Global Warming

• Processes keeping O2 and CO2 levels balanced:

  • Respiration - takes in O2, releases CO2.
  • Combustion - takes in O2, releases CO2.
  • Photosynthesis - takes in CO2, releases O2.
• Combustion can occur naturally (forest fires due to lighting strikes, volcanic eruption) but increase in combustion of fossil fuels by humans is releasing large amounts of previously locked up CO2 - enhancing global warming.
• Deforestation has reduced number of trees on Earth do less plants to carry out photosynthesis, so less CO2 being remove.
• Increased number if animals and humans means more Co2 and not enough oxygen.
• • The excess CO2 strongly absorbs heat from the sun, causing the Earth’s average temperature to rise.
• Green house effect:

  • UV radiation from sun goes to Earth‘s surface, but done is reflected back into space by the ozone layer.
  • Some infrared radiation goes out into space, but some is trapped in air atmosphere by greenhouse gases (CO2, water vapour, methane).
• • Carbon emissions can be controlled using ‘carbon capture’ - CO2 is contained and stored in secure locations like disused mines.
• Global warming could cause…

  • hotter summer on some parts of work, leading to draughty and expansion of desert regions.
  • increased rainfall in some places, leading to floods.
  • extreme weather.
  • melting ice caps.
  • rising sea levels.