6.2 Climate change — causes and impactsIB Environmental Systems and Societies SL: Subtopic test

1. 1
   Scientists drill an ice core in Antarctica. As snow falls and compacts into ice, it traps tiny bubbles of air, so deeper layers are older. Analysis of the trapped air and of the ice itself shows that, over the last 800 000 years, periods with higher carbon dioxide concentrations match periods with higher temperatures.

   (a)

   Which part of the ice core provides information about the concentration of carbon dioxide in the atmosphere at the time the snow fell?

   [1 mark]

   • AThe thickness of each yearly layer of ice
   • BThe air bubbles trapped in the ice
   • CThe colour of the ice
   • DThe depth of the core below the surface

   (b)

   What does a positive correlation between carbon dioxide concentration and temperature mean?

   [1 mark]

   • AAs carbon dioxide concentration rises, temperature falls
   • BChanges in temperature never affect carbon dioxide concentration
   • CCarbon dioxide is the only factor affecting temperature
   • DAs carbon dioxide concentration rises, temperature tends to rise

   (c)

   Explain why scientists use ice cores, tree rings and deposited sediments together when studying past climates.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   In Alaska and northern Canada, warming has allowed shrubs and trees to spread northwards into areas that were open tundra, while the permafrost beneath the tundra is thawing. The Arctic is warming roughly three to four times faster than the global average. Tundra specialists such as the Arctic fox and the snowy owl live in the areas that are shrinking.

   (a)

   The spread of trees and shrubs into former tundra is an example of

   [1 mark]

   • Aa feedback loop
   • Becological succession caused by volcanic eruption
   • Ca biome shift
   • Dan increase in the resilience of tundra

   (b)

   Which statement correctly describes the resilience of an ecosystem?

   [1 mark]

   • AIts ability to return to its original state, or carry on functioning, after a disturbance
   • BIts total number of species
   • CIts ability to prevent any change at all
   • DIts mean annual temperature

   (c)

   Explain why the Arctic fox and snowy owl may be at risk as the tundra becomes warmer.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A student plots published data for the mean atmospheric carbon dioxide concentration measured at Mauna Loa, Hawaii: about 317 ppm in 1960, about 354 ppm in 1990 and about 414 ppm in 2020. In the planetary boundaries framework, the proposed safe boundary for atmospheric carbon dioxide is 350 ppm.

   (a)

   Calculate the mean annual rate of increase in carbon dioxide concentration for 1960 to 1990 and for 1990 to 2020, and state what your results show about the rate of increase and about the 2020 value.

   [3 marks]

   (b)

   Explain how feedback loops may affect the rate of global warming, using two examples and stating the type of feedback in each case.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Tuvalu is a Pacific island nation of low coral atolls whose highest point is only about 4.6 m above sea level. Its people rely on rainwater, groundwater, small-scale farming and fishing, and the national economy is very small. By contrast, the Netherlands has built extensive sea defences to protect land that lies below sea level.

   (a)

   Explain how climate change may reduce the resilience of a society such as Tuvalu.

   [6 marks]

   (b)

   Discuss how perspectives on climate change may differ between individuals and societies, referring to factors that influence them.

   [6 marks]

   Total for question 4: 12 marks

End of questions