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

Research output: Contribution to journalArticle

Abstract

Atmospheric aerosol particles influence the climate system directly by scattering and absorbing solar radiation, and indirectly by acting as cloud condensation nuclei(1-4). 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 gases(1). In the future, tightening of controls on anthropogenic aerosol and precursor vapour emissions to achieve higher air quality may weaken this beneficial effect(5-)7. Natural aerosols, too, might affect future warming(2,3,8,9). 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.

Details

Authors
  • Pauli Paasonen
  • Ari Asmi
  • Tuukka Petaja
  • Maija K. Kajos
  • Mikko Aijala
  • Heikki Junninen
  • Jonathan P. D. Abbatt
  • Almut Arneth
  • Wolfram Birmili
  • Hugo Denier van der Gon
  • Amar Hamed
  • Andras Hoffer
  • Lauri Laakso
  • Ari Laaksonen
  • W. Richard Leaitch
  • Christian Plass-Duelmer
  • Sara C. Pryor
  • Petri Raisanen
  • Alfred Wiedensohler
  • Douglas R. Worsnop
  • Veli-Matti Kerminen
  • Markku Kulmala
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Subatomic Physics
  • Physical Geography
Original languageEnglish
Pages (from-to)438-442
JournalNature Geoscience
Volume6
Issue number6
Publication statusPublished - 2013
Publication categoryResearch
Peer-reviewedYes

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Nuclear Physics (Faculty of Technology) (011013007), Dept of Physical Geography and Ecosystem Science (011010000)