Nature Communications (Feb 2024)

Process-evaluation of forest aerosol-cloud-climate feedback shows clear evidence from observations and large uncertainty in models

  • Sara M. Blichner,
  • Taina Yli-Juuti,
  • Tero Mielonen,
  • Christopher Pöhlker,
  • Eemeli Holopainen,
  • Liine Heikkinen,
  • Claudia Mohr,
  • Paulo Artaxo,
  • Samara Carbone,
  • Bruno Backes Meller,
  • Cléo Quaresma Dias-Júnior,
  • Markku Kulmala,
  • Tuukka Petäjä,
  • Catherine E. Scott,
  • Carl Svenhag,
  • Lars Nieradzik,
  • Moa Sporre,
  • Daniel G. Partridge,
  • Emanuele Tovazzi,
  • Annele Virtanen,
  • Harri Kokkola,
  • Ilona Riipinen

DOI
https://doi.org/10.1038/s41467-024-45001-y
Journal volume & issue
Vol. 15, no. 1
pp. 1 – 12

Abstract

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Abstract Natural aerosol feedbacks are expected to become more important in the future, as anthropogenic aerosol emissions decrease due to air quality policy. One such feedback is initiated by the increase in biogenic volatile organic compound (BVOC) emissions with higher temperatures, leading to higher secondary organic aerosol (SOA) production and a cooling of the surface via impacts on cloud radiative properties. Motivated by the considerable spread in feedback strength in Earth System Models (ESMs), we here use two long-term observational datasets from boreal and tropical forests, together with satellite data, for a process-based evaluation of the BVOC-aerosol-cloud feedback in four ESMs. The model evaluation shows that the weakest modelled feedback estimates can likely be excluded, but highlights compensating errors making it difficult to draw conclusions of the strongest estimates. Overall, the method of evaluating along process chains shows promise in pin-pointing sources of uncertainty and constraining modelled aerosol feedbacks.