title: Reduced anthropogenic aerosol radiative forcing caused by biogenic new particle formation.
abstract: The magnitude of aerosol radiative forcing caused by anthropogenic emissions depends on the baseline state of the atmosphere under pristine preindustrial conditions. Measurements show that particle formation in atmospheric conditions can occur solely from biogenic vapors. Here, we evaluate the potential effect of this source of particles on preindustrial cloud condensation nuclei (CCN) concentrations and aerosol-cloud radiative forcing over the industrial period. Model simulations show that the pure biogenic particle formation mechanism has a much larger relative effect on CCN concentrations in the preindustrial atmosphere than in the present atmosphere because of the lower aerosol concentrations. Consequently, preindustrial cloud albedo is increased more than under present day conditions, and therefore the cooling forcing of anthropogenic aerosols is reduced. The mechanism increases CCN concentrations by 20-100% over a large fraction of the preindustrial lower atmosphere, and the magnitude of annual global mean radiative forcing caused by changes of cloud albedo since 1750 is reduced by [Formula: see text] (27%) to [Formula: see text] Model uncertainties, relatively slow formation rates, and limited available ambient measurements make it difficult to establish the significance of a mechanism that has its dominant effect under preindustrial conditions. Our simulations predict more particle formation in the Amazon than is observed. However, the first observation of pure organic nucleation has now been reported for the free troposphere. Given the potentially significant effect on anthropogenic forcing, effort should be made to better understand such naturally driven aerosol processes.
authors: Department of Experimental Physics, CERN (European Organization for Nuclear Research), CH-1211 Geneva, Switzerland; hamish.gordon@cern.ch k.s.carslaw@leeds.ac.uk.
authors: Hamish
authors: 0000-0002-1822-3224
authors: H
authors: Gordon
authors: School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom.
authors: Kamalika
authors: K
authors: Sengupta
authors: School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom.
authors: Alexandru
authors: 0000-0002-2319-6769
authors: A
authors: Rap
authors: Helsinki Institute of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Jonathan
authors: J
authors: Duplissy
authors: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
authors: Carla
authors: C
authors: Frege
authors: Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany; Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, CO 80309; Chemical Sciences Division, National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory, Boulder, CO 80305.
authors: Christina
authors: C
authors: Williamson
authors: Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany.
authors: Martin
authors: M
authors: Heinritzi
authors: Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany.
authors: Mario
authors: M
authors: Simon
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Chao
authors: C
authors: Yan
authors: Department of Experimental Physics, CERN (European Organization for Nuclear Research), CH-1211 Geneva, Switzerland; Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany.
authors: João
authors: J
authors: Almeida
authors: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
authors: Jasmin
authors: J
authors: Tröstl
authors: Helsinki Institute of Physics, University of Helsinki, FI-00014 Helsinki, Finland; Department of Applied Physics, University of Eastern Finland, FI-70211 Kuopio, Finland.
authors: Tuomo
authors: T
authors: Nieminen
authors: Laboratoire de Physique des lasers, Atomes et Molcules Université Lille 1, UMR 8523 CNRS, 59655 Villeneuve d'Ascq, France.
authors: Ismael K
authors: IK
authors: Ortega
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Robert
authors: R
authors: Wagner
authors: School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom; Atmospheric Research Centre of Eastern Finland, Finnish Meteorological Institute, 70211 Kuopio, Finland.
authors: Eimear M
authors: EM
authors: Dunne
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Alexey
authors: A
authors: Adamov
authors: Laboratory for Systems, Instrumentation and Modeling in Science and Technology for Space and the Environment, University of Lisbon and University of Beira Interior, 1849-016 Lisbon, Portugal.
authors: Antonio
authors: A
authors: Amorim
authors: Institute for Ion and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria; Ionicon Analytik GmbH, 6020 Innsbruck, Austria.
authors: Anne-Kathrin
authors: AK
authors: Bernhammer
authors: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen, Switzerland; Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Federico
authors: F
authors: Bianchi
authors: Institute for Ion and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria.
authors: Martin
authors: M
authors: Breitenlechner
authors: Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany.
authors: Sophia
authors: S
authors: Brilke
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Xuemeng
authors: X
authors: Chen
authors: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125.
authors: Jill S
authors: JS
authors: Craven
authors: Department of Experimental Physics, CERN (European Organization for Nuclear Research), CH-1211 Geneva, Switzerland.
authors: Antonio
authors: A
authors: Dias
authors: Department of Experimental Physics, CERN (European Organization for Nuclear Research), CH-1211 Geneva, Switzerland; Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany.
authors: Sebastian
authors: S
authors: Ehrhart
authors: Institute for Ion and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria.
authors: Lukas
authors: L
authors: Fischer
authors: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125.
authors: Richard C
authors: RC
authors: Flagan
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Alessandro
authors: A
authors: Franchin
authors: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
authors: Claudia
authors: C
authors: Fuchs
authors: Department of Experimental Physics, CERN (European Organization for Nuclear Research), CH-1211 Geneva, Switzerland.
authors: Roberto
authors: R
authors: Guida
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Jani
authors: J
authors: Hakala
authors: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen, Switzerland; Schnee- und Lawinenforschung (SLF), Eidgenössische Forschungsanstalt für Wald, Schnee und Landschaft (WSL) Institute for Snow and Avalanche Research, CH-7260 Davos, Switzerland.
authors: Christopher R
authors: CR
authors: Hoyle
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Tuija
authors: T
authors: Jokinen
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Heikki
authors: H
authors: Junninen
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Juha
authors: J
authors: Kangasluoma
authors: Department of Applied Physics, University of Eastern Finland, FI-70211 Kuopio, Finland; Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, South Korea.
authors: Jaeseok
authors: J
authors: Kim
authors: Department of Experimental Physics, CERN (European Organization for Nuclear Research), CH-1211 Geneva, Switzerland; Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany.
authors: Jasper
authors: 0000-0003-2341-9069
authors: J
authors: Kirkby
authors: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
authors: Manuel
authors: M
authors: Krapf
authors: Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany.
authors: Andreas
authors: A
authors: Kürten
authors: Department of Applied Physics, University of Eastern Finland, FI-70211 Kuopio, Finland; Climate Change Research Unit, Finnish Meteorological Institute, FI-00101 Helsinki, Finland.
authors: Ari
authors: A
authors: Laaksonen
authors: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen, Switzerland; Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Katrianne
authors: K
authors: Lehtipalo
authors: Solar and Cosmic Ray Research Laboratory, Lebedev Physical Institute, 119991 Moscow, Russia.
authors: Vladimir
authors: V
authors: Makhmutov
authors: Department of Experimental Physics, CERN (European Organization for Nuclear Research), CH-1211 Geneva, Switzerland.
authors: Serge
authors: S
authors: Mathot
authors: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
authors: Ugo
authors: U
authors: Molteni
authors: Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, CO 80309; Chemical Sciences Division, National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory, Boulder, CO 80305.
authors: Sarah A
authors: SA
authors: Monks
authors: Department of Experimental Physics, CERN (European Organization for Nuclear Research), CH-1211 Geneva, Switzerland.
authors: Antti
authors: A
authors: Onnela
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Otso
authors: O
authors: Peräkylä
authors: Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany.
authors: Felix
authors: F
authors: Piel
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Tuukka
authors: T
authors: Petäjä
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Arnaud P
authors: AP
authors: Praplan
authors: School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom.
authors: Kirsty J
authors: KJ
authors: Pringle
authors: School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom; National Centre for Earth Observation, University of Leeds, LS2 9JT Leeds, United Kingdom.
authors: Nigel A D
authors: NA
authors: Richards
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Matti P
authors: MP
authors: Rissanen
authors: Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany.
authors: Linda
authors: L
authors: Rondo
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Nina
authors: N
authors: Sarnela
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Siegfried
authors: 0000-0002-5777-4897
authors: S
authors: Schobesberger
authors: School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom.
authors: Catherine E
authors: CE
authors: Scott
authors: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125.
authors: John H
authors: JH
authors: Seinfeld
authors: National Centre for Earth Observation, University of Leeds, LS2 9JT Leeds, United Kingdom.
authors: Sangeeta
authors: S
authors: Sharma
authors: Helsinki Institute of Physics, University of Helsinki, FI-00014 Helsinki, Finland; Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Mikko
authors: M
authors: Sipilä
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland; Institute for Ion and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria; Faculty of Physics, University of Vienna, 1090 Vienna, Austria.
authors: Gerhard
authors: G
authors: Steiner
authors: Solar and Cosmic Ray Research Laboratory, Lebedev Physical Institute, 119991 Moscow, Russia.
authors: Yuri
authors: Y
authors: Stozhkov
authors: Faculty of Physics, University of Vienna, 1090 Vienna, Austria.
authors: Frank
authors: F
authors: Stratmann
authors: Laboratory for Systems, Instrumentation and Modeling in Science and Technology for Space and the Environment, University of Lisbon and University of Beira Interior, 1849-016 Lisbon, Portugal.
authors: Antonio
authors: A
authors: Tomé
authors: Department of Applied Physics, University of Eastern Finland, FI-70211 Kuopio, Finland.
authors: Annele
authors: A
authors: Virtanen
authors: Department of Experimental Physics, CERN (European Organization for Nuclear Research), CH-1211 Geneva, Switzerland.
authors: Alexander Lucas
authors: AL
authors: Vogel
authors: Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany.
authors: Andrea C
authors: AC
authors: Wagner
authors: Faculty of Physics, University of Vienna, 1090 Vienna, Austria.
authors: Paul E
authors: PE
authors: Wagner
authors: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
authors: Ernest
authors: E
authors: Weingartner
authors: Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Daniela
authors: D
authors: Wimmer
authors: Faculty of Physics, University of Vienna, 1090 Vienna, Austria.
authors: Paul M
authors: PM
authors: Winkler
authors: Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA 15213.
authors: Penglin
authors: P
authors: Ye
authors: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125.
authors: Xuan
authors: X
authors: Zhang
authors: Institute for Ion and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria; Ionicon Analytik GmbH, 6020 Innsbruck, Austria.
authors: Armin
authors: A
authors: Hansel
authors: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
authors: Josef
authors: 0000-0002-0006-0009
authors: J
authors: Dommen
authors: Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA 15213.
authors: Neil M
authors: 0000-0003-3054-2364
authors: NM
authors: Donahue
authors: Helsinki Institute of Physics, University of Helsinki, FI-00014 Helsinki, Finland; Department of Applied Physics, University of Eastern Finland, FI-70211 Kuopio, Finland; Aerodyne Research Inc., Billerica, MA 01821.
authors: Douglas R
authors: DR
authors: Worsnop
authors: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
authors: Urs
authors: U
authors: Baltensperger
authors: Helsinki Institute of Physics, University of Helsinki, FI-00014 Helsinki, Finland; Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland.
authors: Markku
authors: M
authors: Kulmala
authors: Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany.
authors: Joachim
authors: J
authors: Curtius
authors: School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom; hamish.gordon@cern.ch k.s.carslaw@leeds.ac.uk.
authors: Kenneth S
authors: 0000-0002-6800-154X
authors: KS
authors: Carslaw
mesh_terms: D000336:Aerosols / Q000032:analysis* / Q000737:chemistry; D000393:Air Pollutants / Q000032:analysis / Q000737:chemistry; D001272:Atmosphere / Q000032:analysis* / Q000737:chemistry; D002980:Climate; D003198:Computer Simulation; D049671:History, 18th Century; D049672:History, 19th Century; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D000067896:Industrial Development / Q000266:history; D015233:Models, Statistical; D035501:Uncertainty
chemical_list: D000336:Aerosols; D000393:Air Pollutants
keywords: aerosol; biogenic; climate; forcing