C9 : Chemistry of the atmosphere Flashcards
what gases make up the earths atmopsphere
nitrogen - 80%
oxygen - 20%
other gases (carbon dioxide and water vapour ex.) - <1%
what happened in the earths first billion years
the earth was very dry and had intense volcanic activity leading to lots of carbon dioxide, water vapour and nitrogen along with smaller amounts of methane and ammonia. this meant that the atmosphere was mostly co2 like mars and venus today
what happened to early water vapour on earth
formed the oceans as it condensed
allowing co2 to dissolve in them where it forms sediments in the sea bed
what happened to earth ~2.7 billion years ago
slowly at first as algae and green plants evolved over the years they photosynthesise they decrease carbon dioxide levels and increase oxygen levels allowing for more complexed life to evolve like animals
what happened to the plants when they died
they died and became buried in the seas bed in layers of sediment
over millions of years it became compressed to form rock, oil and gas. this trapped the carbon and stopped it form getting back into the atmosphere
what forms when organisms are buried
it depends on what organism is being buried and in which conditions involved
how are crude oil and natural gases formed
formed from dead plankton (tiny micro organisms)
how is coal formed
type of sedimentary rock that is formed from dead plant material
how is limestone formed
sedimentary rock
made from calcium carbonate from shells and skeletons
atmosphere
a protective layer of gases around the surface of earth
greenhouse effect
- atmosphere acts a like a blanket or greenhouse to keep in the suns heat energy
- heat energy comes down towards the earth in the from of short wavelength radiation, some of this is absorbed and heats up the ground
- most of it is remitted or reflected towards the sun or space in the form of longer wavelength;eight radiation some makes it into space
- most of it ends up hitting particles of gas in our atmosphere which absorb the energy
- short delay and they remit this energy in random directions this can go back to space or more likely hits another gas particle
- this process of getting absorbed and remitted happened over and over again
- this means that the heat energy stays close to earth far longer to if there was no atmosphere keeping the earth at a warm temp
which gases are greenhouse gases
carbon dioxide
water vapour
methane
why is the greenhouse effect a problem
the greenhouse effect it getting stronger as we produce so much of the greenhouse gases leading to global warming
why are carbon dioxide levels rising
- burning lots of fossil fuels releases from the fuel as it was locked up inside
- chopping down lots of trees (deforestation) so not photosynthesis
why are methane levels increasing
- farm animals produce methane during digestion which gets released into the atmosphere
- we produce huge amount of waste which means methane is sometimes released as it is decomposed by microorganisms
how do we know that the earth is getting warmer
we have records going back hundreds of years and can see the steady increase
why do know not know consequences of global warming
harder to know
hard for scientist to make models of what will happen
climate change
effects of global warming on the climate on the planet
climate
long term weather patterns across the entire planet
climate change effects
rare weather events like droughts, hurricanes and floods are more common and severe
consequence of global warning
sea level rise, high temps cause ice to melt and water warms up and expands so volume increases
genral impact of climate change
as temps and rainfall patterns increase
species that were adapted to environment might not be able to survive any more so might be able to adapt or migrate other regions where the conditions are better
lost can’t in time
means that biodiversity will fall
