The Threat to the Ozone Layer
During the 1970s, scientists studying Earth’s atmosphere found that ozone was vanishing from its upper levels. By 1985, a very large area above Antarctica was almost entirely free of the gas. The cause of this depletion was quickly identified as chlorofluorocarbon compounds, or CFCs for short – a family of chemicals then commonly used in refrigerators, freezers and air conditioners. CFCs rise into the upper atmosphere, react with the ozone there, and destroy it. But besides CFCs, there was another offender: methyl bromide, a pesticide used to fumigate soil and many agricultural products. At the time this was discovered, methyl bromide pesticides were widely used in the Sri Lankan tea industry, on estates as well as in warehouses, aboard ships in and other places where tea was stored or transported. No-one suspected the environmental damage these pesticides were causing, 10-15km up in the sky! But given the size and geographical spread of the Sri Lankan tea industry, its use of methyl bromide posed a real threat to the ozone layer.