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Global Warming

Global Warming. DEFINITION. Global warming refers to the gradual temperature increase on earth .

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Global Warming

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  1. Global Warming

  2. DEFINITION Global warmingrefers to the gradual temperature increase on earth. As the planetisprogressivelyheating, climatepatternstend to changedrastically, with more and more violent and unpredictableweatherphenomenaaffecting the globe. Progressive areas are rapidlybeingreduced to deserts, others to icylands, making human life almostimpossible.

  3. The Earth’satmosphere STRATOSPHERE: in this part of the air surrounding the Earth thereis an ozonelayer. TROPOSPHERE: itis the densestlayerwhichcontainsoxygen,nitrogen,carbondioxide, water vapour and methane. EARTH EXOSPHERE MESOSPHERE THERMOSPHERE

  4. GLOBAL WARMING AND GREENHOUSE EFFECT Above the Earth’ssurfacethere is a layer of gases, like carbon dioxide (CO2) and methane (CH4), which have the effect of cushioning it. The radiation from the sun is both absorbed in the atmosphere and in the Earth’s surface. The infrared radiation becomes a problem when the layer of the gases gets too thick. When this happens, the radiations which come from the earth cannot escape in the atmosphere and are absorbed in it, causing excessive heat, which determines global warming. Besides this the absorption of the solar rays which makes our planet warm generates a natural phenomenon interrelated to global warming, called “Greenhouse effect”, which consists in the solar energy gases entrapment, which makes life possible on our planet.

  5. INFRARED RADIATION Infraredradiationis just asimportant to the Earth’sweather and climateassunlight is. Thisisbecause, for all the sunlightthat the Earth absorbs, an equalamount of IR must travel from the Earth back intospace. Ifthiswasnot the case, therewouldbe global warming or global cooling. Everythingemitsinfraredradiationbutweusually do notnoticeitbecauseitisoftenweak.

  6. THE GREENHOUSE EFFECT DISPLAYED

  7. THE GREENHOUSE EFFECT Whenthe sunrays travel and reach the atmosphere, which is made of several gases, the planet’s surface (land, water and biosphere), absorbs the solar energy. Gases like water vapour, carbon dioxide, nitrous oxide, methane and ozone trap the energy from the sun and prevent the heat from escaping back into the space. Though only a limited part of the energy passes back into space, but most of it remains in the atmosphere, the Earth heats up. These gases are known as greenhouse gases and the natural process of keeping the Earth’s temperature warm and constant is known as “greenhouse effect”.

  8. GLOBAL WARMING: CAUSES NATURAL CAUSES HUMAN CAUSES Increase in greenhousegases Burningfossilfuels (coal,oil, naturalgases) Landuse: urbanization and deforestation Pollution (due to the use of aereosols,spraycans,fridgesthat produce chluorofluorocarbons) Breeding of vastnumbers of methane-producinglivestock, suchascows. • Changes in solarradiation • Volcanicdust • Natural greenhousegases (GHG)

  9. IMPACT OF THE GREENHOUSE EFFECT Weknowthatthe planet warmed up on an average of 1°C in the past century… A RISE OF JUST 2°C WOULD INEVITABLY MEAN: • Severe storms and floods in some countries and droughts in many others; • Increased rate of acidity in seas, with definite extinction of coral and krill, food chain destruction; • No Articice in summer ; • Icemelting and submersion of more and more lands. As the Earth warms, the impact can fuel and accelerate theseevents.

  10. BEYOND 2°C Scientistspredictpossiblerises up to 6° thiscentury: ifwe do notdrastically cut greenhouse gas emissions, itwill be a disaster for allhumans and the planet, too. Ifthishappens: • Rainforestwilldie; • The ancienticesheetswillmelt; • Sea levelswilldramatically rise.

  11. A GLOBAL CLIMATE DEAL Weurgentlyneed to set strict and bindingemissions targets on the developed industrial nations. Weneed to cut GHG emissions at least 40% by 2020, and at least 80% by 2050.

  12. CARBON DIOXIDE Carbon dioxideis a natural gas, essential for life on Earth. Itisabsorbed by plantsasthey grow and emitted by vegetable and animal life forms (or producedwhenfossilfuels are burntsuchas carbon, oil). Itis the most common ‘greenhouse gas’.

  13. METHANE Methaneis the major component of natural gas and itisfound underground. Methaneis a powerfultrapping agent, and contributes to global warming by holding infraredradiationnear the Earth’ssurface. Itschemical formula is CH4, being made of oneatom of carbon and four of hydrogen. HYDROGEN CARBON

  14. Methanesources The mainmethaneemissionsources in the atmosphere are: • householdwastedecay in dumps, • naturalsources (bogs): 23%, • extraction from fossilfuels: 20%, • livestockdigestionprocess: 17%, • bacteriafound in ricefields: 12%, • heating or anaerobicdigestion of biomasses. The 60-80% of world emissionscomes out from human activities: coalmines, dumps, oilactivities, pipelines and agriculture. Besidesthis, large quantities of methane in the form of methaneclatrates are estimated to be found in oceandepths.

  15. SULFUR HEXAFLUORIDE Sulfurhexafluorideisone of the mostpowerfulgreenhousegases. Itis due to the industrial processes of the electronic industry. Sulfurhexafluorideisvery strong and the industryhastakenvarioussteps to limitits release.

  16. WATER VAPOUR Water vapourexistsnaturally in the atmosphere, because water evaporates from the oceans, formsclouds, and clouds cause precipitations. Whenvapourconcentrates in the atmosphere, ittrapsinfraredradiation, and becomes a dangerousgreenhouse gas.

  17. CHLOROFLUOROCARBONS Aerosols, hairspraycans, fridges, plastics, etc. produce a group of highlydangerousgreenhousegasescalledchlorofluorocarbonsthat cause a hole in the ozonelayer.

  18. THE OZONE LAYER Ozoneis a form of oxigenthatis made of threeatomsinstead of two. Most of the ozone in the atmosphere is in a layerconcentratedaroundtwomilesabove the Earth’ssurface. The ozonelayerabsorbsultra-violetradiationwhichisverydangerousforus and ourplanet.

  19. THE HOLE IN THE OZONE LAYER The hole in the ozonelayeriscaused by greenhousegaseslike CFC. People often confuse global warming with the hole in the ozonelayerbutthesetwophenomenathoughcorrelated are slightlydifferent.

  20. HUMAN ACTIVITY Human beings are contributing to increasegreenhousegaseslevelsthrough the burning of fossilfuels, the cutting and burning of forests, through smog emissions and chemicalprocesses.

  21. Liceo Scientifico Statale«G. Galilei»PescaraA. S. 2012-2013UDA: Global Warmingmade by: MARCO DI NARDO AND LUCA CICCONETTI Classe 2^A English Teacher: Prof.ssa Miscia Roberta

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