Climate Change

Climate Change Image

Causes

Greenhouse gases (eg. Carbon dioxide, methane, nitrous oxide and water vapor) These gases are produced by:
  • Burning of fossil fuels:
    coal, oil and gas produces carbon dioxide and nitrous oxide

  • Deforestation:
    Trees which act as carbon sinks absorb carbon dioxide and produce oxygen by photosynthesis. By cutting down and burning trees, the emission of carbon dioxide into the atmosphere increases and strengthens the greenhouse effect.

  • Increasing livestock farming:
    When animals(eg. cattle) digest food, they produce large amount of methane.
    * Methane has 28times higher effect on global warming than carbon dioxide

  • Fluorinated gases:
    Increasing greenhouse gases released into the atmosphere contribute towards the increase in mean temperature.
    • Climate Change Image

    Greenhouse Effects

  • Greenhouse gases accumulate in the atmosphere

  • Incoming short wavelength infrared & UV light penetrate atmosphere to reach surface of earth

  • Earth radiates longer wavelength infrared

  • Greenhouse gases in the atmosphere absorb some of this infrared and re-radiated it, warming the Earth’s surface

  • The mean temperature of earth’s surface increases
    • Climate Change Image

    Effects

  • Loss of existing species / extinction:
    Animals that are subject to TSD (temperature-dependent sex determination) are in danger due to sex ratio imbalance. This results in decline in reproduction and may lead to extinction. Ex: Sea turtles- the proportion of females is extremely higher than those of males due to increasing temperature.

  • Changes in distribution of plants & species:
    Falls in pH in oceans or rivers due to absorption of CO2 cause sea animals to migrate to more suitable areas.

  • Changes in numbers / species / growth of plants:
    Change in rainfall patterns or drought change the growing seasons or flowering times of plant species. For example, extreme temperatures make seeds difficult to germinate or grow well. Enzymes enhance the efficiency of utilization of proteins and starch. Too hot or cold temperatures make enzymes inactive. In particular, high temperature denatures enzymes and changes the shape of the active site which makes substrates no longer bind to it.