Global Warming

Question 1

A1 scenario

Answer 1

Rapid economic growth, population peak then fall, substantial reduction in regional income disparity

Question 2

B1 scenario

Answer 2

Same as a1 but moves towards service and information economy

Clean and resource efficient technology

Question 3

Why is there uncertainty in the scenarios?

Answer 3

• complexity of atmosphere
• feedback loops misunderstood
• assumptions on rates of consumption, population growth

Question 4

Tipping point

Answer 4

Irreversible climate change

Question 5

North Atlantic conveyor - thermohaline circulation

Answer 5

Heat from tropics moves to poles - as water comes across Atlantic it cools - becomes more dense and saline
This leads to down welling and the cold water sinks, and moves back south as a deep water current

Question 6

Why has down welling weakened and the amount of water carried in circulation dropped 30%?

Answer 6

Rapid melting of ice sheets - fresh water
Increased discharge from rivers due to melting permafrost

Freshwater - dilutes ocean waters, reducing salinity and density, weakening down welling

Question 7

What would happen without thermohaline circulation?

Answer 7

North west Europe - plunge into deep freeze
Sea ice would form in winter
Shorter growing season

Question 8

Causes of warming in the Arctic

Answer 8

Ice albedo feedback
Large areas covered permanently or seasonally by snow
Snow and ice reflect most solar radiation
Global warming reducing snow and ice cover
Land and water absorb more radiation
Rising temperatures, more melting — positive feedback

Question 9

Impact of melting permafrost

Answer 9

• huge volumes of methane and co2
• irreversible
• vegetation and habitat change
• disruption to migrations
• damage to infrastructure
• destruction of traditional indigenous economies

Question 10

What is eustatic sea level rise?

Answer 10

Global sea level rise