Atmosphere of the Earth Flashcards
What was the early atmosphere mostly composed of?
Carbon dioxide
How did oceans form?
Water vapour condensing as the Earth cooled.
How did the amount do CO2 in the atmosphere decrease to todays levels? Give 3 reasons.
Dissolved in oceans, used in photosynthesis, converted to fossil fuels, precipitated as insoluble metal carbonates
When did life on Earth start to appear?
~2.7 billion years ago
Why did the appearance of early life forms decrease the levels of CO2 in the atmosphere?
It was used as a reactant in photosynthesis; atmospheric oxygen increased as release as product
How has the amount of nitrogen in the atmosphere changed over time and why?
Increases slowly - very stable molecule
What is the current composition of the atmosphere?
- ~80% nitrogen
- 20% oxygen
- Trace amounts of other gases like CO2, water vapour and noble gases
What is a greenhouse gas?
A gas that traps radiation feom the Sun.
What type of radiation do greenhouse gases absorb?
Longer wavelength infrared radiation.
Name 3 greenhouse gases.
Methane, carbon dioxide, water vapour
Give 2 days human activity increases atmospheric carbon dioxide levels.
Combustion of fossil fuels, deforestation
Give 2 days human activity increases atmospheric methane levels.
Rice farming, cattle farming
What is global climate change?
An change in long-term weather patterns across the planet
What are some possible effects of climate change?
Sea levels rising, extreme weather events, changes to precipitation patterns/amounts, changes to ecosystems and habitats, melting of glaciers
What is a carbon footprint?
The amount of carbon a product, process or person releases into the atmosphere over its lifetime
How is carbon monoxide formed?
Incomplete combustion
What is the hazard associated with carbon monoxide?
Colourless and odourless toxic gas
How is sulfur dioxide formed?
Sulfur impurities in fossil fuels reacting with oxygen during combustion
What are the hazards associated with sulfur dioxide and nitrogen oxides?
Acid rain, respiratory problems
How are oxides of nitrogen formed?
Atmospheric oxygen and nitrogen reacting in heat of combustion engine
