The concept of geoengineering is as old as science-fiction novels â€" but never would the greatest of imaginations 100 years ago have predicted that today, geophysicists are proposing field experiments to manipulate clouds.
Rob Wood, assistant professor of atmospheric sciences at the University of Washington, says that among the ways to combat global warming is by decreasing the amount of sunlight directly hitting the Earth.
Wood's current research project employs that method. Wood and his team of researchers recently published a paper on marine-cloud brightening that proposes a way to make clouds reflect more sunlight and, ultimately, slow down global warming.
Their proposed experiment is to shoot saltwater particles into the sky, increasing marine clouds' surface area and making the clouds brighten and reflect more sunlight. Clouds already reflect about 50 percent of the sunlight that hits them, but the researchers hypothesize that this experiment may increase clouds' reflexivity to 60 percent.
Carbon emissions, and greenhouse gases in general, continue to be a major concern that scientists say could lead to catastrophic climate change soon, which is why Wood believes it's important to move forward with field experiments.
The research has been tested through computer simulations, but there are still many factors the researchers say the models cannot account for. Wood says when the experiment is conducted, it's possible that the clouds might not brighten at all with the particles.
"We may well fail," he said.
That possibility makes it all the more important for scientists to test out the theory.
"These solutions discussed as a quick fix â€" frankly, they're probably not going to end up like that. There's going to be all kinds of side effects; there's going to be all kinds of problems with them that would make them more complicated than we initially thought," Wood said. "The sooner we know about those, the sooner we can maybe take these geoengineering ideas off the table."
"I think we have a responsibility to look at these ideas that have been put out there. We're not going to know whether or not this will work until we do some kind of testing."
John Latham, lead author of the paper published in Philosophical Transactions of the Royal Society this month, first published his work on cloud brightening in 1990. Since then, some of the brightest minds in science have contributed to the research to come up with this proposal.
There are many approaches to testing the marine-cloud brightening hypothesis, but one idea particularly captures the imagination. An image that often accompanies the research is one of a wind-powered ship with cylindrical vessels, which would shoot saltwater particles into the atmosphere.
"That ship as it is drawn is the most ideal vision. ... It's a particularly adventurous idea of an ideal vessel for doing that kind of work," said Phil Rasch, a researcher working with Wood, chief scientist for climate science at the Pacific Northwest National Laboratory (PNNL), and a UW alumnus.
But Wood said that idea would be very expensive.
With the Budget Control Act looming in 2013, which threatens to cut up to 10 percent of federal research funding at public universities, it's tough to see projects like the wind-powered ship actually being pursued.
"(The cut) would be very, very devastating to science," Wood said.
Cheaper options for a field experiment are out there, and researchers say geoengineering is worth investing in.
Rasch said some of the biggest challenges to geoengineering research involve understanding the consequences of its actions â€" unlike other research experiments, the effects of geoengineering experiments are on a global scale.
Scientists' limited knowledge on the climate effects of cloud brightening is just one example. Geoengineering strategies to decrease carbon-dioxide emissions is an "inexact compensation." Some parts of the planet would benefit more than others, which brings up both ethical and political challenges.
"There will be winners and losers," Rasch said. "Certain parts of the world will be more closely compensated for than others. ... And how do you decide which of the parts are more important?"
But the proposed marine cloud-brightening experiment shouldn't create significant changes to the climate. The experiment would be conducted in the middle of the ocean with saltwater particles, so nothing unnatural would be shot into the atmosphere.
Wood looks at these field experiments on cloud brightening as a responsibility. He said that when scientists, as opposed to governments or individual groups, invest in an experiment, they should have the right motives and more transparency can be ensured.
"Global warming is a serious problem," Wood said, which urges geoengineers to continue working on finding ways to mitigate that problem.
And, of course, there's the factor of curiosity.
"Different science has different values to society," Wood said, "But people want to know what's out there."
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