ELSS 4.3 - How much change occurs over time in water and carbon?

How does increasing CO2 in the atmosphere create negative feedback?

• Increasing temperatures lead to wildfires

• Increasing temperatures stimulate greater photosynthesis

• Increasing temperatures lead to greater diffusion from the ocean surface

How does forestry modify the water cycle?

• Higher rates of rainfall interception

• Increased run-off and stream discharge

• Transpiration rates are increased

• Increasing the carbon storage in biomass

What are the interception rates for Sitka spruce like in Eastern England?

• As high as 60%

• As high as 50%

• As high as 40%

• As high as 30%

How does urbanisation alter the water cycle?

• Water storage capacity is reduced by impermeable surfaces

• Loss of biomass store due to deforestation and land clearance

• Drainage systems increase the rates of flows of water

How has water extraction from the River Kennet drainage basin affected the regional water cycle?

• Rates of extraction have exceeded rates of recharge - water table dropping has reduced flows 10-14%

• Increasing numbers of springs have formed in the chalk

• Lower flows have reduced flooding and temporary areas of standing water

What is the name for the height of the water table in areas of recharge on the edges of an artesian basin?

In what seasons does recharge tend to exceed extraction from aquifers?

• Spring

• Summer

• Autumn

• Winter

Today, CO2 levels in the atmosphere are the highest for at least...

• 800 years

• 8000 years

• 80,000 years

• 800,000 years

What are the issues with using carbon capture and storage to store carbon emissions?

• Involves large capital costs

• Uses large amounts of energy (20% of power plant output to separate and compress CO2)

• Requires storage reservoirs with specific geological conditions (impermeable cap)

• Liquified CO2 is injected into porous rocks deep underground

How do rising temperatures create positive feedback in the water cycle?

• Increasing evaporation leads to more water vapour (a GHG) in the atmosphere

• Increasing evaporation leads to more water vapour and condensation = greater cloud cover

• Trees respond to drought conditions by shedding leaves to avoid transpiration losses