3.a. Human factors can disturb and enhance the natural processes and stores in the water and carbon cycles

Question 1

What impact does fossil fuel consumption have on flows and stores of carbon

Answer 1

• high global dependency on fossil fuels- drive global industralisation and urbanisation
• approximately 10 billion tonnes of CO2 are released into atmosphere annually
• anthropogenic carbon emissions account for less than 10% of the natural influx, impact carbon stores of the atmosphere, oceans and biosphere
• combustion of ff+resulting transfer of carbon from geological stores to atmosphere and oceans is main cause of global warming. Without absorption of anthropogenic carbon by oceans, todays atmospheric CO2 concentrations would exceed 500ppm

Question 2

How does carbon sequestration impact on flows and stores of carbon

Answer 2

• one possible solution is carbon capture and storage- removal of CO2 from emissions by power stations, then compressed+transported to storage areas and then injected into porous rocks deep underground
• in USA, 40% of all CO2 emissions are from oil and gas fired power stations. CCS could reduce these emissions by 80-90%
• this is limited by high capital costs e.g. cost more than 1 billion and by the fact that the process uses large amounts of energy and requires storage reservoirs with specifical geological conditions to prevent leakage