Dash of salt in clouds may fight global warming, UW scientist says

Aug 20, 2012

By Todd Bishop of Geekwire

A group of scientists, including a University of Washington atmospheric physicist, wants to test the theory that pumping sea salt into the sky over the ocean would combat global warming by creating clouds that reflect more sunlight back into space.

The experiment in “marine cloud brightening” is proposed by scientists including the UW’s Rob Wood in the journal Philosophical Transactions of the Royal Society. The idea is to conduct a small-scale experiment to see if the approach would have the desired effect without unexpected consequences.

The theory is that water droplets will form around the particles of salt in the air to create big, long-lasting clouds.

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A phenomenon that inspired marine cloud brightening is ship trails: clouds that form behind the paths of ships crossing the ocean, similar to the trails that airplanes leave across the sky. Ship trails form around particles released from burning fuel.
Credit NASA

In this UW article on the topic, Wood tells UW writer Nancy Gohring that the goals of the researchers are purely scientific. “I would rather that responsible scientists test the idea than groups that might have a vested interest in proving its success.”

He acknowledges that it’s not a long-term solution to global warming. “It’s a quick-fix idea when really what we need to do is move toward a low-carbon emission economy, which is turning out to be a long process,” he says. “I think we ought to know about the possibilities, just in case.”

The researchers would conduct the experiments initially from sprayers on a ship or barge, and they’ve put forward a conceptual image (above) showing an unmanned, remote-controlled ship that could spray the salt into the sky.

Others who have proposed similar ideas in “geoengineering” include Nathan Myhrvold, the former Microsoft chief technology officer, whose “Stratoshield” would inject sulfur dioxide into the stratosphere, aiming for a similar effect.