I call for that same spirit of common cause and, especially, greater leadership as we strive to implement the Paris Agreement on climate change and mobilize the ambitious climate action we so urgently need at this time." UN Secretary-General António Guterres
The ozone layer, a fragile shield of gas, protects the Earth from the harmful portion of the rays of the sun, thus helping preserve life on the planet.
The International Day for the Preservation of the Ozone Layer commemorates human efforts to protect the atmospheric layer that shields all life forms on Earth from the Sun’s harmful ultraviolet rays. Observed on 16 September each year, the occasion also presents an opportunity to educate the public about the ozone layer, its ‘hole’ over Antarctica, and the vital role that monitoring services play in assessing the dangers posed by ozone depletion.
The Copernicus Atmosphere Monitoring Service (CAMS), implemented by ECMWF, is a major provider of data used by policy makers to ensure that the Montreal Protocol on Substances that Deplete the Ozone Layer – an international treaty signed on this day in 1987 – is successfully executed. By supplying information on the amounts of ozone in the stratosphere, where about 90 percent of ozone is found, CAMS data helps to quantify the effects of the treaty, which phases out almost 100 ozone-depleting chemicals, such as chlorofluorocarbons (CFCs).
The Montreal Protocol and its amendments have had huge success in cutting as much as 98 percent of the world’s consumption of chlorofluorocarbons, hydrochlorofluorocarbons, halons and other ozone-depleting chemicals. As a result of the Protocol, the first universally ratified treaty in United Nations history, the ozone layer is slowly recovering and the hole has stopped growing. However, ozone-depleting substances can remain in the stratosphere for up to a century, so scientists estimate that the ozone layer will not return to pre-1970s levels until 2060, assuming that nations continue to comply with the treaty.
“Monitoring is very important because although we know the basic principles on how the Montreal Protocol should affect ozone in the stratosphere, there are lots of other factors to consider,” says Johannes Flemming, CAMS Principal Scientist. “We have to see if a larger ozone hole in one particular year means the Montreal Protocol is not working or if the anomaly is part of the natural variability. It may also be influenced by stratospheric temperature trends from climate change or the varying presence of stratospheric aerosol injected by major volcanic eruptions.”
The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson. In 1976, atmospheric research revealed that the ozone layer was being depleted by chemicals released by industry, mainly chlorofluorocarbons. Concerns that increased UV radiation due to ozone depletion threatened life on Earth, including increased skin cancer in humans and other ecological problems, led to bans on the chemicals, and the latest evidence is that ozone depletion has slowed or stopped.
September 16 was designated by the United Nations General Assembly as the International Day for the Preservation of the Ozone Layer. This designation had been made on December 19, 2000, in commemoration of the date, in 1987, on which nations signed the Montreal Protocol on Substances that Deplete the Ozone Layer.