Atmosphere

• The greenhouse effect is the warming of Earth's surface caused by gases that trap heat from the sun.
• Carbon dioxide (CO2) is one of the most important greenhouse gases
• Carbon dioxide, methane, nitrous oxide, fluorinated gases are all greenhouse gases
• Increased levels of greenhouse gases lead to more energy being trapped on Earth which leads to global warming
• This causes an increase in temperature at ground level
• Greenhouse gases absorb long-wave radiation emitted by the earth’s surface and reemit it back to the atmosphere as thermal energy
• First atmosphere

  Formed from a molten lump of iron, rock and dissolved molecules
• Formation of the first atmosphere

  1. Denser material sank making the iron core

  2. Rocky material formed the mantle

  3. Lightest rocks formed the crust

  4. Dissolved gases escaped from the molten rock in volcanic activity
• Main gases in the first atmosphere

  • Carbon dioxide
  • Carbon monoxide
  • Sulfur dioxide
  • Ammonia
  • Hydrogen cyanide
  • Nitrogen
  • Nitrogen oxides
  • Hydrogen sulfide
• Water is present in large quantities as water vapour/steam
• There is NO molecular oxygen as it is too reactive to exist alone
• Early changes to first atmosphere

  1. Cooling

  2. Water vapour condensing and turning into clouds

  3. Nonstop rain for about a million years
• Oceans

  Formed from the water that condensed, and were topped up by icy comets crashing into Earth
• Seawater becoming salty

  Water dissolved soluble material in rocks
• Carbon dioxide in atmosphere

  1. Dissolving into water

  2. Reacting to form carbonate rocks
• Simple life has developed

  Within a billion years
• Simple life forms

  • Bacterial
  • Simple single celled plants
  • Simple single celled animals
• Development of current atmosphere

  1. Carbon dioxide and water

  2. Glucose and oxygen
• Carbon dioxide almost disappears from atmosphere
• Oxygen built up and is maintained by photosynthesis
• Nitrogen remained from the early atmosphere due to its lack of reactivity
• Argon remained for the same reason
• What is the atmosphere made from?

  • Evolution of Atmosphere
  • Effect of human activity
• Formation of the first atmosphere

  1. Molten lump was a mixture of iron, rock and dissolved molecules

  2. Denser material sank making the iron core

  3. Rocky material formed the mantle

  4. Lightest rocks formed the crust

  5. Dissolved gases escaped from the molten rock in all the volcanic activity
• Main gases in the first atmosphere


  • Carbon dioxide
  • Carbon monoxide
  • Sulfur dioxide
  • Ammonia
  • Hydrogen cyanide
  • Nitrogen
  • Nitrogen oxides
  • Hydrogen sulfide
• Water is present in large quantities as water vapour/steam. There is NO molecular oxygen as it is too reactive to exist alone.
• Early changes to first atmosphere

  1. Water vapour condensed and turned into clouds

  2. It started to raining

  3. Water formed the oceans

  4. Water dissolved all the soluble material in the rocks and so the seas became salty

  5. Large amounts of the carbon dioxide in the atmosphere dissolve into the water and some of the of this reacts to form carbonate rocks
• Within a billion years simple life has developed. Bacterial and simple single celled plants and animals develop.
• Development of current atmosphere

  1. Once plants evolve photosynthesis begins

  2. Carbon dioxide and water ⟶ glucose and oxygen

  3. Carbon dioxide almost disappears from atmosphere

  4. Oxygen built up and is maintained by photosynthesis

  5. Nitrogen remained from the early atmosphere due to its lack of reactivity

  6. Argon remained for the same reason
• Current Atmosphere composition


  • Nitrogen (N2) - 78%
  • Oxygen (O2) - 21%
  • Argon (Ar) - 1%
  • Carbon Dioxide (CO2) - 0.04%
• Carbon dioxide released by burning fossil fuels (coal, oil and natural gas)


  Carbon Dioxide is a greenhouse gas that holds heat in the atmosphere
• Global Warming


  Result of increase in temperature of atmosphere
• Carbon dioxide in atmosphere is just one part of a cycle involving carbon that involves the atmosphere, rocks and soil and living things. Humans have disturbed the balance of this cycle.
• Greenhouse Effect


  Some gases result in heat being kept in the atmosphere more than others. Water, carbon dioxide and methane are the gases with the biggest overall effect.
• The Greenhouse Effect


  1. Radiation from sun passes through atmosphere

  2. Absorbed at surface

  3. Reradiated at longer wavelengths (infra-red=heat)

  4. Greenhouse gases absorb i.r./heat

  5. Then reradiate it in all directions keeping much of the heat in the atmosphere
• Global warming is NOT the greenhouse effect. Global warming IS an effect of a greater greenhouse effect.
• Over the last 200 years the average temperature of the planet has increased by over 1°C. Most of this has been due to humans.
• Burning of fossil fuels and clearing of forests/woodland has increased the amount of CO2. Livestock farming and the melting of permafrost has increased the amount of CH4 (methane).
• Whatever the reason global warming has an impact: Sea level changes, More extreme weather, Changes in sea currents and resulting regional climatic changes, Decrease in biodiversity – species loss, Food, water and resource issues leading to conflict or human disasters.
• What resources do humans use?

  • Natural Gas
  • Crude Oil
  • Metal ores - Iron, coper, nickel, lithium, etc.
  • Clay, rocks