1 / 11

The ozone hole over Antarctic was discovered in 1985

The Ozone Hole. The ozone hole over Antarctic was discovered in 1985. Chlorine molecules are now thought to be mainly responsible for its destruction. Where does this chlorine come from? Manmade chemical called CFC’s. CFCl 3 is an example of a CFC.

ban
Télécharger la présentation

The ozone hole over Antarctic was discovered in 1985

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Ozone Hole The ozone hole over Antarctic was discovered in 1985 Chlorine molecules are now thought to be mainly responsible for its destruction. • Where does this chlorine come from? • Manmade chemical called CFC’s CFCl3 is an example of a CFC.

  2. This is a substance that speeds up a reaction without being consumed. The Catalyst The breakdown of ozone, which is catalyzed by chlorine. This happens inside the Polar vortex on ice crystals Cl(g) + O3 (g)  ClO (g) + O2 (g) O (g) + ClO (g) Cl(g) + O2 (g) In a chemical reaction, the catalyst is not used up. Here the chlorine is free again to react with more ozone molecules. Sum: Cl + O3 +O + ClO ClO + O2 +Cl + O2 O3 +O  2O2

  3. While CFC’s and other substances are destroying stratospheric ozone all over the world, the most dramatic destruction is over Antarctica during the Southern hemisphere spring. 1. Polar Vortex starts each winter (150 mph winds circling the pole) 2. Polar Vortex keeps air above Antarctica in stratosphere from mixing with aif from elsewhere 3. Chemical reactions unique to extremely cold air occur inside the vortex

  4. How Ozone is destroyed • June: As winter begins vortex forms and temperatures drop • July/August: As temperature fall below -108F clouds form from water vapor and nitric acid. Falling snow removes nitrogen which form chlorine reservoirs. Chemical reactions take place on the clouds ice crystals which won’t take place in air, free chlorine atoms are formed • September:Temperatures warm up evaporating the clouds. The Chlorine starts to destroy ozone. • October: low levels of ozone are detected. • November: Vortex breaks down spreading ozone poor air over southern hemisphere.

  5. Ozone in the Atmosphere Ozone is concentrated in the stratosphere. It is responsible for blocking most UV radiation from the sun.

  6. Global Carbon Emissions

  7. Affects of UV radiation:

  8. Global Air Pollution

  9. Methane hydrate is a white, ice-like compound made up of molecules of methane gas trapped inside cages of frozen water. A possible source of energy in the future, since 1970 they have been discovered all round the world. One concern is that methane escaping from disturbed deposits will increase global warming. Methane acts a greenhouse gas and can last in the atmosphere for up to 10 years. It can also react with free oxy to form carbon dioxide.

  10. Contributions to global warming by different types of human activities in 1990 Relative contributions to global warming by anthropogenic gases. Contributions to world CO2 production

More Related