International Day for the Preservation of the Ozone Layer

The United Nations’ (UN) International Day for the Preservation of the Ozone Layer is celebrated on September 16 every year. This event commemorates the date of the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer in 1987. The theme of 2013 is ‘A healthy atmosphere, the Future We Want’.

Background
In 1987, representatives from 24 countries met in Montreal and announced that it was time to stop destroying the ozone layer. In doing so, these countries committed themselves, via the Montreal Protocol on Substances that Deplete the Ozone Layer, to rid the world of substances that threaten the ozone layer.
Later, on December 19, 1994, the UN General Assembly vide a resolution 49/114 proclaimed September 16 to be the International Day for the Preservation of the Ozone Layer, commemorating the date when the Montreal Protocol on Substances that Deplete the Ozone Layer was signed in 1987. The day was first celebrated on September 16, 1995. It offers an opportunity to focus global attention and action on this vital environmental issue.

Symbols
Many promotional items used for the day feature images of the sun, sky, or earth’s natural environment to represent the ozone’s importance in protecting the environment. Selected winning paintings from the 1998 Children’s Painting Competition, which was part of UNEP’s public awareness campaign at the time, have since been reproduced on posters, calendars, publications, and other material.

What is the Ozone Layer?
The ozone layer is a belt of naturally occurring ozone gas that sits 9.3 to 18.6 miles (15 to 30 kilometres) above Earth and serves as a shield from the harmful ultraviolet B radiation emitted by the sun.

Ozone is a highly reactive molecule that contains three oxygen atoms. It is constantly being formed and broken down in the high atmosphere, 6.2 to 31 miles (10 to 50 kilometres) above Earth, in the region called the stratosphere.

Today, there is widespread concern that the ozone layer is deteriorating due to the release of pollution containing the chemicals chlorine and bromine. Such deterioration allows large amounts of ultraviolet B rays to reach Earth, which can cause skin cancer and cataracts in humans, and harm animals as well.

Extra ultraviolet B radiation reaching Earth also inhibits the reproductive cycle of phytoplankton, single-celled organisms such as algae that make up the bottom rung of the food chain. Biologists fear that reductions in phytoplankton populations will, in turn, lower the populations of other animals. Researchers also have documented changes in the reproductive rates of young fish, shrimp, and crabs as well as frogs and salamanders exposed to excess ultraviolet B.

Chlorofluorocarbons (CFCs), chemicals found mainly in spray aerosols heavily used by industrialized nations for much of the past 50 years, are the primary culprits in ozone layer breakdown. When CFCs reach the upper atmosphere, they are exposed to ultraviolet rays which cause them to break down into substances that include chlorine. The chlorine reacts with the oxygen atoms in ozone and rips apart the ozone molecule.

One atom of chlorine can destroy more than a hundred thousand ozone molecules, according to the US Environmental Protection Agency.

The ozone layer above the Antarctic has been particularly impacted by pollution since the mid-1980s. This region’s low temperatures speed up the conversion of CFCs to chlorine. In the southern spring and summer, when the sun shines for long periods of the day, chlorine reacts with ultraviolet rays, destroying ozone on a massive scale, up to 65 per cent. This is what some people erroneously refer to as the “ozone hole.” In other regions, the ozone layer has deteriorated by about 20 per cent.

About 90 per cent of CFCs currently in the atmosphere were emitted by industrialized countries in the Northern Hemisphere, including the United States and Europe. These countries banned CFCs by 1996, and the amount of chlorine in the atmosphere is falling now. But scientists estimate it will take another 50 years for chlorine levels to return to their natural levels.

Significance of Ozone Day
The commemoration of the International Day for the Preservation of the Ozone Layer around the world offers an opportunity to focus attention and action at the global, regional and national levels on the protection of the ozone layer. All Member States devote this special day to promotion, at the national level, of concrete activities in accordance with the objectives and goals of the Montreal Protocol and its Amendment.

This international day also affords an opportunity to celebrate the significant benefits brought about by the Montreal Protocol. Specifically, by reducing the production and import of ozone-depleting substances by over 98 per cent, the parties have put the ozone layer firmly on the path to recovery and helped to ensure that present and future generations will reap the benefits of the parties