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Clouds provide clue to better climate predictions

Date:
May 25, 2016
Source:
Carnegie Mellon University
Summary:
A research group from the CERN Cloud experiment has uncovered the processes behind the formation and evolution of small atmospheric particles free from the influence of pollution. Their findings are key to creating accurate models to understand and predict global climate change.
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A research group from the CERN Cloud experiment, including scientists from Carnegie Mellon University's College of Engineering and Mellon College of Science, has uncovered the processes behind the formation and evolution of small atmospheric particles free from the influence of pollution. Their findings are key to creating accurate models to understand and predict global climate change. The findings are published in the May 26 issue of Nature.

Clouds and aerosols-small airborne particles that can become the seeds upon which clouds form-are essential to climate predictions because they reflect sunlight back into space. Reflecting light away from Earth can have a cooling effect, masking some of the warming caused by greenhouse gases.

"The best estimate is that about one-third of the warming by greenhouse gas emissions is masked by this aerosol cooling, but the fraction could be as large as half and as little as almost nothing," says Neil Donahue, professor of chemical engineering, engineering and public policy, and chemistry at Carnegie Mellon.

In order to have complete climate prediction models, scientists need to incorporate clouds and aerosols into their calculations, but understanding how new aerosol particles form and grow in the atmosphere, and how they affect clouds and climate, has been challenging.

Scientists involved with CERN's CLOUD experiment study use a large chamber to simulate the atmosphere and track the formation and growth of aerosol particles and the clouds they seed. The latest research shows that new particles can form exclusively from the oxidation of molecules emitted by trees without the presence of sulfuric acid. Sulfuric acid largely arises from fossil fuels, so the new findings provide a mechanism by which nature produces particles without pollution.

"This softens the idea that there may be many more particles in the atmosphere today due to pollution than there were in 1750, and suggests that the pristine pre-industrial climate may have had whiter clouds than presently thought," says Donahue.

The team's research has lasting climate implications.

"Earth is already more than 0.8C than it was in the pre-industrial epoch, and this is with some masking by aerosol particles. As the pollution subsides, up to another 0.8C of hidden warming could emerge," says Donahue.


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Materials provided by Carnegie Mellon University. Note: Content may be edited for style and length.


Journal Reference:

  1. Jasmin Tröstl, Wayne K. Chuang, Hamish Gordon, Martin Heinritzi, Chao Yan, Ugo Molteni, Lars Ahlm, Carla Frege, Federico Bianchi, Robert Wagner, Mario Simon, Katrianne Lehtipalo, Christina Williamson, Jill S. Craven, Jonathan Duplissy, Alexey Adamov, Joao Almeida, Anne-Kathrin Bernhammer, Martin Breitenlechner, Sophia Brilke, Antònio Dias, Sebastian Ehrhart, Richard C. Flagan, Alessandro Franchin, Claudia Fuchs, Roberto Guida, Martin Gysel, Armin Hansel, Christopher R. Hoyle, Tuija Jokinen, Heikki Junninen, Juha Kangasluoma, Helmi Keskinen, Jaeseok Kim, Manuel Krapf, Andreas Kürten, Ari Laaksonen, Michael Lawler, Markus Leiminger, Serge Mathot, Ottmar Möhler, Tuomo Nieminen, Antti Onnela, Tuukka Petäjä, Felix M. Piel, Pasi Miettinen, Matti P. Rissanen, Linda Rondo, Nina Sarnela, Siegfried Schobesberger, Kamalika Sengupta, Mikko Sipilä, James N. Smith, Gerhard Steiner, Antònio Tomè, Annele Virtanen, Andrea C. Wagner, Ernest Weingartner, Daniela Wimmer, Paul M. Winkler, Penglin Ye, Kenneth S. Carslaw, Joachim Curtius, Josef Dommen, Jasper Kirkby, Markku Kulmala, Ilona Riipinen, Douglas R. Worsnop, Neil M. Donahue, Urs Baltensperger. The role of low-volatility organic compounds in initial particle growth in the atmosphere. Nature, 2016; 533 (7604): 527 DOI: 10.1038/nature18271

Cite This Page:

Carnegie Mellon University. "Clouds provide clue to better climate predictions." ScienceDaily. ScienceDaily, 25 May 2016. <www.sciencedaily.com/releases/2016/05/160525161542.htm>.
Carnegie Mellon University. (2016, May 25). Clouds provide clue to better climate predictions. ScienceDaily. Retrieved May 23, 2017 from www.sciencedaily.com/releases/2016/05/160525161542.htm
Carnegie Mellon University. "Clouds provide clue to better climate predictions." ScienceDaily. www.sciencedaily.com/releases/2016/05/160525161542.htm (accessed May 23, 2017).

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