GREEN HOUSE EFFECT AND OZONE DEPLETION

Green house effect and ozone depletion

1. GREEN HOUSE EFFECT AND OZONE DEPLETION Presented by M.Shravan Kumar Reddy. M.Sc. Agronomy 1 st year RAM /2016-03 .

2. When we discuss about the Green house effect we need to know the following things . What is Green House Effect ?& process. What are the causes of green house effect ? What are the consequences of green house effect? Can we control the green house effect?

3. GREEN HOUSE EFFECT The greenhouse effect is a natural process that warms the Earth’s surface . When the Sun’s energy reaches the Earth’s atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases. The   greenhouse effect   is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without its atmosphere

4. HOW GHE IS USEFUL??? Without green house effect we can not survive in the planet earth bacause ,, The absorbed energy warms the atmosphere and the surface of the Earth . This process maintains the Earth’s temperature at around 33 degrees Celsius warmer than it would otherwise be, allowing life on Earth to exist .

5. Without greenhouse gases, the average temperature of  Earth's surface  would be about −18 °C (0 °F), rather than the present average of 15 °C Green house gases Greenhouse gases include carbon dioxide, methane, nitrous oxide, ozone and some artificial chemicals such as chlorofluorocarbons (CFCs). .

6. Greenhouse effect Step 1:  Solar radiation reaches the Earth's atmosphere - some of this is reflected back into space. Step 2:  The rest of the sun's energy is absorbed by the land and the oceans, heating the Earth. Step 3:  Heat radiates from Earth towards space. Step 4:  Some of this heat is trapped by greenhouse gases in the atmosphere, keeping the Earth warm enough to sustain life. Step 5:  Human activities such as burning fossil fuels, agriculture and land clearing are increasing the amount of greenhouse gases released into the atmosphere. Step 6:  This is trapping extra heat, and causing the Earth's temperature to rise.

7. Causes of green house effect Green House gases : Includes CO 2 ,CH4,O3, NO ,NO2 and CFC etc…. Though green house gases are helpful to maintain atmosphere temparature but increased amounts over optimum is not at al usefull … Contribution of clouds to Earth's greenhouse effect The major non-gas contributor to Earth's greenhouse effect,  clouds , also absorb and emit infrared radiation and thus have an effect on radiative properties of the greenhouse gases.

8. Compound   Formula   Concentration in atmosphere [  ( ppm ) Contribution (%) Water vapor  and clouds H2O 10–50,000 36–72%    Carbon dioxide CO 2 ~400 9–26% Methane CH4 ~1.8 4–9%    Ozone O3 2–8 3–7%   

9. Anthropogenic factors : This includes the man made processes like B urning of  fossil fuels  and  deforestation  , paddy cultivation , use of GH gases like CFC and halons in refrigiration and fire suppression systems , and indiscriminate use of fertilizers mostly N fertilizers ,etc…leads to increased GHE.

10. Enhanced green house effect The problem we now face is that human activities – particularly burning fossil fuels (coal, oil and natural gas), agriculture and land clearing – are increasing the concentrations of greenhouse gases. This is the enhanced greenhouse effect, which is contributing to warming of the Earth . Enhanced green house effect lead to GLOBAL WARMING .

11. Consequences of greenhouse-effect The effects due to GHE include : M ore drought and more flooding L ess ice and snow M ore extreme weather incidents R ising sea level .

12. More drought and more flooding When the weather gets warmer , evaporation from both land and sea increases . This can cause drought in areas of the world where the increased evaporation is not compensated for by more precipitation. In some regions of the world this will result in crop failure and famine especially in areas where temperatures are already high. The extra water vapour in the atmosphere will fall again as extra rain , which can cause flooding in other places in the world.

13. Less ice and snow Worldwide, glaciers are shrinking rapidly at present. Ice appears to be melting faster than previously estimated. In areas that are dependent on melt water from mountain areas, this can cause drought and lead to lack of water supply . According to the IPCC, up to a sixth of the world's population lives in areas that will be affected by melt water reduction.

14. snow melting due to GHG

15. More extreme weather incidents The warmer climate will probably cause more heatwaves, more violent rainfall and also an increase in the number and/or severity of storms.

16. Rising sea level S ea level rises because of melting ice and snow and because of the thermal expansion of the sea (water expands when warmed). Areas that are just above sea level now , may become submerged . In countries with large areas of coastal lowland there will be a dual risk of river floods and coastal flooding, which will reduce the area for living and working . The increase in standing water may allow more insects like mosquitoes and diseases spread by insects, such as Lyme’s disease.

17. What evidence is there that the Earth’s climate is changing ? According to IPCC Widespread decreases in glaciers and ice caps have contributed to sea level rise . Increased sea levels : . Since 1961 the average rate has been 1.8 mm per year but since 1993 this has increased to 3.1 mm per yea r Increasing the temparatures over the years passes I t has been estimated that now at present around 2 degrees more temparature due to GHE.

18. Increased amount of water v apour in the atmosphere : This is because of the fact that warmer air can hold more water than colder air. This is in turn increase in air temparature is due to GHE .

19. CAN WE CONTROL GREEN HOUSE EFFECT

20. Ways to Reduce Greenhouse Gases Reduce, Reuse, Recycle Buying products with minimal packaging will help to reduce waste. By recycling half of your household waste, you can save 2,400 pounds of carbon dioxide annually . Use Less Heat and Air Conditioning Adding insulation to your walls and installing weather stripping or caulking around doors and windows can lower your heating costs more than 25 percent, by reducing the amount of energy you need to heat and cool your home.

21. Replace Your Light Bulbs Wherever practical, replace regular light bulbs with compact florescent light (CFL) bulbs. Drive Less and Drive Smart Less driving means fewer emissions. Besides saving gasoline, walking and biking are great forms of exercise . . Buy Energy-Efficient Products Home appliances now come in a range of energy-efficient models, and compact florescent bulbs are designed to provide more natural-looking light while using far less energy than standard light bulbs .

22. Use Less Hot Water Set your water heater at 120 degrees to save energy, and wrap it in an insulating blanket if it is more than 15 years old. Buy low-flow showerheads to save hot water and about 350 pounds of carbon dioxide yearly. Use the "Off" Switch Save electricity and reduce global warming by turning off lights when you leave a room, And remember to turn off your television, stereo and computer when you're not using them. turn off the water when you’re not using it. While brushing your teeth, shampooing the dog or washing your car, turn off the water until you actually need it for rinsing. Plant a Tree             Trees absorb carbon dioxide and give off oxygen. A single tree will absorb approximately one ton of carbon dioxide during its life

23. Encourage Others to Conserve This is last but not least ….this is most important .because we can control the green house effect all in the society put their efforts ..its not possible to control by an individual S o s hare information about recycling and energy conservation with your friends, neighbors and co-workers, and take opportunities to encourage public officials to establish programs and policies that are good for the environment .

24. OZONE DEPLETION

25. What is Ozone Depletion? ozone layer depletion, is simply the wearing out (reduction) of the amount of ozone in the stratosphere

26. Why Ozone Layer is Necessary? It is necessary because An essential property of ozone molecule is its ability to block solar radiations of wavelengths less than 290 nanometers from reaching Earth’s surface. In this process, it also absorbs ultraviolet radiations that are dangerous for most living beings . UV radiation could injure or kill life on Earth.  For humans, excessive exposure to ultraviolet radiation leads to higher risks of cancer (especially skin cancer) and cataracts. It is calculated that every 1 percent decrease in ozone layer results in a 2-5 percent increase in the occurrence of skin cancer . Other ill-effects of the reduction of protective ozone layer include – increase in the incidence of cataracts, sunburns and suppression of the immune system.

27. The Impacts of Ozone Depletion Harm to human health : More skin cancers, sunburns and premature aging of the skin. More cataracts, blindness and other eye diseases: UV radiation can damage several parts of the eye, including the lens, cornea, retina and conjunctiva. Weakening of the human immune system (immunosuppression). Early findings suggest that too much UV radiation can suppress the human immune system, which may play a role in the development of skin cancer.

28. Adverse impacts on agriculture, forestry and natural ecosystems : Most of the crops are senisitive to increased UV, resulting in reduced growth, photosynthesis and flowering. These species include wheat, rice, barley, oats, corn, soybeans, peas, tomatoes, cucumbers, cauliflower, broccoli and carrots. Only a few commercially important trees have been tested for UV (UV-B) sensitivity, but early results suggest that plant growth, especially in seedlings, is harmed by more intense UV radiation.

29. Damage to marine life : In particular, plankton (tiny organisms in the surface layer of oceans) are threatened by increased UV radiation. Plankton are the first vital step in aquatic food chains. Loss of biodiversity in our oceans, rivers and lakes could reduce fish yields for commercial and sport fisheries.

30. Animals : In domestic animals, UV overexposure may cause eye and skin cancers.   Materials : Wood , plastic, rubber, fabrics and many construction materials are degraded by UV radiation. The economic impact of replacing and/or protecting materials could be significant.

31. Causes of depletion of ozone layer Natural causes of depletion of ozone layer :  Ozone layer has been found to be affected by certain natural phenomena such as Sun-spots and stratospheric winds. This is not more than 1-2 %   Man-made causes of depletion of ozone layer :  The main cause for the depletion is excessive release of chlorine and bromine from man-made compounds such as chlorofluorocarbons (CFCs ), halons , CH 3 CCl 3  (Methyl chloroform), CCl 4  (Carbon tetrachloride), HCFCs ,HBFCs and methyl bromide are found to have direct impact on the depletion of the ozone layer. These are categorized as ozone-depleting substances (ODS). 

32. Main Ozone Depleting Substances (OCD) Chlorofluorocarbons : Account for more than 80% of ozone depletion. Used in freezers, air cooling component, dry-cleaning agents, hospital sterilants . Methyl Chloroform : Used for vapour degreasing, some aerosols, cold cleaning, adhesives and chemical processing. Hydrochlorofluorocarbons : Substitutes for CFC’s but still play a vital role in ozone depletion . Carbon Tetrachloride: Mainly used in fire extinguisher

33. Chlorofluorocarbons are released into the atmosphere due to : Cleaning Agents Coolants in refrigerators Packing material Air conditioning Aerosol spray cans etc

34. Measures to Protect Ozone Layer Depletion : The use of plastic should be banned in the country. The production and use of CFCs should be banned. The use of CFCs in aerosol, spray cans, egg crates etc. should be banned and their substitutes should be used. New technologies should be adopted to recapture the CFCs released from the air-conditioners and refrigerators .   Limit private vehicle driving

35. Use eco-friendly household cleaning products Reduce the use of pesticides Developing stringent regulations for rocket launches Banning the use of dangerous nitrous oxide .