Substantial large-scale feedbacks between natural aerosols and climate

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The terrestrial biosphere is an important source of natural aerosol. Natural aerosol sources alter climate, but are also strongly controlled by climate, leading to the potential for natural aerosol–climate feedbacks. Here we use a global aerosol model to make an assessment of terrestrial natural aerosol–climate feedbacks, constrained by observations of aerosol number. We find that warmer-than-average temperatures are associated with higher-than-average number concentrations of large (>100 nm diameter) particles, particularly during the summer. This relationship is well reproduced by the model and is driven by both meteorological variability and variability in natural aerosol from biogenic and landscape fire sources. We find that the calculated extratropical annual mean aerosol radiative effect (both direct and indirect) is negatively related to the observed global temperature anomaly, and is driven by a positive relationship between temperature and the emission of natural aerosol. The extratropical aerosol–climate feedback is estimated to be −0.14 W m−2 K−1 for landscape fire aerosol, greater than the −0.03 W m−2 K−1 estimated for biogenic secondary organic aerosol. These feedbacks are comparable in magnitude to other biogeochemical feedbacks, highlighting the need for natural aerosol feedbacks to be included in climate simulations.

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We acknowledge support from the Natural Environment Research Council (NE/K015966/1), EU Horizon 2020 (SC5-01-2014; grant agreement no 641816) and the Academy of Finland Centre of Excellence (grant nos 1118615 and 272041). We would like to thank the providers of measurement data for ref. 24. This work used the ARCHER UK National Supercomputing Service (

Author information


  1. Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, UK

    • C. E. Scott
    • , S. R. Arnold
    •  & D. V. Spracklen
  2. Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA

    • S. A. Monks
  3. Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA

    • S. A. Monks
  4. Department of Physics, University of Helsinki, Helsinki, Finland

    • A. Asmi
    •  & P. Paasonen
  5. International Institute for Applied Systems Analysis, Laxenburg, Austria

    • P. Paasonen


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All authors contributed to the research design. C.E.S. and S.A.M. performed model simulations. A.A. and P.P. provided observational data. C.E.S., D.V.S. and S.R.A. analysed the data. All authors contributed to scientific discussions and helped to write the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to C. E. Scott or D. V. Spracklen.

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