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Thomas and Nicolas: the greenhouse effect


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A slideshow about the greenhouse effect

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Thomas and Nicolas: the greenhouse effect

  1. 1. Saladin, Vaudout 3°4 The Greenhouse effect 1. How the Greenhouse effect works ? The phenomenon do like the glass of a greenhouse, meaning the greenhouse gases trap the heat produced by the sun. The sun produce energy. The most of this energy cross directly the atmosphere to warm up the surface of the Earth. The Earth absorbs approximately half of this energy and reflected the rest of it as infrared back to space. Then this energy is largely absorbed by greenhouse gases (naturally present in the atmosphere. The greenhouse gases allow to keep some of the heat and prevent that all of the heat back to space. Without greenhouse effect the Earth would be too cold (the temperature of the Earth would be -18°C instead of 15°C). But if the concentration of greenhouse gases would be too high, the Earth is warming because heat can not return to space. Page of1 8 ! effects-of-air-pollutants-35792450 text.php?unit=2&secNum=4
  2. 2. Saladin, Vaudout 3°4 2. The major greenhouse gases : • Water vapors (H2O) from breathing, pespiration and evaporation remain only a few days in the atmosphere. • Carbon dioxide (CO2) comes from animals breathing, plants and also combustion of fossil fuels (coal,oil,gaz). The CO2 remains 100 years in the atmosphere. • The methane (CH4) comes from swamps, rice fields, animals digestion, decomposition of litter. It is 21 times more effective than the CO2 to capt heat. This gas remains in the atmosphere for approximately 14 years. • The CFC's comes from the aerosol cans. The CFC's destroy the ozone layer and contribute si- gnificantly to the greenhouse effect. They remains in the atmosphere for approximately 1000 years. They are 10 000 times more effective than the CO2 to capt heat. In the 1970's the governments decided to stop the production of CFC's but the new gases that replace them not destroy the ozone layer but also contribute more to the greenhouse effect. • The nitrogen dioxide (N2O) is largely the result of agriculture used nitrogen fertilizers. It re- mains in the atmosphere for approximately 120 years and it is 310 times more effective than the CO2 to capt the heat. • The HFC comes from air conditioning. They pollute 1300 times faster than the CO2. Page of2 8 treach/lesson_plans tors/greenhouse-gas-emission-trends/greenhouse- gas-emission-trends-assessment-5
  3. 3. Saladin, Vaudout 3°4 3. Where these greenhouse gases come from ? A part of these gases is naturelly present into the atmosphere (H2O, CO2, ozone, CH4, N2O). It is because of this that we have life in the Earth. But the human produce most of these gases : factory chimneys, exhausts pipe, air conditioning. The deforestation, the combustion of oil and coal, factory farming... contribute to global warming. It is estimated that more than 3 billion tons of CO2 annual emissions into the atmosphere. Greenhouse gases emissions are unevenly distributed across the world as shown in the graph and carbon footprint below. Page of3 8 and-climate/greenhouse-gas-emissions greenhouse-gas.html
  4. 4. Saladin, Vaudout 3°4 4. Fortunately, nature is there ! Alone oceans store 400 gigatons of carbon per year and they reject them very slowly. Of their side, the plants absorb roughly half of the CO2 produced by the factories and other human constructions through photosynthesis (plants absorb a part of carbon dioxide through sunlight and produce dioxygen). Nature manages to limit the damage, but men producing increasingly greenhouse gases, it risks being overwhelmed. Page of4 8 siers/La-filiere-bois/La-magie-d-un-materiau-naturel
  5. 5. Saladin, Vaudout 3°4 5. What consequences for the future ? On the temperature : • The temperature has already risen by 0,5 degrees in a century. It may seen little but it was already aware of the damage it causes. If nothing is done, the temperature will continue to rise (it is estimated that it will increase 5 de- grees within a century). On the environment : • Because of the temperature rise, nature is turned upside. Where it rains much precipitation will be even stronger and vice versa for areas with low rainfall. • It is estimated that the sea level will rise one meter which will cause flooding of the coastline from all continents, where lives the vast majority (approximately 74%) of the human being ! • Many islands will disappear. • Ice melt will be more and faster which will result in the loss of species living in these environment (seals, bears, sea lions...). • This will cause storms and other weather disasters (cyclone,tsunami...). Page of5 8 greenhouse-gas_29.html 2015/10/06/la-terre-bientot-devas- tee-par-un-tsunami-geant/
  6. 6. Saladin, Vaudout 3°4 • The North Pole is warming 2 to 3 times faster than the rest of the world (in 100 years there will probably be no ice in summer). • Global oceans temperatures changes. • Ocean currents will change. On the population : • Coastal residents will move inland to avoid being submerged by the waters. • Residents of cities submerged by the oceans will lose all their property and some will die. • Due to droughts and floods, residents in the affected areas suffer from famine. • The Inuits hunting season will decrease and some of their animals food disappear. On the economy : • In areas near the Arctic, soil thawing, will move and force them to redo all the roads and almost all buildings. This will be expensive. • Even after floods, all buildings will be again. • The decline in sea ice will allow boats to pass North America and Asia. They save time in trans- porting goods and oil. • With the warming of the Arctic, it will be easier to dig oil wells. 6. How to prevent the climate changes ? To prevent the climate change the richest countries must : • Reduce them oil consumption. • Invent cleaner cars and develop the public transport. • Use more renewable energy (wind, sun and water are naturals resources to produce energy wi- thout produce greenhouse gases. We use not really these energies because the installations are very expensive). • Help the countries under development to have clean energies. • Avoid the air conditioning. • Limit the deforestation. All these measurements are expensive but we must act fast because in 20 or 30 years it will be too late ! Page of6 8
  7. 7. Saladin, Vaudout 3°4 Each persons must do a gesture : • Move on foot or on bike for the short distances. • Prefer the public transport to the car because, for example, a path Paris-Marseille on car equiva- lent to 178kg of CO2 rejected on the atmosphere against 97kg per person in plane or 3kg per person on train. • Promote the carpooling. • Don't abuse of air conditioning. • Take shower instead of bath. • Prefer product which which aren't cluttered with useless packaging. • Privileged the renewable energies. • Switch off the electrical appliances rather leave them on eve. • Don't use disposable (like tissue). • Don't overheat his home. • Isolate his home. 7. Some frightening statistics : • An inhabitant of a developed country rejects 5 tons of CO2 per year. • An inhabitant of a country under development rejects 400kg of CO2 per year. • The temperature have already increases 0.5°C in one century. • In 150 years, the amount of CO2 have increases 50% in the atmosphere. • We estimate at over 3 billions of tons of CO2 the annual release I the atmosphere. • The U.S. pours per years 10 times more of greenhouse gases than Africa but refuses to sign the protocol to Kyoto. 8. Forecasts 74% of the human population, or more than 4 billion people, could be swallowed by the oceans if we do not react quickly enough ! If nothing is done, the temperature increase of 5 degrees within a century. In 100 years, there will be no ice at the North Pole. A rise of one meter in sea level could flood half a million kilometers of coastline worldwide. Page of7 8 living/breakthrough-tool-california-measure- greenhouse-gas-emissions-25-apr-11/
  8. 8. Saladin, Vaudout 3°4 In conclusion Look the audiomemos document. Page of8 8 Logo_COP_21_Paris_2015.png Reference of the text :