨hal-00295416⟩