When you say the term “ozone layer,” most people will claim to be familiar with the concept, but likely have some difficulty in giving any details on what exactly it is. The ozone layer is a portion of the Earth’s upper atmosphere that contains high amounts of ozone molecules. Ozone is a molecule comprised of three oxygen atoms. In contrast normal oxygen gas that’s part of the air we breathe is composed of molec ules with two oxygen atoms. The extra oxygen atom allows ozone layer in the stratosphere to protect life on Earth by filtering out much of the ultraviolet light that would otherwise harm humans and other animals. The Ozone Layer is Under Threat. Unfortunately, human activity can affect (and has affected) the ozone layer. Certain chemical compounds such as nitric oxide, nitrous oxide and chlorine can deplete the concentration of ozone in the upper atmosphere. While there are naturally occurring sources of each of these ozone depleting compounds, most of the damage is done by man-made sources. A particularly damaging class of man-made compounds is known as chlorofluorocarbons. These compounds rise to the upper atmosphere where they react with ultraviolet light in such a way as to permanently break down ozone molecules. Many of us remember back to the late 1970s when the United States and several other countries enacted bans on chlorofluorocarbons in aerosol sprays. More countries have come on board with additional chlorofluorocarbon bans, and the effects have already been shown to have slowed the depletion of the ozone layer. The risks to the ozone layer continue to be present, however, because there are still a number of countries that have not banned the use of chlorofluorocarbons. In addition, one of the primary replacements for chlorofluorocarbons – hydrochlorofluorocarbons – also have a negative (though lesser) effect on the ozone layer, so those compounds are also in the process of being removed from general use. Greenhouse Effects of Ozone. When ozone is present in the lower levels of the atmosphere, it can act as a so-called “greenhouse gas.” A greenhouse gas is any gas in the lower atmosphere that tends to absorb and retain any heat that radiates from the Earth’s surface. This slowly raises the base temperatures of everything on Earth. In the long term, climate changes brought about by an increase in greenhouse gases such as ozone could fundamentally alter the Earth. Immediate effects might include a massive dying off of many ocean creatures (raising the ocean temperature just a few degrees would be catastrophic) as well as an increase in significant and damaging weather events. In the longer term, the greenhouse effect could be responsible for melting polar ice caps and slightly raising the level of our oceans. Because so much of the world’s population lives near ocean coasts, even a slight rise in water levels could destroy some of the world’s most populated cities. Changing climatic patterns would also change the areas of the world that are suitable for agricultural uses. Helping the Ozone Layer. In order to do your part to help the ozone layer, it’s important to avoid any consumer product that contains hydrochlorofluorocarbons. In addition, consider making a financial donation to a group or charity that is working to remove the remaining chlorofluorocarbon and hydrochlorofluorocarbons product from the environment.