Recall that the gases produced by volcanic activity formed the Earth’s early atmosphere

Describe that the Earth’s early atmosphere was thought to contain:

a) little or no oxygen
b) a large amount of carbon dioxide
c) water vapour
d) small amounts of other gases

and interpret evidence relating to this

Explain how condensation of water vapour formed oceans

Explain how the amount of carbon dioxide in the atmosphere was decreased when carbon dioxide dissolved as the oceans formed

Explain how the growth of primitive plants used carbon dioxide and released oxygen by photosynthesis and consequently the amount of oxygen in the atmosphere gradually increased

Describe the chemical test for oxygen

Describe how various gases in the atmosphere, including carbon dioxide, methane and water vapour, absorb heat radiated from the Earth, subsequently releasing energy which keeps the Earth warm: this is known as the greenhouse effect

Evaluate the evidence for human activity causing climate change, considering:

a) the correlation between the change in atmospheric carbon dioxide concentration, the consumption of fossil fuels and temperature change
b) the uncertainties caused by the location where these measurements are taken and historical accuracy

Describe:

a) the composition of today’s atmosphere
b) the potential effects on the climate of increased levels of carbon dioxide and methane generated by human activity, including burning fossil fuels and livestock farming
c) that these effects may be mitigated: consider scale, risk and environmental implications