3. Human impacts on carbon cycle

Question 1

What % of global energy consumption is made of fossil fuels?

Answer 1

87% in 2013

37% oil, 27% natural gas etc

Question 2

How much CO2 does fossil fuel consumption release annually?

Answer 2

10 billion tonnes of CO2 into the atmosphere annually which has increased atmospheric CO2 concentration by 1ppm

Question 3

How much CO2 has remained in atmosphere since 1750?

Answer 3

879 GT of anthropogenic CO2 emissions have remained in atmosphere, increasing concentrations form 280ppm to 400ppm

Question 4

CO2 levels are currently the highest since how many years ago?

Answer 4

800,000 years ago

Question 5

What % of anthropogenic emissions make up the carbon cycle (into the atmosphere)?

Answer 5

Only 10% however this has severely disrupted carbon stores

Question 6

Where have most of the anthropogenic carbon emissions gone?

Answer 6

• 879 GT into atmosphere
• 590 GT into ocean
• 528 GT to land

Question 7

What process can combat anthropogenic carbon emissions?

Answer 7

Using carbon capture and storage (CCS) = the removal of CO2 from emissions by thermal power stations and its storage in disused oil and gas wells underground

Question 8

What are the three stages of ‘carbon capture and storage’?

Answer 8

1. Separate CO2 from power station emissions
2. Compress and transport the CO2 using pipelines
3. Inject the CO2 into porous rocks deep underground

Question 9

How much could ccs reduce CO2 emissions by?

Answer 9

80-90%

Question 10

Example of a CCS project in the UK:

Answer 10

Drax Project in North Yorkshire
Designed to capture 2 million tonnes of CO2
Axed in 2016

Question 11

What are the limitations of CCS?

Answer 11

• Very expensive – Drax will cost at least £1 billion
• Uses large amounts of energy – 20% of a power plant’s output is needed to separate and compress
• Requires storage reservoirs with specific geological conditions