"We do not have enough scientific information to predict how these high flight rates will affect the ozone layer in 10 or 20 years."
Further complicating matters, individual mission trajectories pollute to different degrees, he added.
Some launches release chemicals into the lower atmosphere, where most of them "rain out" fairly quickly. Others pollute the stratosphere, where they can linger and react with other chemicals.
Also, "we don't know enough about the real atmospheric impacts of all the various types [of fuels] to say for sure which are best," study co-author Toohey said.
"We need to get some observations in a variety of rockets to start to reduce uncertainties."
Global Warming vs. Ozone
Toohey is also sending out a pollution warning about so-called geoengineering proposals that have surfaced to combat global warming.
Some researchers, for example, want to seed the stratosphere with particles of sulfur dioxide and aluminum oxide to spur global cooling. (Read "Extreme Global Warming Fix Proposed: Fill the Skies With Sulfur.")
But aluminum oxide is one of the chemicals in solid rocket fuel that depletes ozone, Toohey pointed out.
"There are people in the engineering world who think we could address global warming in a way that could destroy our ozone layer," he said.
"If people are going to put particles into the stratosphere, they'd better be careful."
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