Earth System Trend
The ozone layer high in the upper atmosphere protects life on Earth from the sun’s ultraviolet radiation. Manmade chemicals called chlorofluorocarbons destroy ozone. In 1985, researchers made one of the most important discoveries in the history of science – a giant hole had appeared in the ozone layer above Antarctica. Nations agreed to ban these harmful chemicals. Recently, the ozone hole stopped expanding and there may even be signs of a recovery.
Graph Caption: Maximum percentage total column ozone decline (two-year moving average) over Halley, Antarctica, during October, using 305 DU, the average October total column ozone for the first decade of measurements, as a baseline.
Source: Data provided by J. D. Shanklin, British Antarctic Survey, UK. www.antarctica.ac.uk/met/jds/ozone/index.html#data