b) Statistics 1984: British Antarctic Survey scientists discovered ozone levels at Antarctica dropped to 10% below normal (Gaille, 2015) Studies between 1974-1978 showed ozone layer would be depleted by 7% overall within 60 years if current trends were not stopped. (Gaille, 2015) Numerous experiments shown that CFCs and other widely-used chemicals produce roughly 84% of the chlorine in the stratosphere. (Gaille, 2015) Figure 2 shows how the uses of CFCs for almost 70% of the market Figure 4 shows the estimated consumption of CFCs in 1986 by geographic region. * figures 2 & 4 are from reference (b). Citation : (Tolba & El-Kholy, 1992) c) Related Laws and Regulations Established by UNEP in the 1970s, the Montreal Protocol was introduced. (Tolba & El-Kholy, 1992) international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion. In 2009, the Vienna Convention and the Montreal Protocol became the first treaties in the history of the United Nations to achieve universal ratification. (Protecting The Ozone Layer While Also Prevent Climate Change, 2017). Other protocols : The Clean Air Act- designed to curb four major threats to the environment in America, including ozone depletion. (The Clean Air-Act, 2017) The Ozone Layer Protection Regulations 1996- contain the rules relating to specific substances. Most of the controls are on importing bulk substances. The Ozone Layer Protection Act - lays down the broad controls for ozone-depleting substances. Figure 1: Timeline for the Montreal Protocol Reference: (a) Gaille, B. (2015, August 11). 47 Curious Ozone Layer Depletion Statistics. Retrieved May 27, 2017, from http://brandongaille.com/47-curious-ozone-layer-depletion-statistics/ (b) Tolba, M. K., & El-Kholy, O. A. (1992). Ozone depletion. The World Environment 1972– 1992, 33-59. (c) THE MONTREAL PROTOCOL ON SUBSTANCES THAT DEPLETE THE OZONE LAYER. (n.d.). Retrieved May 27, 2017, from http://ozone.unep.org/en/treaties-anddecisions/montreal-protocol-substances-deplete-ozone-layer (d) Protecting the ozone layer while also preventing climate change. (2017, January 17). Retrieved May 27, 2017, from https://www.eea.europa.eu/themes/climate/ozone-depletingsubstances-and-climate-change/protecting-the-ozone-layer-while (e) The Clean Air Act - Highlights of the 1990 Amendments. (2017, January 03). Retrieved May 27, 2017, from https://www.epa.gov/clean-air-act-overview/clean-air-act-highlights-1990amendments (f) Ozone Layer Protection Act 1996 and Ozone Layer Protection Regulations 1996. (n.d.). Retrieved May 27, 2017, from http://www.mfe.govt.nz/more/acts-and-regulations/ozonelayer-protection-act-1996-and-ozone-layer-protection-regulations
