Sunscreen in the Sky? Reflective Particles May Combat Warming
Titanium dioxide could scatter sunlight and cool Earth, scientist says.
The plan involves using high-altitude balloons to disperse millions of tons of titanium dioxide—a nontoxic chemical found in sunscreen as well as in paints, inks, and even food.
Once in the atmosphere, the particles would spread around the planet and reflect some of the sun's rays back into space.
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.
(Related: "'Ice Shield' Experiment Aims to Cool Mongolian City.")
The idea was inspired by the 1991 eruption of Mount Pinatubo, a volcano in the Philippines, said Davidson, head of the