C13: Earth's Atmosphere Flashcards
what is the atmosphere
layer of gas surrounding Earth
what was early atmosphere composed of
mostly carbon dioxide
how did oceans form
water vapour condensing as Earth cooled
how did carbon dioxide levels decrease
- dissolved in oceans
- photosynthesis
- converted to fossil fuels
- precipitated as insoluble metal carbonates
when did life start to appear and how did it affect the atmosphere
2.7 billion years ago - oxygen increased as it was released in photosynthesis
how has amount of nitrogen in atmosphere changed
increased slowly as it is a very stable molecule
why can scientists not be sure about the Earth’s atmosphere
it was billions of years ago and evidence is limited
how much nitrogen in atmosphere today
about 80%
how much oxygen in atmosphere today
about 20%ther
than nitrogen and oxygen, what gases in atmosphere today
carbon dioxide
water vapour
noble gases
what is a greenhouse gas
a gas that traps radiation from the sun
what type of radiation do greenhouse gases absorb
longer wavelength infrared radiation
three greenhouse gases
water vapour
carbon dioxide
methane
two ways human activity has increased carbon dioxide
burning fossil fuels
deforestation
two ways human activity has increased methane
rice farming
cattle farming
what is global warming
increase in overall global temperature
what is global climate change
change in long term weather patterns across the planet
what are some effects of climate change
- rising sea levels
- extreme weather events
- changes in the amount and time of rainfall
- changes to ecosystems and habitats
- polar ice caps melting
what is a carbon footprint
amount of carbon a product, process or person releases into the atmosphere over its lifetime
how is carbon monoxide formed
incomplete combustion - colourless and odourless toxic gas
how are particulates formed
incomplete combustion, leads to global dimming, respiratory problems and can casue cancer
how is sulfur dioxide formed
sulfur impurities in fossil fuels react with oxygen in combustion and it is a gas which causes acid rain and respiratory problems
how are oxides of nitrogen formed
atmospheric oxygen and nitrogen react in the heat of a combustion engine it causes acid rain and respiratory problems
