EQ3 6.7

Question 1

How has the biosphere changed due to human activity?

Answer 1

• 30% of global forest cleared, 20% degraded
• For commodity production (e.g., soy, palm oil, beef, paper)
• For land conversion (e.g., dams, reservoirs, infrastructure, mining)
• Technology increases efficiency but consumer behavior matters
• Energy use ↑ 54%, population ↑ 36%
• Developed countries use 50% of world energy
• Biggest increase in SE, S, and E Asia

Question 2

How does the biosphere impact the water cycle?

Answer 2

• Transpiration from vegetation to air
• Vegetation slows SRO + through flow
• Vegetation = interception of rainfall = evaporation
• Roots = increased percolation
• Organic matter = increased amount of moisture stored in soil

Question 3

How does the biosphere impact soil health?

Answer 3

• Decomposing vegetation releases nutrients into soil

Vegetation provides:
* Humus for soil
* Erosion protection
* Nitrogen fixation

Question 4

How does the biosphere impact the carbon cycle?

Answer 4

• Photosynthesis: takes in CO₂, emits O₂
• Vegetation = carbon sink
• Forest fires release trapped carbon
• Dry soils emit CO₂
• Wet soils store 3x more carbon than vegetation
• Decomposition slows with water loss

Question 5

What management strategies reduce biosphere impacts?

Answer 5

• IPCC recommendations: low-emission food crops, reduced food waste, dietary changes
• Avoid disturbing peat soils
• Restore degraded soils
• Afforestation fallow periods (periods of not growing anything to improve soil quality)
• Beware monoculture: less carbon stored, more water used, disease risk

Question 6

What environmental issue is the Great Green Wall in Africa aiming to combat?

Answer 6

Desertification caused by the expansion of the Sahara Desert

Question 7

Which country has made the most progress in the Great Green Wall project?

Answer 7

Senegal

Question 8

What is the Green Wall of China officially called?

Answer 8

The Three-North Shelterbelt Program

Question 9

Why was the Green Wall of China started?

Answer 9

To stop the spread of the Gobi Desert due to deforestation and land degradation

Question 10

When did the Green Wall of China project begin and when is it expected to finish?

Answer 10

• Began in 1978
• Aims for completion by 2050

Question 11

What is ocean acidification?

Answer 11

• Sea is a carbon sink so absorbs CO2
• Creates weak carbonic acid (ocean becomes less alkaline)

Question 12

How does ocean acidification cause bleaching?

Answer 12

• Carbonic acid reacts with carbonate ions = increased no. of bicarbonate ions
• Reduced carbonate ions needed for CaCO3 shells so corals (i.e. phytoplankton) need more energy to build shells - become thinner/fragile
• Also, increased acidic water = shells dissolve

Question 13

Ocean acidification positive feedback loop?

Answer 13

• Ocean acidification = decreased dimethyl sulphide from phytoplankton = reduced sulfur in clouds = reduced cloud condensation nuclei = reduced cloud cover = reduced sunlight reflection

Question 14

Climate change impacts on atmosphere and hydrosphere processes?

Answer 14

• Water cycle changes
• Soil moisture changes
• Increased water supply insecurity
• Increased frequency of drought due to shifting climate belts

Question 15

Climate change impacts on biosphere processes?

Answer 15

• Water stress = forest health deterioriates