Scientists have been pondering whether intentionally drying the Earth’s stratosphere could be a way to tackle the climate crisis (other than, y’know, stop burning ridiculous amounts of fossil fuels).
When people talk about greenhouse gases, you probably imagine and methane, two of the most problematic emissions pumped out by human industrial activity. However, natural water vapor is actually the most abundant greenhouse gas and traps a huge amount of heat in the Earth’s atmosphere.
In a new study, scientists at the NOAA Chemical Sciences Laboratory question whether it would be hypothetically possible to cool the Earth by dehydrating the stratosphere, the upper part of the atmosphere, to remove this heat-trapping water vapor.
One way to do this would be spraying parts of the atmosphere with small particles, which provide a surface for the moisture to condense into ice crystals and eventually cause rain, thereby draining the atmosphere of water vapor.
“Pure water vapor doesn’t readily form ice crystals. It helps to have a seed, a dust particle for example, for ice to form around,” Joshua Schwarz, lead study author and a research physicist at the National Oceanic and Atmospheric Administration (NOAA) Chemical Sciences Laboratory, said in a .
A lot of water vapor enters the atmosphere around the tropics where warm temperatures encourage evaporation. Armed with this knowledge, the team argues that a key target for the plan could be the Western Pacific Cold Point (WCP), an Australia-sized region that acts as a major gateway for water vapor that is carried into the stratosphere.
Using observational data and computer models, the scientists worked out how dispersing ice nuclei into the supersaturated air of the WCP would have an impact on the wider climate.
They concluded that the novel geoengineering scheme could help to cool the planet, although not enough to counteract the mammoth impact of human-made greenhouse gas emissions.
“It’s a very small effect,” added Schwarz.
While not enough to mitigate alone, the researchers conclude that this technique could be “valuable as an element within a larger portfolio of climate intervention strategies.”
However, the prospect of solving our planet’s environmental woes using is deeply controversial because meddling with complex systems, like Earth’s climate, can easily . It’s also not addressing the fundamental issue of fossil fuel use, like remedying symptoms without treating the disease.
Given these dangers, a group of scientists have called on governments to on efforts to geoengineer the planet’s climate.
The study is published in .