The Earth's Atmosphere - C9

  • Created by: mevan
  • Created on: 27-04-21 20:43

proportions of different gases in the atmosphere

early atmosphere:

(these are just estimates because it was so long ago, no one was around to measure the real values)

  • nitrogen = trace
  • oxygen = little/none
  • carbon dioxide = the vast majority
  • water vapour = lots
  • other gases = trace


(for 200 million years, the proportions have been roughly the same)

  • nitrogen = 80%
  • oxygen = 20%
  • carbon dioxide = <1%
  • water vapour = trace%
  • other gases = trace%
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atmospheric activity during the first billion year

volcanic activity

  • released gases: ammonia (NH3), methane (CH4), water vapour (H2O), and carbon dioxide (CO2).
  • it was hot, dry and humid. there was no liquid water.

reduction in carbon dioxide

  • dissolved in the ocean.
  • formed limestone, sedimentary rocks, and fossil fuels.
  • absorbed by photosynthetic organisms.

liquid H2O formed

  • as the earth cooled, the water vapour condensed, which formed the oceans.

oxygen increase

  • once oceans formed, life was able to evolve.
  • algae and eventually plants photosynthesised to produce oxygen.
  • photosynthesis balanced equation: 6CO2 + 6H2O --> C6H12O6 + 6O2
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greenhouse gases and reasons for their increase (p

greenhouse gases are carbon dioxide, water vapour and methane. human activity can increase the amount of these gases in the atmosphere:

combustion of fossil fuels

  • produces carbon dioxide.
  • it has increased because there are more people, so there is a greater demand for electricity. there is also more technology requiring fuel/electricity.


  • produces carbon dioxide
  • it has increased because of the increased population, we need more resources like wood and paper and also more room for agriculture and housing.
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greenhouse gases and reasons for their increase (p

cattle and rice production

  • produces methane.
  • it has increased because there are more people, and a greater demand for food.

more waste on landfill sites

  • produces methane
  • it has increased because there are more people, there is more waste which leads to methane being produced.
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peer reviews and modelling complex systems

peer reviews

a peer review is work/data that is checked by other scientists to ensure that all the conclusions/findings are correct and valid. it is important that an impartial company carries this out because it avoids biases within reviews.

based on peer-reviewed evidence, many scientists believe that human activities will cause the temperature of the earth's atmosphere to rise and that this will result in global climate change.

modelling complex models

it is extremely difficult to model complex systems like climate change. it can result in simplified models when presenting to the public, which leads to:

  • speculation
  • biased opinions based on one part of the evidence
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the greenhouse effect

1) short wavelength radiation is emitted by the sun. it passes through the earth's atmosphere

2) the short wavelength radiation is absorbed by the earth's surface.

3) longer wavelength radiation is emitted by the earth's surface

4) some of this passes through the atmosphere and escapes into space

5) however, some is absorbed by greenhouse gases in the earth's atmosphere.

6) the issue with this is that as the concentration of greenhouse gases increases, more radiation is absorbed, causing the earth to hear up and global warming to occur.

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potential effects of global climate change

water stress -

  • reduction in fresh water supplies as the ice caps melt.

distribution of wildlife species -

  • insects can migrate further
  • the migration patterns of birds are disrupted.

temperature stress

  • too hot in certain places for some species of plants/ animals to survive

changes in the producing capacity

  • droughts cause the production of foods to decrease, leading to famines
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carbon footprint

carbon footprint is the total amount of carbon dioxide and other gases a product, service, or event emits over its full life cycle.

reducing your carbon footprint

  • using alternative energy resources like solar, wind, tidal and geothermal power are renewable, and give off no carbon dioxide emissions.
  • conserving energy and using it efficiently in homes, using items like LED light bulbs, double glazing and insulation.
  • energy efficient cars like electric cars which give off no emissions, or cars with better economy, which means that they use less fuels.
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government initiatives

carbon capture

  • take carbon dioxide from the atmosphere
  • store/deposit in underground non-porous rocks
  • the carbon dioxide is now locked away in the rock

carbon off-setting

  • increasing the carbon "sink"
  • by planting more trees - reforestation

carbon neutrality

  • plant as many trees as are needed to offset or equal the amount of carbon dioxide released
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atmospheric pollutants from fuels (part 1)

carbon dioxide:

  • produced in complete combustion
  • reduced by using alternative fuels
  • effects the environment by contributing towards global warming

carbon monoxide

  • produced in incomplete combustion
  • reduced by converting it to carbon dioxide using a catalytic converter
  • it is toxic

solid carbon particulates

  • produced in incomplete combustion of solid fuels
  • reduced by filtering systems and increasing airflow
  • it contributes to global dimming and smog
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atmospheric pollutants from fuels (part 2)

sulfur dioxide

  • produced when there are impurities within the fuels (sulfur) (mostly in coal)
  • reduced by capturing/ filtering it using limestone
  • impacts the environment because it causes acid rain

oxides of nitrogen (NOx)

  • produced in very high temperature combustion
  • reduced by converting it into nitrogen (N2) using catalytic converters
  • causes acid rain
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the carbon cycle

  • carbon released into the atmosphere through:
    • combustion from power plants
    • respiration in algae, plants, and animals
    • microbial respiration in dead animals
    • volcanic erruptions
  • carbon taken out of the atmosphere through:
    • plant and algae photosynthesis
  • plants die and decay, as do animals who have eaten the plants
  • the dead bodies go through sedimentation
  • this turns them into sedimentary rock and fossil fuels
  • which is used by the power plants
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