C9

Question 1

what is the evolution of the atmosphere?

Answer 1

phase 1- volcanoes gave out gases
phase 2- oceans, algae and green plants absorbed carbon dioxide
phase 3- green plants and algae produced oxygen

Question 2

whats the purpose of greenhouse gases?

Answer 2

Greenhouse gases like carbon dioxide, methane and water vapour act like an insulating layer in the Earth’s atmosphere
— this, amongst other factors, allows the Earth to be warm enough to support life.

Question 3

what are forms or human activity that affect the amount of greenhouse gases?

Answer 3

Deforestation: fewer trees means less CO, is removed from the atmosphere via photosynthesis.
• Burning fossil fuels: carbon that was ‘locked up’ in these fuels is released as CO2•
• Apriculture: more farm animals produce more methane through their digestive processes.
Creating waste: more landfill sites and more waste from agriculture means more CO, and methane released by decomposition of waste.

Question 4

how is increasing carbon dioxide linked to climate change?

Answer 4

The Earth’s temperature varies naturally, but recently the average temperature of the Earth’s surface has been increasing. Most scientists agree that the extra carbon dioxide from human activity is causing this increase and that this will lead to climate change.

Question 5

what are ways of reducing carbon footprints?

Answer 5

Renewable energy sources or nuclear energy could be used instead of fossil fuels.
Using more efficient processes could conserve energy and cut waste. Lots of waste decomposes to release methane, so this will reduce methane emissions.
Governments could tax companies or individuals based on the amount of greenhouse gases they emit - e.g. taxing cars based on the amount of carbon dioxide they emit over a set distance could mean that people choose to buy ones that are more fuel-efficient and so less polluting.
Governments can also put a cap on emissions of all greenhouse gases that companies make — then sell licences for emissions up to that cap.
There’s also technology that captures the CO, produced by burning fossil fuels before it’s released into the atmosphere — it can then be stored deep underground in cracks in the rock such as old oil wells.