Topic 9 Flashcards
1
Q
Evolution of the atmosphere (PHASE 1)
A
- first billion years of Earth were covered in volcanoes
- atmosphere was CO2, nitrogen, water vapour, methane and ammonia were released from eruptions
2
Q
Evolution of the atmosphere (PHASE 2)
A
- water vapour condensed, forming oceans
- CO2 dissolved in oceans. Later forming sediment
- Green plants/algae evolved and absorbed CO2 for photosynthesis
- marine animals evolved; their skeletons contain carbonates from ocean
- carbon became locked up in rocks/fossil fuels after organisms die
3
Q
Fossil fuels
A
- Crude oil + natural gas
Formed from deposits of plankton under seabed - Coal
Sedimentary rock formed from thick plant deposits - Limestone
Sedimentary rock (calcium carbonate) from dead organism shells/skeletons
4
Q
Evolution of the atmosphere (PHASE 3)
A
- Green plants produced oxygen by photosynthesis
- Algae evolved first, then green plants
- rise in oxygen levels led to the evolution of animals
- atmosphere today = 80% nitrogen, 20% oxygen, >1% CO2, water vapour, noble gases
5
Q
GHGs & climate change
A
- CO2, methane and water vapour act as an ‘insulating layer’ in the atmosphere
- GHGs don’t absorb short w.l. radiation from sun
- GHGs absorb AND re-radiate long w.l. radiation from Earth (greenhouse effect)
- climate change affects biodiversity
6
Q
Carbon footprints
A
- the amount of CO2 released over full life-cycle of something
- measuring c. footprint is difficult due to many aspects contributing to emissions
- Government taxes/caps on emissions can reduce footprint
- however, economic development can be impacted
7
Q
Air pollution
A
- during combustion, carbon and hydrogen are oxidised
- not enough oxygen present leads to incomplete combustion
- CO binds to haemoglobin meaning less oxygen in body (respiratory problems)
- soot is black/dirty causing global dimming
- SO2 & NOx released from car exhausts forming dilute acids
- acidic rain then damages plants
