Global warming


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A short description about global warming, It's causes, effects and it's control.

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Global warming

  1. 1. IndexIntroductionHistoryGreen house gasesGlobal Warming ImpactsControl
  2. 2. Global WarmingAn average increase in the temperature of the atmosphere near the Earth’s surface and in the troposphere, which can contribute to changes in global climate patterns
  3. 3. • Since the late 1800’s, the global average temperature has increased about 0.7 to 1.4 degrees.• The concentration of green house gases in the atmosphere were artificially raised by humans since past 250 years.
  4. 4. Green house effect: How does it workThe greenhouse effect insulates earth, resulting in the mild temperatures at the earths surface that have allowed life to flourish.The greenhouse effect is absolutely vital to allowing life, as we know it to survive on earth. Without the greenhouse effect, earth would be a cold planet, with a mean surface temperature well below freezing.
  5. 5. Main Warming Mechanism: The Greenhouse EffectOur earth receives most of its energy in the form of radiation from the sunThe incoming solar energy (Ultra Violet UV) has a very short wavelength and passes through the atmospheric gases unaffected to reach the earth surfaceThe earth surface absorbs the solar energy and releases it back to the atmosphere at a different wavelength as infrared (IR) radiation, some of which goes back into space
  6. 6. Some of the IR radiation emitted by the earth is absorbed by greenhouse gases in the atmosphere.These gases absorb the infrared radiation emitted by the earth and re-radiate the energy as heat back towards the earth causing a warming known as the greenhouse effect.
  7. 7. Present Day Climate Change:In the history of earth, climate change happened many times.Ones more in the history of the earth, the climate is changing.There is however several differences between past changes in the climate and what we are observing today:
  8. 8.  - Present climate change is occurring very rapidly as opposed to past climate changes which usually occurs over millions of years (rapid change have occurred in the past but has a result of catastrophic events only e.g. meteorite impact, large volcanic eruptions, sudden feedback) - Present day climate change is not a natural event but a result of human activity - Present day climate change can be prevented as we do know the causes and how to limit the impacts
  9. 9. Brief History Of The Earth Climate: Natural Variability The Earth is a very dynamic planet which has undergone many transformations throughout its history and since its formation 4.6 billion years ago.A succession of geological events and the appearance of life have dramatically influenced the climate of the earth.
  10. 10. HistoryThe field of Paleoclimatology has provided information of climate change in the ancient past, supplementing modern observations of climate.Climate variability usually occurs naturally on the planet over millions of years or suddenly as a result of a catastrophic event (e.g. major volcanic eruptions, meteor impacts).
  11. 11. Few ExamplesMiocene Climate: (23–15 MYA)  The climate during which was warmer than todays climate.Early Cretaceous Climate: (145-65 MYA) The Early Cretaceous was a mild "Ice House" world.Early & Middle Jurassic Climate: (206-144 MYA) Deserts covered what is now the Amazon and Congo rainforests.
  12. 12. HistoryLate Devonian Climate: (360 MYA) Thick coals formed for the first time in the tropical rainforests.Early Permian Climate: (280 MYA) Much of the Southern Hemisphere was covered by ice as glaciers pushed northward.
  13. 13. Example Of A Warmer Climate:Early & Middle Jurassic Climate(206 To 144 Million Years Ago) The Jurassic is an example of a climate era which was much warmer than the climate that we are experiencing today. Much of the Jurassic world was warm and moist, with a greenhouse climate.
  14. 14. Early & Middle Jurassic ClimateThe polar areas were ice-free during this period.The ocean surface stood at a higher level with respect to the continents.Much of the earth was covered in warm and moist tropical forest
  15. 15. Example Of A Colder Climate: TheOrdovician Climate (488 To 444 Million Years Ago)The Ordovician is an example of a past climate which was much colder than the climate that we are experiencing todayGreat Ice Age that gripped the earth at this time.There were even glaciers in what is now the Sahara.About 60% of animal genera became extinct,
  16. 16. Carbon dioxide (CO2)Methane (CH4)Nitrous oxide (N2O)Chlorofluorocarbon (CFC)Water vapour (H2O)
  17. 17. Carbon dioxide : It is generated by the human activities like burning of coal, wood, natural gas.oil etc. It is also released by animals & human beings during the process of respiration. The trees take in the carbon dioxide, therefore deforestation is also an important reason for increase in carbon dioxide. It accounts for 50% of the gases responsible for global warming.
  18. 18. METHANE  Methane accounts for 16% of all gases responsible for global warming .  It is estimated that nearly 30 to 200 million tones of methane is released every year.  The main source of methane is rice field.
  19. 19. NITROUS OXIDE  It is generated due to burning of biomass, agriculture, livestock waste, nitrogen rich fuels.  It accounts for 6% of the gases responsible for global warming.
  20. 20. Chlorofluorocarbon [CFC]  It accounts for nearly 20% of the gases responsible for global warming.  These are non-toxic, nonflammable & highly stable compounds.  They are also used as coolants in compressors of air conditioners & refrigerators.  They are also use in insulators, fire extinguishers, aerosol etc.
  21. 21. Gas Major Source % Contri bution Carbon dioxide Fossil fuel & deforestation 50 Methane Fossil fuel, wood burning. 16 Nitrogen Oxide Wood burning, fertilizer, fossil fuel. 06Chlorofluro carbons & Industries, insulation, refrigeration. 20 other carbon
  22. 22. What’s the proof thatglobal warming is taking place?
  23. 23. Portage Glacier Alaska 1914 2004Photos: NOAA Photo Collection and Gary Braasch –
  24. 24. Colorado RiverArizona June 2002 Dec 2003
  25. 25. Ocean Life Living Habitat Plants Impact of rise in CO2Emission temperature Weather of 1.8oC to 4oC Crops Sea level Human Health
  26. 26. Effects of Global Warming Rising Sea Level Increased Temperature Habitat Damage and Species Affected Changes in Water Supply
  27. 27. Effects Of Global WarmingHuman Plants & Human Marine Animals AgricultureSociety Beings Life
  28. 28. On human Society:• Siberia & Canada might experience increase in temperature from 10 to 12 degrees.• The rainfall have increased by 2 to 3% per decade over tropical regions due to high rate of evaporation.
  29. 29. On Plants & Animals:• Slowly disappearing & eventually die if the current trend in global warming countries.• There are rapid rise in global temperature in next 100 years• The wetland & coral reef may also undergo decline due to climatic changes
  30. 30. On Agriculture:• There may be negative effect on various type of crop in different regions of the world.• Soil moisture may decrease, water requirement of the crop will increase & will affect the crop yield.• Due to Green house effect, several plants cripple down their size, fruits & leaves.
  31. 31. On Human Health:• It may lead to changes in rainfall pattern & some areas may become breeding ground for mosquitoes & some other insects which are vector of disease like malaria, dengue fever, yellow fever, etc.• In low rainfall there will be waterborne disease.• Heat waves are harmful to health.
  32. 32. On Ocean Life:• It is estimated that there will be rise in sea level by 20 to30 cm by 2030.• Due to increase in the temperature, the water expands & require more space.• It also occur as a result of melting of glacier.• Due to global warming the ice extent & snow cover have decreased.
  33. 33. • Scientists use information from several sources to analyze global warming that occurred before people began to use thermometers.• Computers help climatologists to analyze past climate change & predict the future changes.
  34. 34. Measures on controlling the problemGovernment * Set some laws to limit the amount of pollutants produced by factories * Develop the skills of using renewable fuels, e.g. solar energy, wind energy
  35. 35. Measures on controlling the problem * Encourage the factories to replace fossil fuels by renewable fuels, which would not cause environmental pollution * Carry out energy saving scheme → reduce the pollution produced by burning fossil fuels * Planting more plants → reduce the pollutants e.g. CO2
  36. 36. What’s being done now to reduce our emissions?Wind Power Solar Power Fuel-Efficiency
  37. 37. Measures on controlling the problemCitizens* Reduce the use of plastic bags → as degradation of plastic emit CH4* Recycle the resources, e.g. plastic* Reduce the use of sprays → as CFCs would be emitted out
  38. 38. Measures on controlling the problem* Reduce the use of air-conditioner, which will emit CFCs* Use public transportation instead of private cars → reduce the pollutants emitted by cars