Clouds And Aerosols Can Be Vital To Understand And Predict Climate Change

Studying cloud formation has led a team of researchers from the CERN Cloud experiment to disclose the processes driving the formation and evolution of small atmospheric particles that are free of pollution. With this information, scientists can use accurate models to predict climate change and enhance our understanding of processes driving it.

Due to the reflective ability of clouds and aerosols, or tiny particles that can become the basis for cloud formation, scientists are examining them to understand their ability to protect the earth from sunlight and mask the warming from greenhouse gases. Understanding this process is important to arrive at accurate climate predictions.

"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," said Neil Donahue of Carnegie Mellon University and co-author of the study.

Even though clouds and aerosols are important in climate prediction models, understanding their links with atmosphere and climate is also a challenge.

In the CERN CLOUD study, a large chamber was used to replicate the atmosphere and probe the formation and growth of aerosol particles as well as the clouds they form. Results show that new particles can arise from the oxidation of molecules from trees that are separate from sulfuric acid originating from fossil fuels. Hence, experts get an insight into understanding the production of 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," Donahue said.

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

The findings were published in the May 25 issue of the journal Nature.