VISIONARIES

Saving the Planet, One Cloud at a Time
By Patrick Tucker
Two British researchers offer an ambitious plan to save the world from global warming.

There are thousands of ways to battle climate change, from supporting solar and wind power to buying low-energy appliances to simply consuming less. But what if these measures, taken en masse and individually, come up short? If humanity just can’t be bothered to save itself before runaway climate change takes over, is there a Plan B?

Perhaps.

British atmospheric physicist John Latham and engineer Stephen Salter have come up with a scheme to attack global warming directly. By blasting seawater droplets into the air from wind-powered ships, they believe stratocumulus clouds could be made thick and white enough to bounce more solar radiation back into space to change the earth’s temperature.

THE FUTURIST magazine talked to Latham about changing the climate, for good.

THE FUTURIST: Why do you think your idea is receiving special attention right now? Would you call something like this a desperation measure to be implemented only after all else has failed?

John Latham: I think the increased attention results from increasing public consciousness and concern regarding global warming. If our idea works as computations indicate, it could hold the earth’s temperature constant in the face of increasing atmospheric CO₂ concentrations for at least 50 years.

The best solution by far is to reduce CO₂ emissions to the point where any temperature rise is not dangerous. I do not think this will happen, so we need to develop (hopefully not deploy) stopgap measures to stabilize temperature for however long it takes to develop a clean primary energy source. It is, in a sense, a desperation measure, but it is also an attempt to restore climate as best as possible to how it was before the warming.

FUTURIST: You’re seeking funds right now to test the idea. How might you go about testing it?

Latham: [We would have] a limited-area field experiment in which selected areas of a region of marine stratocumulus clouds are seeded with seawater particles, whilst adjacent areas are not.… A range of instruments are used to determine if seeding causes an increase in cloud brightness, and if so, how much.

FUTURIST: The challenges to implementing such a system must be enormous. What are the biggest ones?

Latham: It actually is not a very daunting prospect. The costs are such that economists say they can be regarded as zero in comparison with those of damage caused by unbridled warming. The largest current problem is developing the spray technology.

FUTURIST: You have discussed the possibility of unintended consequences to such a system. What might they be?

Latham: It is inevitable that our scheme will modify global temperature, rainfall, and wind distributions to some degree. It is vital, therefore, to examine fully — largely by major global modeling — all possible ramifications of its possible deployment. If there are significant adverse ones which cannot be eliminated, the scheme should not be deployed.

FUTURIST: Was there any particular moment of epiphany where you were considering the effects of saltwater in the atmosphere and realized you had happened upon an idea that might one day save the entire world?

Latham: About 35 years ago, my 10-year-old son Mike and I were watching a gorgeous sunset over the Irish Sea from a Welsh mountain. He asked why the clouds were gleaming, and I told him they were reflecting sunlight, like mirrors. He laughed and said, “soggy mirrors.” That comment stuck with me and I think provided, almost 20 years later, the stimulus that gave rise to my 1990 Nature paper first proposing the idea.

About the Interviewer

Patrick Tucker is senior editor of THE FUTURIST and director of communications for the World Future Society.

For more information, contact: The National Center for Atmospheric Research, www.ucar.edu.