Clouds Have a Role in Climate Change, Scientists Say, but Will They Help or Harm?

Pam Wright
Published: November 9, 2017

The coal-fueled Fiddlers Ferry power station emits vapor into the night sky on Nov. 16, 2009, in Warrington, United Kingdom.
(Christopher Furlong/Getty Images)

As greenhouse gases continue to warm the planet, Earth will reorganize itself to counter the effects, scientists say, and clouds will have an important role in how that plays out.

The question is whether changing cloud patterns will warm the planet faster or slower, and whether controversial geoengineering techniques might help protect the planet from the ravages of climate change.

According to NASA, clouds not only cool the Earth by reflecting sunlight, but they also trap heat much like greenhouse gases. Scientists agree clouds will have a leading role in the how fast the Earth warms, but the net effect of the changing cloud patterns on climate change will depend on the types of clouds, their thickness and where they occur.

For a time, scientists believed clouds might be the "white knight that would rescue us from climate change," according to NASA. But today, scientists are far less certain.

Because of this uncertainty, scientists are scrambling to figure out the mystery of how cloud patterns will change with global warming and what that might mean for the fate of mankind. They are also looking at ways human intervention might alter the clouds to the planet's advantage.

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One such study that appeared in the September issue of the Proceedings of the National Academy of Sciences of the United States pointed to the uncertainty of clouds and global warming, an uncertainty that has V. "Ram" Ramanathan of the Scripps Institution of Oceanography in San Diego and co-author of the study concerned.

In experiments on the behavior of clouds in connection with global warming, one indicated that low-level cloud systems that shade oceans near the equator seem to be moving toward the poles, E&E News noted.

"That is a big worry. It's amplifying the heat, moving in the wrong direction," Ramanathan told the media outlet.

In another, Ramanathan and his colleague, Yangyang Xu, used satellites and drones to study the effects of pollutants on clouds over the Indian Ocean. They learned pollutants that create "Asian brown clouds" absorb more heat, which changes air movement or turbulence and reduces their size and ability to shade the Earth from the sun.

NASA points out that people assume more water will evaporate with global warming, creating more clouds. But in reality, a warmer atmosphere "needs more water vapor molecules to become saturated and to condense into clouds, so it is hard to anticipate exactly how clouds respond to human-induced climate perturbations."

"For example, although summer is warmer than winter, and the humidity is usually higher in summer, nevertheless the sky is not noticeably cloudier on average in summer than in winter," NASA notes.

Scientists Explore Controversial 'Geoengineering' Methods

Other scientists are exploring methods that would use clouds to help curb climate change.

On Wednesday, Joseph Majkut, director of climate policy at the Niskanen Center, a Washington D.C. think tank, and Philip J. Rasch, chief climate scientist for the Pacific Northwest National Laboratory in Richland, Washington, testified before the House Committee on Science, Space and Technology, held to explore "geoengineering," or the deliberate large-scale manipulation of the environment to counteract the effects of climate change, McClatchy DC reported.

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Majkut and Rasch commented on the possibility of "cloud brightening," or seeding marine clouds with salt water or other particles that would, theoretically, increase their ability to reflect solar rays, thereby cooling the Earth. The method is part of a branch of science known as “sunlight reflection methods,” or SRM.

SRM is controversial because some scientists worry that seeding clouds will impact rainfall or have some other unintended effect, McClatchy noted. Others say such talk merely distracts from the most important deterrent to global warming — reducing carbon emissions.

Still, scientists are studying all scenarios in the race to save the planet from the harmful effects of human-induced climate change.

“We think SRM could buy time for other (carbon-reduction) measures to be put in place,” Rasch told the committee.

“If the worst-case scenarios of global warming come to pass, these technologies could be used to help people, saving lives and economies from the worst effects of climate change,” Majkut added.

While geoengineering may provide tools in curbing global warming, scientists agree that the primary driver in reducing climate change is reducing harmful greenhouse gases that come from burning fossil fuels.

In a letter penned by 24 scientists and environmental advocates, it was emphasized that “any consideration of a federally funded and coordinated research program into geoengineering must be in the context of a strategic portfolio of responses to climate change.”

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.