Atmosphere and climate changeIB Environmental Systems and Societies SL: Topic test

1. 1
   The Sahara Desert, in northern Africa, lies at about 30° north of the equator, and the Atacama Desert in South America lies at about 25° south. Both are among the driest places on Earth. At the equator, in contrast, rainforests receive heavy rainfall all year. Climate scientists explain this pattern using the tricellular model of atmospheric circulation, which shows how heat is redistributed from the equator towards the poles.

   (a)

   Why is the air at the equator rising?

   [1 mark]

   • AIt is heated strongly by the Sun, so it becomes less dense and rises
   • BIt is cooled by the oceans and becomes less dense
   • CIt is pushed upwards by air sinking at the poles
   • DIt is attracted by the Moon

   (b)

   Which statement explains the dry conditions at about 30° north and south?

   [1 mark]

   • AMoist air is rising there and losing its water as rain
   • BWinds blow from the poles carrying very cold, dry air
   • CCool air is sinking there, warming as it falls, so cloud and rain are unlikely
   • DThere is no atmospheric circulation at this latitude

   (c)

   Explain how the tricellular model helps to redistribute heat on Earth.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   In a desert region the air temperature is 40 °C by day but falls to 8 °C at night under a clear sky. In a humid coastal city at the same latitude, the day temperature is 33 °C and the night temperature falls only to 27 °C. The Sun emits mostly short-wave radiation, which passes through the atmosphere and warms the ground. The warmed ground gives out long-wave infrared radiation.

   (a)

   Which gas in the humid air is the most abundant greenhouse gas?

   [1 mark]

   • AOxygen
   • BWater vapour
   • CNitrogen
   • DArgon

   (b)

   What happens to infrared radiation emitted from the ground?

   [1 mark]

   • AAll of it passes into space
   • BAll of it is reflected by the ozone layer
   • CIt is converted into short-wave radiation by clouds
   • DSome is absorbed and re-emitted by greenhouse gases, including back towards the surface

   (c)

   Explain why the night temperature in the humid coastal city is much higher than in the desert.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   Country R is a fast-growing economy. In 1990 its carbon dioxide emissions were 600 million tonnes and its population was 40 million. By 2020 its emissions had risen to 1050 million tonnes and its population had risen to 70 million. Country R is a large country with a long coastline and many people living on low-lying river deltas, as well as in cities. It has a lower income than many of the highest-emitting countries.

   (a)

   Calculate the percentage increase in Country R's total emissions between 1990 and 2020, and its emissions per person in 2020.

   [3 marks]

   (b)

   Discuss how the impacts of climate change may differ between a high-income country and a low-income country.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Satellite images show that the area of Arctic sea ice at the end of summer has shrunk by more than 10% per decade since the late 1970s. Sea ice is white and reflects most of the Sun's radiation back into space, while the dark ocean absorbs most of it. The ice is a hunting platform for polar bears and seals, and the base of a food web that begins with algae living on the underside of the ice. Inuit communities use the ice for travel and hunting, and ships are beginning to use new sea routes.

   (a)

   Explain how the loss of Arctic sea ice can lead to a positive feedback loop that increases global warming.

   [6 marks]

   (b)

   Evaluate the impacts of the loss of sea ice on ecosystems and societies in the Arctic.

   [6 marks]

   Total for question 4: 12 marks

5. 5
   Sweden introduced a tax on carbon dioxide emissions from fossil fuels in 1991. The tax has been raised several times and is now one of the highest in the world. Sweden has also generated more of its electricity from hydropower, nuclear power and wind. Its greenhouse gas emissions have fallen by about a third since 1990, while its economy has grown. Even so, Sweden accounts for only a tiny share of global emissions, and climate scientists say that global emissions need to fall rapidly.

   (a)

   Why is the carbon tax a mitigation strategy?

   [1 mark]

   • AIt helps people cope with the effects of warming
   • BIt removes carbon dioxide from the atmosphere directly
   • CIt gives users a financial incentive to reduce greenhouse gas emissions
   • DIt makes fossil fuels cheaper

   (b)

   What does decarbonisation of an economy mean?

   [1 mark]

   • AReducing or ending the use of energy sources that emit carbon dioxide and replacing them with low-carbon sources
   • BRemoving all carbon from living things
   • CBurning fossil fuels more efficiently only
   • DIncreasing the use of coal for electricity

   (c)

   Explain why global action is needed to avoid catastrophic climate change, even though one country such as Sweden has reduced its emissions.

   [2 marks]

   Total for question 5: 4 marks

6. 6
   The Netherlands is a densely populated country, and about a quarter of it lies below sea level. Its Room for the River programme has lowered floodplains and moved some dykes back from rivers, so that rivers can flood safely in some areas when water levels are high. In Rotterdam, car parks and public squares have been designed so that they can store rainwater during heavy storms. The national government also regularly updates its plans for flood defences using predictions of future sea-level rise.

   (a)

   Which of these is an adaptation strategy?

   [1 mark]

   • AReplacing coal power stations with wind farms
   • BTaxing vehicles that emit carbon dioxide
   • CPlanting new forests to absorb carbon dioxide
   • DLowering a floodplain so that a river can overflow safely

   (b)

   What is the purpose of a National Adaptation Programme of Action (NAPA)?

   [1 mark]

   • ATo set a global limit on carbon emissions
   • BTo identify a country's priorities for coping with the effects of climate change
   • CTo stop a country from using fossil fuels
   • DTo measure the amount of greenhouse gas in the air

   (c)

   Distinguish between mitigation and adaptation in responding to climate change.

   [2 marks]

   Total for question 6: 4 marks

7. 7
   A research station near the South Pole records the mean total amount of ozone above it each October, in Dobson units (DU). The figures below are simplified for this question. In 1975 the mean was 320 DU. In 1990 it was 190 DU. In 2020 it was 260 DU. Between 1975 and 1990 the concentration of ozone-depleting substances in the stratosphere rose sharply, and after the year 2000 it slowly began to fall.

   (a)

   Calculate the percentage fall in ozone between 1975 and 1990, and the percentage of this fall that had been recovered by 2020.

   [3 marks]

   (b)

   Explain the effects of reduced stratospheric ozone on living organisms.

   [4 marks]

   Total for question 7: 7 marks

8. 8
   Norway is a wealthy country that earns a large share of its income from exporting oil and gas. At the same time, nearly all of its electricity comes from hydropower, and more than 80% of the new cars sold there are electric, helped by tax exemptions and the construction of public charging points. Some Norwegians believe the country should stop producing oil because of climate change. Others say that Norway has the right to use its resources, as other countries do, and that its exports will be needed for a long time.

   (a)

   Explain why individuals and societies can hold different perspectives on climate change.

   [6 marks]

   (b)

   Evaluate Norway's strategies for responding to climate change.

   [6 marks]

   Total for question 8: 12 marks

End of questions