CERN CLOUD Experiment Challenges Climate Models

By Kennedy Maize

Washington, D.C., August 25, 2011 — The long-anticipated CERN study of the impact of cosmic rays on formation of clouds in the atmosphere, published today in Nature, should prompt a major revision of the global circulation models that support claims of man-made climate warming. The CLOUD study by CERN, the European nuclear research agency, finds that cosmic rays from the sun, not man-made particles, are involved in the formation of the vast major of atmospheric aerosols.

In a briefing paper supporting its CLOUD (Cosmics leaving Outdoor Droplets) experimental results, CERN notes that “it is clear that the treatment of aerosol formation in climate models will need to be substantially revised, since all models assume” that atmospheric particulates are caused by trace pollutants and water vapor. “It is now urgent to identify the additional nucleating vapors, and whether their sources are mainly natural or from human activities.”

Jasper Kirby, lead physicist of the CLOUD experiment, said in a CERN press release, “We’ve found that cosmic rays significantly enhance the formation of aerosol particles in the mid troposphere and avove. These aerosols can eventually grow into the seeds for clouds. However, we’ve found that the vapors previously thought to account for all aerosol formation in the lower atmosphere can only account for a small fraction of the observations — even with the enhancement of cosmic rays.”

The CLOUD results show that a few kilometers into the atmosphere, sulfuric acid and water vapor can form clusters and that cosmic rays cans enhance the formation by a factor of ten or more. In the lowest layers of the atmosphere, up to about a kilometer, other vapors such as ammonia are needed for the formation of the clusters. But the H2SO4, water and ammonia, even with enhancement from cosmic rays, don’t explain the quantity of aerosol formation, says CERN. So additional vapors must be involved.

Says Kirby, “It was a big surprise to find that aerosol formation in the lower atmosphere isn’t due to sulfuric acid, water and ammonia alone. Now it’s vitally important to discover which additional vapors are involved, whether they are largely natural or of human origin, and how they influence clouds. This will be our next job.”

The experiment used a beam of particles from CERN’s Proton Yynchrotron accelerator to provide a controllable source of cosmic rays to be injected into a state-of-the-art chamber to replicate the atmosphere.

The CERN statements are careful not to overstate the results of CLOUD, which have been awaited in the atmospheric science community for years. Says the briefing paper, “This result leaves open the possibility that cosmic rays could also influence climate. However, it is premature to conclude that cosmic rays have a significant influence on climate until the additional nucleating vapors have been identified, their ion enhancement measured, and the ultimate effects of clouds have been confirmed.”

Particulates and clouds play a large, and not well-understood, component of how the global climate behaves. MIT meteorologist Richard Lindzen, long a powerful skeptic of man-made global warming, is an expert on clouds and has criticized climate models in the past for not  incorporating cloud phenomena very skillfully.

Science writer Andrew Orlowski in the UK online science and technology magazineThe Register commented today, “Unsurprisingly, it’s a politically sensitive topic, as it provides support for a ‘heliocentric’ rather than an ‘anthropogenic’ approach to climate change: the sun plays a large role in modulating the quantity of cosmic rays reaching the upper atmosphere of the Earth.”