As of: March 1, 2024, 4:33 p.m
By: Tanja Banner
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Just like carbon dioxide, water vapor is also a greenhouse gas.
What if you could get some of it out of the stratosphere?
(Symbolic image) © IMAGO/CHROMORANGE
What if one of the most common greenhouse gases could be extracted from the atmosphere?
With this idea, researchers do not mean CO₂.
Munich – Global warming is progressing and scientists are thinking about how to counteract it.
In addition to CO₂-eating microbes or other ways to save or store carbon dioxide, ideas from the field of geoengineering also come up again and again.
A research team led by Joshua Schwarz from the National Oceanic and Atmospheric Administration (NOAA) in the USA has looked into the question of how the Earth's atmosphere could be manipulated to get rid of some greenhouse gases.
In the study, published in the journal
Science Advances
, the research team describes an interesting approach.
However, it is not about carbon dioxide, but about water vapor.
Although carbon dioxide is the most important driver of climate change, water vapor is the most common greenhouse gas.
It is responsible for about half of the Earth's natural greenhouse effect.
This natural greenhouse effect ensures that our planet is habitable.
Geoengineering: Could water vapor be removed from the atmosphere?
Could removing water vapor from the atmosphere also help curb climate change?
Schwarz's research team asked themselves this and got to work.
The concept the team developed is called intentional stratospheric dehydration.
Small particles, known as ice cores, would be released into high-altitude regions of the atmosphere that are very cold and supersaturated with water vapor.
The ice cores are supposed to promote the formation of ice crystals that would otherwise not have formed.
“Pure water vapor does not easily form ice crystals,” explains Schwarz in a statement.
“It is helpful to have a seed, for example a dust particle, around which ice can form.” Some of the water vapor in the air then condenses into ice and falls down - excess water vapor is thus removed from the stratosphere and this at least partially dehydrated.
Western Pacific cold point would be the ideal location for stratosphere drying
The research team identified the Western Pacific Cold Point (WCP), an area in the atmosphere that is about the size of Australia, as a sensible region for such a measure.
This is where the largest amount of water vapor reaches the stratosphere.
“In terms of effectiveness, the western Pacific cold point is the ideal 'sweet spot.'
That’s why we focused on this point,” says Schwarz.
The WCP is cold enough for ice crystals to form there.
The ice cores that would be introduced by humans would simply reinforce an already existing mechanism.
In the study, the research team shows that the approach would work - but only with a “very small effect,” as Schwarz emphasizes.
The ISD alone would not offset a large portion of the warming caused by CO₂, the researcher said.
However, the scientist believes that the method could be of interest as an element of several climate intervention strategies.
He is certain that research work like that of his team helps “to distinguish the possible from the impossible.”
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