American Scientists Propose Using Aircraft to Spray Ice at 17km Altitude to Reduce Stratospheric Water, Helping to Cool the Earth
A team of scientists from the National Oceanic and Atmospheric Administration (NOAA) and NASA has put forward a new idea to cool the Earth, as reported by Phys on February 29. Water vapor is a natural greenhouse gas that retains heat, similar to CO2 produced from burning coal, oil, and gas. Therefore, the researchers propose that if ice could be sprayed into the upper atmosphere, that region would become drier, helping to slightly mitigate the warming caused by human activities. This new research was published in the journal Science Advances.
Experts propose drying the upper atmosphere to cool the Earth. (Photo: Max Dollner/Vienna University)
“This is not something we can implement right now. We are merely exploring what might be feasible in the future and identifying research directions,” said Joshua Schwarz, a physicist at NOAA and the lead author of the study.
The Method of Drying the Upper Atmosphere works as follows. First, high-tech aircraft would spray ice particles at an altitude of about 17km, just below the stratosphere, where the air rises slowly. Then, the ice and cold air rise to the coldest areas, causing water vapor to freeze and fall, thereby reducing moisture in the stratosphere. However, the world currently lacks effective technology to spray ice in such a manner.
Schwarz noted that at a maximum of 2 tons of ice sprayed per week, the amount of water vapor removed could be enough to reduce warming slightly, about 5% of the total warming caused by carbon from fossil fuel combustion. This level is modest and should not be considered a substitute for pollution reduction, according to Schwarz. He is unsure of the potential side effects, which is a concern shared by many other scientists.
Deliberately modifying the Earth’s atmosphere to combat climate change could create many new problems, according to climate scientist Andrew Weaver at Victoria University. Weaver stated that while the new idea may be technically reasonable, he compares it to a children’s story about a king who loves cheese but has trouble with mice. The king uses cats to deal with the mice, then has to use dogs to chase the cats, followed by lions to eliminate the dogs, elephants to remove the lions, and ultimately returns to using mice to scare away the elephants. Weaver suggests that it would be more sensible to address the root problem – the cheese or CO2.
