Scientists report that chemicals that are not controlled by a United Nations treaty designed to protect the Ozone Layer are contributing to ozone depletion.
Study lead author Dr Ryan Hossaini, from the School of Earth and Environment at the University of Leeds, said: “VSLS can have both natural and industrial sources. Industrial production of VSLS is not controlled by the United Nations Montreal Protocol because historically these chemicals have contributed little to ozone depletion.
“But we have identified now that one of these chemicals is increasing rapidly and, if this increase is allowed to continue, it could offset some of the benefits to the Ozone Layer provided by the Montreal Protocol.”
In the study, the researchers used a 3D computer model of the atmosphere to determine the impact of VSLS on ozone and climate.
Measurements of VSLS in the atmosphere over the past two decades, provided by collaborators from the National Oceanic and Atmospheric Administration (NOAA) in the United States, were also analysed. These measurements revealed a rapid increase in atmospheric concentrations of dichloromethane, a man-made VSLS used in a range of industrial processes.
Study co-author Professor Martyn Chipperfield, from Leeds’ School of Earth and Environment, said: “We need to continue monitoring the atmospheric abundance of these gases and determine their sources. At present, the long-term recovery of the Ozone Layer from the effects of CFCs is still on track, but the presence of increasing dichloromethane will lead to uncertainty in our future predictions of ozone and climate.”
Read more: New ozone-destroying gases on the rise