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A team of chemistry researchers in the United Kingdom has discovered a molecule that could potentially halt global warming and its effects by cleaning the atmosphere of pollutants and producing clouds.
In the 1950s, German chemist Rudolph Criegee postulated the existence of these molecules, which are known as the Criegee biradicals or Criegee intermediates. Criegee biradicals were confirmed only recently because the means to observe had not been developed until now. They are extremely reactive and elusive: once they form, they immediately bond with other chemicals.
The researchers, from the Universities of Manchester and Bristol and the Sandia National Laboratories, accidentally detected the molecule while performing an experiment with a synchrotron, which used light from the Lawrence Berkeley National Laboratory’s Advanced Light Source.
The intense light allowed the researchers to discern the Criegee biradicals’ formation and eliminate those of similarly arranged molecules. Upon detecting them, the team further observed the Criegee biradicals reacting in atmospheric conditions in the synchrotron. They learned that the molecules formed rapidly – faster than imagined – and accelerated in formation when in the presence of pollutants.
“Criegee radicals have been impossible to measure until this work carried out at the Advanced Light Source,” says Dr. Carl Percival, Reader in Atmospheric Chemistry at the University of Manchester and co-author of the team’s paper, in the University of Manchester’s media release. “We have been able to quantify how fast Criegee radicals react for the first time.”
Criegee biradicals oxidize pollutants such as nitrogen dioxide and sulphur dioxide into nitrates and sulfates. These compounds initiate the development of aerosols, tiny particles that deflect solar radiation into space. Aerosol formation ultimately leads to cloud formation, which cools the Earth by blocking sunlight.
These reactions can occur anytime. According to Dr. Percival, “The main source of these Criegee biradicals does not depend on sunlight and so these processes take place throughout the day and night.”
“But the fact is that these [intermediates] haven’t been studied before,” George Marston tells LiveScience.com, “so it’s difficult to know what you would really expect.” Marston, who did not partake in the research, is a chemist at the University of Reading in the United Kingdom.
The Criegee biradicals have not yet been observed in action in the atmosphere, so the idea of the molecules controlling the Earth’s climate remains hypothetical. Initiating the formation of Criegee biradicals and controlling their reactions at such a large scale would be a difficult task for scientists to undertake.
Furthermore, the geoengingeering project may backfire; the atmosphere is still complex and not well understood. “This is very much the beginning of a much more extensive systematic study,” Marston adds.