Scientists consider 'cloud brightening' to slow global warming

"There's a science question about can we do it, but there's also an ethical question about should we do it, and a policy question about how would we do it," researcher Thomas Ackerman said.
By Brooks Hays  |  July 25, 2017 at 4:52 PM
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July 25 (UPI) -- Scientists at the University of Washington are considering the prospects of a controversial climate change solution called "marine cloud brightening."

Most agree the best solution to climate change is the curbing of carbon emissions -- by reducing the burning of fossil fuels, as well as increasing the adoption of renewable energy sources.

But if efforts to curb emissions fall short or prove insufficient, emergency solutions may be necessary to avoid the most catastrophic consequences of global warming. Enter marine cloud brightening, a climate engineering solution.

Clouds form when water droplets condense on particles in the air and coalesce in the atmosphere. Higher concentrations of particulates allow smaller water droplets to form clouds, yielding bigger, whiter clouds that reflect sunlight instead of absorbing heat.

Researchers at the University of Washington have proposed spraying particulates over the ocean to encourage the formation of solar energy-reflecting marine clouds. They published their proposal this week in the journal Earth's Future.

Some climate scientists believe marine cloud brightening is already happening as a result of an increase in air pollution since the dawn of the Industrial Revolution. The phenomenon may be offsetting a small percentage of the greenhouse gas effect, but measuring how much has proven difficult.

"Testing out marine cloud brightening would actually have some major benefits for addressing both questions," Rob Wood, a professor of atmospheric sciences at Washington, said in a news release. "Can we perturb the clouds in this way, and are the climate models correctly representing the relationship between clouds and aerosols?"

Wood and his research partners are currently seeking public and private fundings for their work.

Their team aims to develop an efficient aerosol spraying device and test its ability to eject particles in the lab. The researchers must also find an ideal place to test their marine cloud brightening technology -- somewhere without significant pollution and sufficient rates of marine cloud formation.

"We're talking about some kind of new world in terms of the ethical issues," said Thomas Ackerman, also a professor of atmospheric sciences. "But for climate, we're no longer in an era of 'do no harm.' We are altering the climate already. It's now a case of 'the lesser of two evils.'"

Ackerman and his colleagues aren't yet endorsing large-scale marine cloud brightening. They just want to test the solution's potential.

"There's a science question about can we do it, but there's also an ethical question about should we do it, and a policy question about how would we do it," Ackerman said. "I'm an agnostic on this. I want to test geoengineering and see if it works. But the whole time we're working on this, I think we need to still be asking ourselves: 'Should we do it?'"

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