12/7/2023 0 Comments Chlorine gas oxygen not includedIn response, global ozone depletion has stabilized, and initial signs of recovery of the ozone layer are being observed. The replacement of CFCs has occurred in two phases: first via the use of hydrochlorofluorocarbons (HCFCs) that cause considerably less damage to the ozone layer compared to CFCs, and second by the introduction of hydrofluorocarbons (HFCs) that do not deplete ozone. As a result of the broad compliance with the Montreal Protocol and subsequent amendments and adjustments as well as industry’s development and deployment of “ozone-friendly” substitutes to replace CFCs, the total global accumulation of ODSs in the atmosphere has begun to decrease. In 1987, this framework led to the Montreal Protocol on Substances that Deplete the Ozone Layer (the Montreal Protocol), an international treaty designed to control the production and consumption of CFCs and other ODSs. The Vienna Convention provided a framework through which nations agreed to take appropriate measures to protect human health and the environment from activities that harm the ozone layer, including cooperation on systematic observations, research and exchange of information. In 1985, the world’s governments adopted the Vienna Convention for the Protection of the Ozone Layer in response to the prospect of increasing ozone depletion. Most importantly, we know that if the most potent ODSs were to continue to be emitted and increase in the atmosphere, the result would be ever greater depletion of the ozone layer. With this foundation, we know that ozone depletion has been occurring and we understand why. The work of many scientists throughout the world has built a broad and solid scientific understanding of the ozone-depletion process. A thinning of the ozone layer also has been observed over other regions of the globe, such as the Arctic and northern and southern midlatitudes. The loss in this region is commonly called the “ozone hole” because the ozone depletion is solarge and localized. The most severe ozone loss, unexpected at the time of discovery, was found to be recurring each springtime over Antarctica. Computer models of the atmosphere employing this information were used to simulate how much ozone depletion was already occurring and to predict how much more might occur in the future.īy the mid-1980s observations of the ozone layer showed that depletion was indeed occurring. Measurements in the laboratory and in the atmosphere characterized the chemical reactions that were involved in ozone destruction. These trends were linked to growing production and use of CFCs and other ODSs for spray can propellants, refrigeration and air conditioning, foam blowing, industrial cleaning, and other applications. Monitoring stations showed that the abundances of gases that are ozone-depleting substances (ODSs) 1, such as chlorofluorocarbons (CFCs), were steadily increasing in the atmosphere. The resulting increase in ultraviolet radiation at Earth’s surface would increase incidents of skin cancer and eye cataracts, suppress the immune systems of humans, and also adversely affect agriculture as well as terrestrial and oceanic ecosystems.įollowing the discovery of this environmental issue, researchers sought a better understanding of this threat to the ozone layer. In the mid-1970s scientists discovered that some human-produced chemicals could lead to depletion of the stratospheric ozone layer. About 90% of atmospheric ozone is contained in the stratospheric “ozone layer”,which shields Earth’s surface from harmful ultraviolet radiation emitted by the Sun. Most of Earth’s ozone resides in the stratosphere, the layer of the atmosphere that is more than 10 kilometers (6 miles) above the surface. Nevertheless, ozone is vital to human well-being as well as agricultural and ecosystem sustainability. Ozone is present only in small amounts in the atmosphere.
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