CC17 - earth and atmospheric science Flashcards
1
Q
phase 1
A
- earths surface molten for millionsofyears
- almost no atmosphere
- eruptions of volcanos released mainly CO2 + steam, methane, ammonia
2
Q
gases in earths early atmostphere
A
- very little oxygen
- mainly carbon dioxide + water vapour
3
Q
phase 2
A
- water vapour condenses to form oceans
- lots of CO2 dissolved into oceans
- nitrogen formed: ammonia+O2 or release by dentrifying bateria
- plants evolved: photosynthesis removed CO2 and produced O2
4
Q
phase 3
A
- build up of O2 killed organisms that couldnt tolerate it
- allowed evolution of more complex organisms that used O2
- oxygen created the ozone layer blocking harmful sun rays
- very little CO2 left now
5
Q
human effect on CO2 levels
A
- breathing giving out CO2
- cars, electical gadgets release CO2
- industrialized cities
- burning fossil fuels
- chopping down trees
6
Q
gases in atmosphere today
A
nitrogen - 78%
oxygen - 21%
carbon dioxide - 0.04%
7
Q
why is green house effect important
A
keeps earth warm enough for humans to live on
8
Q
green house effect
A
- energy transferred from sun
- energy from sun reaches earths surface
- most energy is absorbed increasing temp
- some energy is reflected back to space
- warm earth emits energy
- some emitted energy transferred to space
- some emitted energy absorbed by green house gases
- gases re-emit energy
- energy is transferred back to earth
9
Q
greenhouse gases causing climate change
A
- increased CO2
- conc. of methane risen (cows)
- extra greenhouse gases caused average temp to increase (global warming)
10
Q
effects of global warming
A
- severe flooding
- ice caps melting
11
Q
why is historical data much less acurate than current records
A
- data taken over fewer locations
- less accurate methods
- no records of co2 and temp level at all if you go back far enough
12
Q
how can past co2 levels be estimated
A
- analyse tree rings, fossils, gas bubbles in ice
13
Q
preventing/ slowing climate change
A
- reduce amount of greehouse gases released into atmosphere
- reduce co2 emissions: walking instead of drving
14
Q
test for oxygen
A
- checking if the gas will re-light a glowing splint, if it does, it is O2
