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Slide 2 zone Depletion Slide 3 Ozone Depletion is a term describing two distinct but related phenomena observed since late 1970s. These two phenomena include decrease of 4 % per decade in the total volume of ozone in Earths stratosphere and much larger decrease of stratospheric ozone over Earths polar regions during springtime. Slide 4 Since ozone layer absorbs most of UV radiation comes to the Earth, the depletion of ozone in stratosphere will let the UV radiation directly hits the surface of the Earth, which lead to many biological problems in organisms. Slide 5 1996 Even though Montreal Protocol banned chlorofluorocarbons (CFCs), household refrigerators and freezers, air conditioners, and cars, manufactured before 1996, still contain a lot of CFCs as a cooling chemical, which is very responsible for stratospheric ozone depletion. Slide 6 So, if you abandon those items without any treatment, ozone-depleting chemicals from them will directly released into the atmosphere. Cl C F C F C F C F Slide 7 UV-ray Sun Cl C F CFC When CFC is released from the surface of the Earth and transported into stratosphere, CFC gains energy from ultraviolet radiation. Then, it releases chlorine (Cl) atom from it Slide 8 Cl O O O O 3 (Ozone)O 2 (Oxygen) That Cl atom combines with ozone molecule (O3). After that, Cl atom breaks O3 molecule into O and O2 Slide 9 Cl O O O 2 (Oxygen) O atom attaches with other O atom in the air in order to form O2 molecule. Slide 10 Cl O O O O 3 (Ozone)O 2 (Oxygen) The same Cl atom goes through the same reactions with other O3, and this causes chain reactions of ozone depletion in stratosphere. One CFC molecule can destroy between 10,000 and 1,000,000 ozone molecules. Slide 11 Cl O O O 2 (Oxygen) Slide 12 Cl O O O O 3 (Ozone)O 2 (Oxygen) Slide 13 Cl O O O 2 (Oxygen) Slide 14 Stratospheric ozone layer is responsible for preventing ultraviolet (UV) radiation in sunlight from reaching Earth. Since ultraviolet radiation is harmful to both plants and animals, life on Earth could probably not survive without the ozone layer UV Slide 15 Therefore, if people keep ignoring this issue, then the size of the ozone hole will get bigger and bigger, and it will let UVB radiation directly hits the Earths surface, which will lead to many biological consequences such as increases in skin cancer, cataracts, damage to plants, and reduction of plankton populations in the oceans photic zone. Slide 16 There are many environmental NGOs working on this issue. In 1970s, UNEP proposed that appropriate Non-Governmental Organizations (NGOs), of both the environmental and industry based types, be involved in the negotiation process (Gillespie, 263). Slide 17 For example, the Non-Governmental Organization (NGO) Network of the Global Environment Facility (GEF), now known as the GEF-NGO Network, spent about $117 million for the project, and they have a co-financing of $182 million between 1991 and 2004. Slide 18 You can help these NGOs to make the size of the ozone hole smaller by donating little money, or you can get rid of your old refrigerator, old air conditioner, and old car properly through recycling. Slide 19 Slide 20 Slide 21