4. Human impacts on carbon and water stores

Question 1

What human activities have caused changes in the availability of carbon and water?

Answer 1

• Urbanisation
• Fossil fuel emissions
• Deforestation
• Ocean acidification
• Irrigation and domestic usage of water
• Soil erosion

Question 2

Describe urbanisation:

Answer 2

• Reduced evapotranspiration that would naturally occur from vegetation = decline in precipitation
• Increased run-off (20-30% more) and reduced infiltration

Question 3

Describe fossil fuel emissions:

Answer 3

Removed billions of tonnes of carbon from geological stores

Question 4

Describe deforestation:

Answer 4

Reduces the carbon store in the biosphere and the carbon fixed by photosynthesis

Question 5

Describe ocean acidification:

Answer 5

Threatens the biological carbon store of the oceans and the carbon fixed by phytoplankton in photosynthesis

Question 6

Describe irrigation and domestic usage:

Answer 6

Created water shortages across the globe
Eg Colorado Basin in US = huge amounts of water evaporated from Lake Mead and Lake Powell
Eg Over pumping of aquifers in coastal areas of Bangladesh has made drinking water unsafe

Question 7

Describe soil erosion:

Answer 7

Due to deforestation and poor farming techniques has led to a decline in the carbon store of the soil