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Global Warming and Green House Effect (7th standard)

  2. The Greenhouse Effect  Greenhouse : glasshouse designed to trap the heat of the sun  Uses: for production of fruits, vegetables, and flowers in the temperate countries  Heated naturally by the incoming rays of the sun and artificially by using hot air and water.  The system of trapping heat in an enclosed area is known as the greenhouse effect
  3. Causes of Greenhouse Effect  Natural process  Necessary for the survival of living things as it keeps the earth warm  The amount of greenhouse gases have increased dramatically over the last thousand years
  4. Causes of Green House Effect  Burning of Fossil Fuels : • The use of fossil fuels have resulted in the release of Carbon dioxide into the atmosphere. This carbon dioxide heats up the earth’s surface and the oceans • Every year, human activities are causing the release of about seven billion tonnes of carbon dioxide into the atmosphere.  Deforestation: • Because of the felling old trees, or deforestation, less plants are available to take-up carbon dioxide from the atmosphere. When the fallen trees and plants slowly decompose, they release the stored carbon dioxide into the atmosphere
  5.  Population Explosion: • With the increase in population, the demand for house, transport, and fuel has increased. These demands increase the consumption of fossil fuels that adds to the greenhouse effect.  Farming: • Farming provides food for the ever growing world population • Fertilizers used in the farms contain nitrous oxide, a greenhouse gas into atmosphere • Therefore, farming is also responsible for creating greenhouse effect
  6. Global Warming and Green House Effect  Increase in the greenhouse gases through burning of fossil fuels has disturbed the ecological balance of the earth  Since the Industrial Revolution, the temperature of the earth is increasing  Gradual increase in the earth’s average temperature is referred to as global warming  Primary source of the global warming is the increase in the greenhouse gases
  7. Various human activities that are responsible for global warming are :  Burning of fossil fuels for electricity generation and transportation  Emission of smoke and harmful gases from factories  Pollution caused in the upper atmosphere due to the flying of aeroplanes  Deforestation of forests for agricultural and industrial purposes  Forest fires
  8. Impacts of global warming  Heat waves  Torrential rains and flooding  Rise In the sea level  Shrinking glaciers  Disease outbreak  Loss of biodiversity
  9.  Heat Waves: • Drought conditions and wildlife are associated with increased heat waves • The disastrous heat waves are the cause for the loss lives throughout the world  Torrential Rains and Flooding: • The intensity of precipitation events has increased the last few decades • There are frequent floods and landslides
  10.  Rise in the Sea Level : • Rising sea level is one of the undeniable impacts of the global warming • Sea levels around the world rose by an average of 10-20 cms during the twentieth century • This would further accelerate because of the melting of ice sheets on Greenland and Antarctica • Continued rising of sea will submerge the densely populated coastal regions of the world  Shrinking Glaciers: • Glaciers are a source of fresh water in the world • These glaciers are retreating because of the increase in temperature • The shrinking of these glaciers will create a shortage of fresh water • In Asia, the glaciers of the Himalaya are retreating at a record pace
  11.  Disease Outbreak: • The increased temperature accelerates the growth of disease causing organism, especially mosquitoes. • The warming of earth has been associated with the spread of tropical disease like malaria, dengue fever, and yellow fever in the higher altitude regions.  Loss of Biodiversity: • The increase in sea surface temperature has resulted in coral bleaching • The melting ice in the Arctic is endangering the survival of polar bears
  12. Mitigating Global Warming  Global Warming may be brought under control by the following measures: • Replacing coal and petroleum with the alternative source of energy • Using energy efficient appliances and reducing the carbon footprint • Use of recyclable and organic materials in the construction of buildings • Controlling deforestation of rainforests all over the world • Saving fuel consumption and the cost by use of the public transport • Initiating afforestation and reforestation to plant more trees • Practising reuse, reduce, and recycle
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