Warming-induced increase in aerosol number concentration likely to moderate climate change


Atmospheric aerosol particles influence the climate system directly by scattering and absorbing solar radiation, and indirectly by acting as cloud condensation nuclei1,2,3,4. Apart from black carbon aerosol, aerosols cause a negative radiative forcing at the top of the atmosphere and substantially mitigate the warming caused by greenhouse gases1. In the future, tightening of controls on anthropogenic aerosol and precursor vapour emissions to achieve higher air quality may weaken this beneficial effect5,6,7. Natural aerosols, too, might affect future warming2,3,8,9. Here we analyse long-term observations of concentrations and compositions of aerosol particles and their biogenic precursor vapours in continental mid- and high-latitude environments. We use measurements of particle number size distribution together with boundary layer heights derived from reanalysis data to show that the boundary layer burden of cloud condensation nuclei increases exponentially with temperature. Our results confirm a negative feedback mechanism between the continental biosphere, aerosols and climate: aerosol cooling effects are strengthened by rising biogenic organic vapour emissions in response to warming, which in turn enhance condensation on particles and their growth to the size of cloud condensation nuclei. This natural growth mechanism produces roughly 50% of particles at the size of cloud condensation nuclei across Europe. We conclude that biosphere–atmosphere interactions are crucial for aerosol climate effects and can significantly influence the effects of anthropogenic aerosol emission controls, both on climate and air quality.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Measurement locations and data periods.
Figure 2: The relationship between air temperature and the number concentration and burden of CCN-sized aerosol particles.
Figure 3: Concentration N100 as a function of gas phase monoterpene concentration ([MT]) and organic aerosol mass mOA (inset) at T>5 °C.
Figure 4: Schematic and estimated regional strengths of the proposed climate feedback mechanism.
Figure 5: Schematic summarizing the implications of the temperature dependence of CCN-sized particle burdens (B100).


  1. 1

    Forster, P. et al. in Climate Change 2007: The Physical Science Basis (eds Solomon, S. et al.) 129–234 (Cambridge Univ. Press, 2007).

    Google Scholar 

  2. 2

    Carslaw, K. S. et al. A review of natural aerosol interactions and feedbacks within the Earth system. Atmos. Chem. Phys. 10, 1701–1737 (2010).

    Article  Google Scholar 

  3. 3

    Arneth, A. et al. Terrestrial biogeochemical feedbacks in the climate system. Nature Geosci. 3, 525–532 (2010).

    Article  Google Scholar 

  4. 4

    Mahowald, N. Aerosol indirect effects on biogeochemical cycles and climate. Science 334, 794–796 (2011).

    Article  Google Scholar 

  5. 5

    Arneth, A., Unger, N., Kulmala, M. & Andreae, M. O. Clean the air, heat the planet. Science 326, 672–673 (2009).

    Article  Google Scholar 

  6. 6

    Mickley, L. J., Leibensperger, E. M., Jacob, D. J. & Rind, D. Regional warming from aerosol removal over the United States: Results from a transient 2010–2050 climate simulation. Atmos. Environ. 46, 545–553 (2012).

    Article  Google Scholar 

  7. 7

    Makkonen, R. et al. Air pollution control and decreasing new particle formation lead to strong climate warming. Atmos. Chem. Phys. 12, 1515–1524 (2012).

    Article  Google Scholar 

  8. 8

    Quinn, P. K. & Bates, T. S. The case against climate regulation via oceanic phytoplankton sulphur emissions. Nature 480, 51–56 (2011).

    Article  Google Scholar 

  9. 9

    Kulmala, M. et al. A new feedback mechanism linking forests, aerosols, and climate. Atmos. Chem. Phys. 4, 557–562 (2004).

    Article  Google Scholar 

  10. 10

    Guenther, A. B. et al. A global model for natural volatile organic compound emissions. J. Geophys. Res. 100, 8873–8892 (1995).

    Article  Google Scholar 

  11. 11

    Hallquist, M. et al. The formation, properties and impact of secondary organic aerosol: Current and emerging issues. Atmos. Chem. Phys. 9, 5155–5236 (2009).

    Article  Google Scholar 

  12. 12

    Jimenez, J. L. et al. Evolution of organic aerosols in the atmosphere. Science 326, 1525–1529 (2009).

    Article  Google Scholar 

  13. 13

    Leaitch, W. R. et al. Temperature response of the submicron organic aerosol from temperate forests. Atmos. Environ. 45, 6696–6704 (2011).

    Article  Google Scholar 

  14. 14

    Tunved, P. et al. High natural aerosol loading over boreal forests. Science 312, 261–263 (2006).

    Article  Google Scholar 

  15. 15

    Lee, A. K. Y. et al. Characterization of aerosol and cloud water at a mountain site during WACS 2010: Secondary organic aerosol formation through oxidative cloud processing. Atmos. Chem. Phys. 12, 7103–7116 (2012).

    Article  Google Scholar 

  16. 16

    Riipinen, I. et al. Organic condensation: A vital link connecting aerosol formation to cloud condensation nuclei (CCN) concentrations. Atmos. Chem. Phys. 11, 3865–3878 (2011).

    Article  Google Scholar 

  17. 17

    Riipinen, I. et al. The contribution of organics to atmospheric nanoparticle growth. Nature Geosci. 5, 453–458 (2012).

    Article  Google Scholar 

  18. 18

    Pierce, J. R. et al. Nucleation and condensational growth to CCN sizes during a sustained pristine biogenic SOA event in a forested mountain valley. Atmos. Chem. Phys. 12, 3147–3163 (2012).

    Article  Google Scholar 

  19. 19

    Dusek, U. et al. Size matters more than chemistry for cloud-nucleating ability of aerosol particles. Science 312, 1375–1378 (2006).

    Article  Google Scholar 

  20. 20

    Clarke, A & Kapustin, V. Hemispheric aerosol vertical profiles: Anthropogenic impacts on optical depth and cloud nuclei. Science 329, 1488–1492 (2010).

    Article  Google Scholar 

  21. 21

    Sihto, S-L. et al. Seasonal variation of CCN concentrations and aerosol activation properties in boreal forest. Atmos. Chem. Phys. 11, 13269–13285 (2011).

    Article  Google Scholar 

  22. 22

    Seidel, D. J. et al. Climatology of the planetary boundary layer over the continental United States and Europe. J. Geophys. Res. 117, D17106 (2012).

    Article  Google Scholar 

  23. 23

    Kulmala, M. et al. General overview: European integrated project on aerosol cloud climate and air quality interactions (EUCAARI)—integrating aerosol research from nano to global scales. Atmos. Chem. Phys. 11, 13061–13143 (2011).

    Article  Google Scholar 

  24. 24

    Barnaba, F., Angelini, F., Curci, G. & Gobbi, G. P. An important fingerprint of wildfires on the European aerosol load. Atmos. Chem. Phys. 11, 10487–10501 (2011).

    Article  Google Scholar 

  25. 25

    Després, V. R. et al. Primary biological aerosol particle in the atmosphere: A review. Tellus B 64, 015598 (2012).

    Article  Google Scholar 

  26. 26

    Day, M. C. & Pandis, S. N. Predicted changes in summertime organic aerosol concentrations due to increased temperatures. Atmos. Environ. 45, 6546–6556 (2011).

    Article  Google Scholar 

  27. 27

    Charlson, R. J., Lovelock, J. E., Andreae, M. O. & Warren, S. G. Oceanic phytoplankton, atmospheric sulphur, cloud albedo and climate. Nature 326, 655–661 (1987).

    Article  Google Scholar 

  28. 28

    Hansen, M. C., DeFries, R. S., Townshend, J. R. G. & Sohlberg, R. Global land cover classification at 1 km resolution using a decision tree classifier. Int. J. Remote Sens. 21, 1331–1365 (2000).

    Article  Google Scholar 

  29. 29

    Spracklen, D. V. et al. Aerosol mass spectrometer constraint on the global secondary organic aerosol budget. Atmos. Chem. Phys 11, 12109–12136 (2011).

    Article  Google Scholar 

  30. 30

    Stevens, B. & Feingold, G. Untangling aerosol effects on clouds and precipitation in a buffered system. Nature 461, 607–613 (2009).

    Article  Google Scholar 

Download references


This work was funded by European Research Council (ATMNUCLE, 227463), Academy of Finland (Center of Excellence Program project 1118615; projects 11750, 127210, 132640 and 139656), European Commission sixth Framework program (EUCAARI, contract no 036833-2; EUSAAR, contract no 026140), European Commission seventh Framework program (ACTRIS, contract no 262254; PEGASOS, contract no 265148), Maj and Tor Nessling Foundation (projects 2010143, 2011200, 2012443 and 2013325) and the Otto A. Malm foundation. For providing data, we acknowledge the Physical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado (for the boundary layer height data acquired from their web site at http://www.esrl.noaa.gov/psd/), the Hungarian Meteorological Service, Gerald Spindler, Pasi P. Aalto and Harald Flentje. We thank Ville Vakkari for help in quality assurance of Botsalano data and students and staff of North-West University (Mafikeng Campus), RSA, for weekly maintenance. The various measurements were supported by the German Federal Ministry for the Environment (FE 370343200), Environment Canada, NSERC, CFCAS-CAFC, the National Science Foundation (#0544745 and supplement, and 1102309), the Swedish Research Council (projects 2007-3745, 2007-4619 and 2010-4683) and the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (Formas, project 2009-615).

Author information




P.P. had the original idea; P.P. and A. Asmi made the data analysis; A. Asmi made the figures; M.K.K., T.H. and C.P-D. made the monoterpene concentration measurements and the data pre-analysis; M.Ä., H.J. and J.P.D.A. made the aerosol mass concentration measurements; A. Asmi, V-M.K., A.L. and P.R. made the calculations of the feedback strength; A. Arneth, W.B., A. Hamed, A. Hoffer, T.H., L.L., W.R.L., S.C.P., E.S., A.W. and T.P. provided the particle number size distribution and meteorological data; H.D.v.d.G. provided the anthropogenic emission inventory data; T.P., D.R.W. and M.K. supervised the analysis and writing; P.P., A. Asmi and V-M.K. wrote the paper; All authors contributed with their comments to the paper.

Corresponding authors

Correspondence to Pauli Paasonen or Ari Asmi.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 1298 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Paasonen, P., Asmi, A., Petäjä, T. et al. Warming-induced increase in aerosol number concentration likely to moderate climate change. Nature Geosci 6, 438–442 (2013). https://doi.org/10.1038/ngeo1800

Download citation

Further reading