Altering clouds could limit climate change

Wednesday , January 09, 2013 - 5:01 PM

James Temple

One afternoon last fall, Armand Neukermans, a tall engineer with a sweep of silver bangs, flipped on a noisy pump in the back corner of a Sunnyvale, Calif., lab. Within moments, a fine mist emerged from a tiny nozzle, a haze of saltwater under high pressure and heat.

This seemingly simple vapor carries a lot of hope -- and inspires a lot of fear. If Neukermans’ team of researchers can fine-tune the mechanism to spray just the right size and quantity of salt particles into the sky, scientists might be able to make coastal clouds more reflective.

The hope is that by doing so, humankind could send more heat and light back into space, wielding clouds as shields against climate change.

The fear, at least the one cited most often, is that altering the atmosphere this way could also unleash dangerous side effects.

“Ten years ago, people would have said this is totally wacky,” Neukermans said. “But it could give us some time if global warming really becomes catastrophic.”

It’s now beyond debate that the globe is getting hotter. The ice caps are melting, sea levels are rising, and extreme weather events like droughts, floods and hurricanes are increasing.

Neukermans and his colleagues are among an unofficial cadre of scientists, technologists, designers and engineers who have begun the hard work of preparing for a warmer world.

It’s not clear yet if any will work, or find the support to move off the drawing board. All are sure to be costly and controversial.



The concept of “cloud brightening” dates back 22 years, when British physicist John Latham first proposed it in a little-noticed paper in the journal Nature.

But as the threat of global warming rises, it and other “geoengineering” strategies have shifted from the scientific fringes into mainstream debate. Geoengineering is a broad category for techniques that could remove greenhouse gases from the atmosphere or reflect away more heat, including things as innocuous as painting roofs white and as controversial as spraying sulfate particles into the stratosphere.

The basic idea behind cloud brightening is to equip ships with mechanisms like the ones Neukermans’ team is designing and aim them at the relatively low-lying clouds that hug the western coasts of continents. It would probably require hundreds -- if not thousands -- of vessels.

“If we have to intervene, we should be doing the research now, because these ideas are extremely complicated and extremely risky,” said Jane Long, a former associate director at Lawrence Livermore National Laboratory.

Critics, however, argue that scientists are talking about tinkering with a system they don’t fully understand. Altering the clouds could affect rainfall patterns, with potentially devastating consequences, they say.

“Large and small, these things all have other environmental effects and they’re not solving the problem,” said Kert Davies, research director at environmental group Greenpeace. He believes research efforts and dollars should be focused instead on clean-energy technology.

Neukermans, a 72-year-old serial inventor from Belgium, agrees that the best response to climate change is to curtail greenhouse emissions.

Cloud brightening is “absolutely no replacement for the other things we should do,” he said. “We should cut CO2 as much and as fast as we can.”

Neukermans arrived in the United States in 1964. Over a four-decade career at General Electric, Hewlett-Packard, Xerox and elsewhere, he put his name on more than 75 patents. Since retiring, Neukermans has dedicated his time and money to a series of social and environmental causes, including efforts to develop land-mine-detection technology and inexpensive prostheses for the poor.

He turned his attention to cloud brightening in early 2010, recruiting a team made up mostly of former colleagues, after the Bill Gates-supported Fund for Innovative Climate and Energy Research provided money for an initial viability test.

It’s clear that cloud brightening is possible. Satellites have observed “ship tracks,” or whitened lines in marine clouds that large vessels have formed inadvertently by pumping out particles in their exhaust. Unknown is whether humans can do it purposely, on a large enough scale to matter, and without severely altering weather patterns elsewhere.

Last September, scientists called for limited field trials once a nozzle technology is developed. But is preventing any fallout from such testing an achievable goal? And is it possible for all affected parties to reach consensus on these issues?

Wil Burns is dubious.

The director of the energy policy and climate program at Johns Hopkins University terms himself an “extreme skeptic” of cloud brightening. Even if it works, he’s not convinced scientists will be able to easily identify or deal with any unintended consequences.

There’s also the touchy question of social equity. Cloud brightening might cool global temperatures on average, but what if it leads to deforestation in South America or affects monsoon patterns in Asia? If the world is better off on average -- particularly in the relatively temperate first world -- is it acceptable that some nations suffer?

And even if geoengineering initially works, researchers might run into some disastrous side effect that only becomes clear over time, forcing them to cut off those efforts after a few years or decades.

“If you stopped, you’d get a massive carbon pulse and temperature increases as much as 10 to 30 times greater than if you’d continued climate change policy as it is,” Burns said. “It would just be catastrophic.”

(Reach James Temple at jtemple@)sfchronicle.com. Distributed by Scripps Howard News Service, shns.com.)

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