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How much of the atmosphere is composed of nitrogen and oxygen?
78% nitrogen 21% oxygen
What are the other gases in the atmosphere?
CO2
Argon
Water vapour
Methane, ozone
What are layers of atmosphere divided into based on?
Temperature changes
What are the atmospheric layers where most interactions related to living systems occur?
At troposphere and stratosphere
What is the lowest layer of the atmosphere?
Troposphere- 10km
Describe the troposphere
Where weather phenomena occurs e.g. cloud formation, precipitation, mixing of gases
What’s the second lowest layer?
Stratosphere (10 to 50km)
Describe the stratosphere
Contains ozone layer
High concentration of ozone that absorb and block most of the sun’s harmful UV
Why is the ozone layer crucial?
Protecting life on earth from excessive UV radiation
What are the reactions in the troposphere?
Chemical reactions involving pollutants, greenhouse gases and atmospheric particles can impact air quality and climate
What are the reactions in the stratosphere?
Chemical reactions involving ozone play vital role in maintaining ozone layer and protecting earth from harmful UV radiation
What are the storages in the atmosphere?
Storage for gases (greenhouse gases)
What are the flows in an atmospheric system?
Flows of gases and particles
Driven by air currents, weather patterns and atmospheric circulation
Contribute to movement and redistribution of gases
What are the inputs of the atmospheric system?
Natural inputs: gases from volcanic eruptions, gas emissions from plants and others living organisms, dust particles from desert regions
Anthropogenic inputs from human activities (release of greenhouse gases, air pollutants from industrial processes, aerosols from combustion)
What are the outputs of the atmospheric system?
Releases gases by respiration / photosynthesis
Pollutants and aerosols can be removed through precipitation, dry deposition and chemical reactions
What are the exchanges with other earth systems?
Biosphere (plants, animals, microorganisms)
Hydrosphere (oceans, lakes, rivers)
Lithosphere (landmasses, rocks)
Why is exchanging gases important?
Shaping climate patterns and weather events
Why has the composition of the atmosphere changed over time?
Atmosphere had high levels of CO2, lacked oxygen in early stages
Millions of years, photosynthetic organism evolved, released oxygen
Volcanic activity, meteorite impacts have influenced atmospheric composition
Where do clouds form?
Troposphere
What is this layer characterised by?
Decreasing temperature
Increasing altitude
Cooling + condensation of water vapour
What contributes to the albedo effect?
Clouds
Define albedo
Reflectivity of a surface, indicating how much solar radiation reflected back into space
What does this reflection of solar radiation help with?
Cool the Earth’s surface
How can clouds act as a feedback mechanism?
Low clouds: net cooling effect by reflecting more sunlight
High clouds: net warming effect by trapping more outgoing IR
What can affect cloud formation?
Aerosol pollution
Changes in atmospheric circulation patterns
Climate change
What are the gases affected by human activity?
Ozone
Carbon dioxide
Water vapour
Methane
Nitrous oxide
Aerosols
What human activity affects ozone?
Release of ozone-depleting substances e.g. CFCs (aerosols, refrigerants, pesticides) reduces ozone
What is the effect of depleting ozone?
Increases UV radiation reaching earth’s surface, harming organisms (phytoplankton, plants, humans)
What human activity affects carbon dioxide?
Burning fossil fuels, deforestation and industrial processes increase carbon dioxide
What is the effect of CO2?
Enhances greenhouse effect, leading to global warming and climate change, affecting ecosystems and biodiversity
What human activity affects water vapour?
Land use changes, agriculture, industrial processes
What is the effect of water vapour?
Alters precipitation patterns
Contribute to droughts, excessive rainfall
Impact ecosystems, agriculture, water availability
What human activity affects methane?
Agriculture
Fossil fuel extraction
Waste management
What is the effect of methane?
Enhances greenhouse effect, leading to global warming and climate change
- Melts permafrost, ice caps
- Contributes to sea-level rise
What is the human activity affecting nitrous oxide?
Agriculture
Combustion processes
Industrial activities
What is the effect of nitrous oxide?
Contributes to global warming and climate change, affects air quality
What is the human activity on aerosols?
Produced by industrial processes, biomass, burning and vehicle emissions
What is the effect of aerosols?
Alters radiative properties of atmosphere
Affects air quality
Influence cloud formation
Impact ecosystems and human health
What form of energy does sun emit?
Solar radiation, including visible light and UV
What happens to solar radiation when it reaches the Earth’s atmosphere?
Some thermal energy is reflected from the earth’s surface
Most thermal energy is absorbed and re-emitted by the earth’s surface
What happens to the thermal energy after being re-emitted from the surface?
Some thermal energy passes straight through the atmosphere and is emitted into space
Some thermal energy is absorbed by greenhouse gases and re-emitted in all directions
What are the main greenhouse gases?
Carbon dioxide, methane, water vapour
How do greenhouse gases affect Earth’s thermal energy?
They act like a blanket, allowing sunlight to pass through but prevent significant amount of IR from escaping back into space
What is the result of greenhouse gases trapping IR?
Reduces thermal energy lost to space and keeps the earth warm
What is the greenhouse effect?
The process where greenhouse gases trap heat within the Earth’s atmosphere keeping the planet warm
Why is the greenhouse effect important?
Ensures Earth is warm enough for life
Without it, the Earth would experience dramatic temperature fluctuations
Planet would be uninhabitable without insulating effect of greenhouse gases
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