cloud brightening

Ideas for potential technologies that could artificially cool the planet as a countermeasure against global warming have been considered radical and dangerous for a long time. But as climate change continues to become increasingly apparent, ideas like solar geoengineering are gaining increasing attention.

Most environmental organizations are at best skeptical about such ideas and oppose them. Their opposition is in part based on the assertion that there are no quick fixes for climate change and that not addressing its root causes is a dangerous path to take. But an even greater concern is that intentionally manipulating global temperatures is likely to have a host of unintended consequences that could prove disastrous.

One of the world’s largest environmental organizations, the Environmental Defense Fund, has decided to fund research into solar geoengineering. The EDF cautions that is in not in favor of deploying such technology. Its position is that the discussion about ways to cool the planet is not going away and cannot be ignored. The lack of proper research can promote unfounded optimism about such technology So, they are going to fund research that can provide information based on solid, well-formulated science.

A major focus will be what other effects technologies like cloud brightening and injecting aerosols into the atmosphere might have apart from providing cooling.

The EDF’s own position is that deliberate climate interventions present serious ecological, moral, and geopolitical concerns. However, they believe that policymakers need to be informed by the most accurate information possible.

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Environmental Group to Study Effects of Artificially Cooling Earth

Photo, posted February 3, 2008, courtesy of Camilla Cannarsa via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar geoengineering is a type of climate intervention: deliberate actions designed to affect the climate. There are several ways to try to reduce the amount of sunlight reaching the surface of the earth and all of them are controversial. Perhaps the least controversial approach is cloud brightening.

The idea is based on something called the Twomey effect, which is that large numbers of small droplets in the atmosphere reflect more sunlight than small numbers of large droplets. Spraying vast quantities of minuscule aerosols into the sky, thereby forming many small droplets, could change the reflective properties of clouds. If clouds are more reflective, then less sunlight reaches the surface, and the temperature goes down.

This form of geoengineering is thought to be less risky because it can be performed on a localized basis and can use relatively benign materials such as sea salt.

In early April, scientists from the University of Washington started testing a device that sprays tiny sea-salt particles into the air from the deck of a decommissioned aircraft carrier in Alameda, California. The test was simply to see whether the machine propelled a mist of suitable size.

Within two weeks, Alameda officials ordered a stop to the experiment, citing potential health and environmental risks. After a month-long investigation, Alameda ruled that the experiment does not generate a measurable risk to health, wildlife, or the environment.

But before more ambitious experiments take place, there are potential side effects of cloud brightening that need to be studied. It may turn out to be a useful tool in fighting global warming, but in any case, such technology should not be viewed as a substitute for moving away from fossil fuels.

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A Test of Cloud-Brightening Machines Poses No Health Risk, Officials Say

Photo, posted September 8, 2011, courtesy of Justin Ladia via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio