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Activity Discussion Science & Technology CLASS8 Reply To: CLASS8

  • Darsana

    June 23, 2023 at 2:39 pm
    Not Helpful

    GREENHOUSE GASES (also known as GHGs) are gases in the earth’s atmosphere that trap heat. During the day, the sun shines through the atmosphere, warming the earth’s surface. At night the earth’s surface cools, releasing heat back into the air. But some of the heat is trapped by the greenhouse gases in the atmosphere.<div>


    GREENHOUSE EFFECT is produced by greenhouse gasses (GHG) like water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxides (NxO) and ozone (O3).

    GLOBAL WARMING is a gradual increase in the earth’s temperature generally due to the greenhouse effect caused by increased levels of carbon dioxide, CFCs, and other pollutants.


    1. Man – made causes

    a) Deforestation

    Plants are the main source of oxygen. They take in carbon dioxide and release oxygen thereby maintaining environmental balance. Forests are being depleted for many domestic and commercial purposes. This has led to an environmental imbalance, thereby giving rise to global warming.

    b) Use of Vehicles

    The use of vehicles, even for a very short distance results in various gaseous emissions. Vehicles burn fossil fuels which emit a large amount of carbon dioxide and other toxins into the atmosphere resulting in a temperature increase.

    C) Chlorofluorocarbon

    With the excessive use of air conditioners and refrigerators, humans have been adding CFCs into the environment which affects the atmospheric ozone layer. The ozone layer protects the earth surface from the harmful ultraviolet rays emitted by the sun. The CFCs have led to ozone layer depletion making way for the ultraviolet rays, thereby increasing the temperature of the earth.

    d) Industrial Development

    With the advent of industrialization, the temperature of the earth has been increasing rapidly. The harmful emissions from the factories add to the increasing temperature of the earth.

    In 2013, the Intergovernmental Panel for Climate Change reported that the increase in the global temperature between 1880 and 2012 has been 0.9 degrees Celsius. The increase is 1.1 degrees Celsius when compared to the pre-industrial mean temperature.

    e) Agriculture

    Various farming activities produce carbon dioxide and methane gas. These add to the greenhouse gases in the atmosphere and increase the temperature of the earth.

    f) Overpopulation

    An increase in population means more people breathing. This leads to an increase in the level of carbon dioxide, the primary gas causing global warming, in the atmosphere.

    2. Natural Causes

    a) Volcanoes

    Volcanoes are one of the largest natural contributors to global warming. The ash and smoke emitted during volcanic eruptions goes out into the atmosphere and affects the climate.

    b) Water Vapour

    Water vapour is a kind of greenhouse gas. Due to the increase in the earth’s temperature, more water gets evaporated from the water bodies and stays in the atmosphere adding to global warming.

    C) Melting Permafrost

    Permafrost is frozen soil that has environmental gases trapped in it for several years and is present below Earth’s surface. It is present in glaciers. As the permafrost melts, it releases the gases back into the atmosphere, increasing Earth’s temperature.

    d) Forest Blazes

    Forest blazes or forest fires emit a large amount of carbon-containing smoke. These gases are released into the atmosphere and increase the earth’s temperature resulting in global warming.


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