Could putting sunscreen in the sky combat warming?

Scientists want to spray titanium dioxide into the stratosphere to counteract the effects of global warming.

Scientists are looking to the protective power of sunscreen to combat global warming.

Chemical engineer Peter Davidson is championing an idea to spray titanium dioxide, an ingredient in sunscreen, into the sky to reflect some of the sun’s rays back into space to cool Earth.

The plan is to carry the nontoxic chemical up to the stratosphere in high-altitude balloons and then spray the particles into the stratosphere.

National Geographic News reports:

"About three million tons of titanium dioxide—spread into a layer around a millionth of a millimeter thick—would be enough to offset the warming effects caused by a doubling of today's atmospheric carbon dioxide levels, according to project leader and chemical engineer Peter Davidson."

This is just another in a series of geoengineering projects scientists have come up with to combat global warming. But this one, Davidson say, has a good chance of working out right.

To show how this method might work, Davidson points to the eruption of Mount Pinatubo. When this volcano erupted in the Philippines in 1991, it sprayed millions of tons of sulfur dioxide into the stratosphere. The sulfur dioxide created a layer of sulfuric acid in the air “that reduced global temperatures by about a quarter of a degree Fahrenheit (half a degree Celsius) for two years,” National Geographic News reports.

Unlike sulfuric acid, which causes ozone depletion, titanium dioxide has no known harmful effects.

And the method devised for getting the titanium oxide up there, a balloon-dispersal system, is cheaper than previously thought up plans, which involved rockets or aircrafts.

“Project leader Davidson estimates that his balloon dispersal system would cost between U.S. $800 million and $950 million a year, plus $2 billion to $3 billion annually for the titanium dioxide,” National Geographic News says.

Of course, we still don’t know what effect any method of climate intervention will have on the planet. But Davidson doesn't see his idea being deployed for at least a few decades so there's no need to worry. In the meantime, it's probably best to wear sunscreen on those hot days.

Sunscreen in the Sky? Reflective Particles May Combat Warming  [National Geographic News]

Photo via flickr/Michael Kirwan

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