SC21 Earth and Atmospheric Science Flashcards
Phase 1 of the atmosphere
- Earth’s surface was originally molten
- Surface eventually cooled and a thing crust formed
- Volcanoes keep erupting
- Atmosphere was mostly CO2 and water vapour
- Water vapour later condenses to form oceans
Phase 2 of the atmosphere
- Early CO2 dissolves into oceans
- Nitrogen gas was then formed by ammonia reacting with O2 or was released by denitrifying bacteria
- Green plants evolved, removing CO2 and producing O2
- CO2 eventually reduces and gets locked up in fossil fuels and sedimentary rocks
Phase 3 of the atmosphere
- Build up of O2 killed off organisms who couldn’t handle it
- More complex organisms evolve
- O2 created ozone layer (O3) which blocked harmful rays from Sun
- Virtually no CO2 left now
State the chemical test for oxygen
O2 gas will relight a glowing splint
How did photosynthetic organisms change the atmosphere?
They removed CO2 and produced O2 which allowed more complex organisms to evolve
How did the formation of oceans change the atmosphere?
It helped dissolve a lot of CO2 into the sea, reducing the amount in the atmosphere
Name 3 greenhouse gases
Carbon dioxide, methane, water vapour
Describe the greenhouse gas effect
1) Earth radiates some heat radiation it absorbs as IR
2) Some IR radiation is absorbed by greenhouse gases
3) Some of the IR radiation is re-emitted back towards Earth by greenhouse gases
4) Some IR is re-emitted back into space
5) The absorption and re-emission of IR radiation by greenhouse gases is what keeps the Earth warm
What is the correlation between atmospheric CO2 and fossil fuels?
As more fossil fuels are burnt, the amount of CO2 in the atmosphere increases as combustion produces carbon dioxide
How have humans impacted the concentration of greenhouse gases?
- Deforestation means less plant can reduce CO2 in atmosphere
- More people ate eating meat (livestock produce methane)
- Industrialisation means more fossil fuels are burnt
How have humans increased level of methane?
Methane is produced in the digestive processes of certain livestock. So the more animals we farm to eat, the more methane is released
How have humans increased level of CO2?
CO2 is released when we ourselves breathe, but also through combustion and the burning of fossil fuels
What are the projected effects of climate change?
The Earth’s temperature will increase, causing ice caps to melt, increasing sea levels and causing severe flooding
Harmful effects of climate change
Increasing temperature of the Earth
How can we limit climate change?
Cut down on the amount of fossil fuels we burn
