A new atmospheric molecule long suspected to exist has finally been observed and analysed by scientists.
The Criegee biradicals have been implicated in several climate processes, specifically the likelihood that their existence was linked to the process by which pollutants such as nitrogen and sulphur dioxide are turned into nitrates and sulphates.
In other words, Criegee biradicals play a part in controlling the climate.
Using custom-designed instruments and a synchotron, the scientists found that Criegee biradicals play a role in removing pollutants from the atmosphere as well as influencing the climate by accelerating the production of sulphuric acid, which in turn triggers cloud formation which block sunlight and cool our planet.
‘We’ve known for a long time that Criegee biradicals are involved in several important reactions in atmospheric chemistry, but nobody’s been able to observe them directly until now,’ says Dr Carl Percival of the University of Manchester, one of the report’s authors.
This new production of sulphuric acid comes in alongside a previously known method, volcanoes. When volcanoes erupt they eject massive amounts of sulphur dioxide into the atmosphere which, scientists have observed, produces a cooling effect as the sulphur dioxide turns into sulphates and eventually into sulphuric acid.
‘This new source of atmospheric sulphates is at least as important as the one we knew about already, and in some cases it can dominate,’ Percival explains. As a result, climate models will most likely need to be updated to include this new discovery.
‘A significant ingredient required for the production of these Criegee biradicals comes from chemicals released quite naturally by plants,’ notes Professor Dudley Shallcross of the University of Bristol, another of the paper’s authors. ‘So natural ecosystems could be playing a significant role in offsetting global warming.’