Is drying the stratosphere possible? This is the proposed new way to combat climate change
In a recently published study, researchers suggest a new way to help combat climate change: drying out the upper atmosphere. See more information here.
Much has been discussed about the actions necessary to combat climate change. In fact, this is one of the UN Sustainable Development Goals (SDGs): the 13º, entitled "Action against Global Climate Change, which proposes the adoption of urgent measures to combat climate change and its impacts.
The stratosphere is the atmospheric layer that is above the troposphere, extending approximately between 12 km and 50 km above the earth's surface, and the temperature increases with altitude. It is in this layer that ozone is concentrated, so it is heated.
In this sense, a study recently published in the journal Science Advances, developed by researchers from the Chemical Sciences Laboratory (CSL) of NOAA, suggests a new idea to help combat climate change: drying the high atmosphere (stratosphere) of the Earth. That's exactly what you read! See below what that would be like...
"Dehydrating" the stratosphere for climatic benefits
The researchers' idea is to remove water vapour from the stratosphere, the layer in which it acts as a greenhouse gas (GHG) and is very abundant, which would help mitigate climate change.
By injecting particles into areas "where it is important", the stratosphere would "dehydrate" gradually and this would compensate for a seventy-sth (1/70) of the warming caused by climate change.
The researchers named the idea as "intentional stratospheric dehydration".The mechanism behind this concept is the directed injection of small particles known as ice cores into the stratosphere, using high-altitude aircraft. These particles would be bismuth triiodide (BiI3), a material that is also being considered for other climate engineering: the thinning of cirrus clouds.
According to Joshua Schwarz, main author of the work, if these particles could be sown in the stratosphere, part of the water vapour would condense into ice and fall, and more infrared radiation would come out into space, thus removing excess steam and drying (at least partially) the stratosphere. According to the study, the removal of about 3% of water vapour would have a global effect.
However, this idea would only work plausibly after overcoming several technical barriers; "at the moment we do not have a plan or technology to do this," said Schwarz. There are even aircraft capable of reaching the altitudes of the stratosphere, but the idea still needs the development of technologies to inject the nuclei into the layer. And also more research to identify potential risks and unintentional effects.
Scientific skepticism
Some scientists are skeptical. They believe that such an invention by itself makes no sense. The mechanism would have to be repeated regularly to maintain the compensatory cooling effect, and meanwhile, carbon dioxide (CO2) is accumulating in the atmosphere remaining there for a long term.
Although carbon dioxide and methane are the most important greenhouse gases (GHG) in man-made climate change, water vapour remains the most common GHG.
In fact, Schwarz says that this idea would only cool a small part of the atmosphere compared to what CO2 heats. This method would have only a small impact compared to the impact of CO2, since this gas remains a major problem for heating. But Schwarz also makes it clear that "this idea is not a magical solution... it's just an alternative that will do something in the right direction".
However, this remains a controversial topic: "The ethical issues associated with climate manipulation are so great that some forms of geoengineering are simply unacceptable," said Kevin Trenberth, a scientist at the National Center for Atmospheric Research (NCAR).
News reference:
Schwarz, J. P. et al. Considering intentional stratospheric dehydration for climate benefits. Science Advances, v. 10, n. 9, 2024.