Over the last two decades, scientists have been keeping a close eye on the atmospheric concentration of a hydrofluorocarbon (HFC) gas, known as HFC-23.
This gas has very few industrial applications. However, levels have been soaring because it is vented to the atmosphere during the production of another chemical widely used in cooling systems in developing countries.
Scientists are concerned, because HFC-23 is a very potent greenhouse gas, with one tonne of its emissions being equivalent to the release of more than 12,000 tonnes of carbon dioxide.