Atmospheric circulation

1. Atmospheric circulation

2. Causes of Climate Change Natural causes have been responsible for most climate change during the majority of Earths history but human causes have had a greater impact over the last 250 years, particularly since the Industrial Revolution. Natural causes: Milankovitch cycles, solar variation, volcanism, surface impact (asteroids) Human causes: Increase in greenhouse gases – energy, industry, transport, farming

3. Evidence of Climate Change • Ice cores: layers of ice tell age, tiny air bubbles in ice indicate levels of carbon dioxide • Tree Rings: width of ring indicates colder/warmer/ drier climates • Historical sources: personal diaries, paintings and religious documents

4. Consequences of climate change • Sea levels rise: thermal expansion and ice melt (low lying island nations lost, flooded land, new sea defences needed, salt water contamination of farmland) • Increased temperatures (food production, spread of pests, water supply lose, habitats and biodiversity lose) • Extreme weather events

5. Explain one way the climate of the Earth can change because of natural causes (3 marks) The Milankovitch cycles are the natural changes to the Earth’s orbit. This impacts how much radiation we receive from the sun. When the Earth’s orbit is further from the sun it receives less radiation than normal so is colder. When the Earth’s orbit is closer to the sun it receives more radiation than normal, leading to warmer periods or global warming. Task 1

6. Explain one way the climate of the Earth can change because of natural causes (3 marks) Stated one way The Milankovitch cycles are the natural changes to the Earth’s orbit. This impacts how much radiation we receive from the sun. When the Earth’s orbit is further from the sun it receives less radiation than normal so is colder. When the Earth’s orbit is closer to the sun it receives more radiation than normal, leading to warmer periods or global warming. Explanation for how this impacts on the climate Further development of the point. Explanation of how the suns orbit changes the climate.

7. Explain one way the climate of the Earth can change because of natural causes (3 marks) The Milankovitch cycles are the natural changes to the Earth’s orbit. When the sun is closer to the Earth it receives more radiation so is warmer. Another way is through volcanism. Large volcanic eruptions eject huge volumes of ash and dust into the atmosphere which blocks out the sun. This answer would get 2 marks. One mark for naming the natural change and then a further mark for its explanation. In neither example does it fully explain how the method impacts on the climate. Also note that two methods are given here so only one would be credited.

8. Tropical storms What conditions are needed? • A source of moist, warm air, normally more than 26.5oC • Warm ocean water • Winds converging at the ocean surface, causing the air to rise • Formation away from the Equator so the Coriolis effect will cause the storm to rotate Measured using the Saffir-Simpson scale – there are 5 categories, 5 is the most damaging

9. Global distribution of tropical storms

10. Study Figure 1, which shows the global distribution of tropical cyclones. Suggest two reasons for the distribution of tropical cyclones shown (4 marks) Task 2 Tropical storms form in the tropics because they need warm moist water to form, with air temperatures of more than 26.5oC. High temperatures cause the air to rise, creating areas of low pressure. Tropical storms have strong rotating winds, caused by the Coriolis effect. This begins at 5oC of latitude north and south of the equator. The Coriolis effect causes the storm to rotate.

11. Study Figure 1, which shows the global distribution of tropical cyclones. Suggest two reasons for the distribution of tropical cyclones shown (4 marks) Tropical storms form in the tropics because they need warm moist water to form, with air temperatures of more than 26.5oC. High temperatures cause the air to rise, creating areas of low pressure. Tropical storms have strong rotating winds, caused by the Coriolis effect. This begins at 5oC of latitude north and south of the equator. The Coriolis effect causes the storm to rotate. reason explanation reason Following each reason identified there is also an explanation for why it would affect the distribution explanation

12. Impacts of tropical storms on people and the environment • High winds • Intense rainfall • Storm surges • Coastal flooding • Landslides

13. Vulnerability to tropical cyclones Physical vulnerability: coastal areas are much more at risk, island nations are low-lying Social vulnerability: areas of poverty (housing and other constructions are more easily damaged), access to clean water, food, shelter and medical care Economic vulnerability: access to weather predictions, coastal defences, established evacuation procedures and disaster response teams

14. Explain why some areas are more vulnerable to the impacts of tropical cyclones than others (4 marks) Coastal areas are more likely to be at risk from tropical storms. This is because they are likely to be low lying. Island nations such as the Philippines have low lying coastal areas. This makes them much more vulnerable to the impacts of storms. Task 3

15. Explain why some areas are more vulnerable to the impacts of tropical cyclones than others (4 marks) Coastal areas are more likely to be at risk from tropical storms. This is because they are likely to be low lying. Island nations such as the Philippines have low lying coastal areas. This makes them much more vulnerable to the impacts of storms. This is because low relief is at risk from high winds and storm surges created by the tropical cyclone. This could also make flooding of the area more likely. 2 more marks given in this response as further explanation is made

16. Explain why some areas are more vulnerable to the impacts of tropical cyclones than others (4 marks) Areas of poverty are more vulnerable to the impacts of tropical cyclones. This is because housing may not be of high standard and so they are more easily destroyed and damaged by the storm. They may also not be able to afford food and clean water following the storm. This means people are more likely to suffer and possible death rates would be higher. Task 4

17. Explain why some areas are more vulnerable to the impacts of tropical cyclones than others (4 marks) Point Areas of poverty are more vulnerable to the impacts of tropical cyclones. This is because housing may not be of high standard and so they are more easily destroyed and damaged by the storm. They may also not be able to afford food and clean water following the storm. This means people are more likely to suffer and possible death rates would be higher. Explanation. Note the words used to extend the answer further… So… this means…

18. Preparing and responding to tropical storms • Atmospheric pressure measurements – identifying storm surges to happen • Satellite tracking and radar – technology monitors formation of tropical cyclones • Communicating information – the government will order evacuations of people, construction of shelters, information on preparation for people, broadcasts on TV and radio • Rescue workers, food/clean water/ medical care provisions, repair and construction of damaged buildings

19. Plate boundaries Moves apart Less violent volcanic eruptions Moves towards each other Violent volcanic eruptions, earthquakes and tsunamis Moves past each other, opposite directions or at different speeds in the same direction Devastating earthquakes

20. Volcanoes Hot Spots: Formed away from plate boundaries. Formed when superheated melted rock rises to the service and melts the asthenosphere. The magma produced then rises through weaknesses in the crust.

21. Earthquakes: Key Words • Focus • Epicentre • Shock waves • Foreshocks • Aftershocks • Seismometer • Magnitude • Richter scale • Tsunami

22. Explain why the impacts of an earthquake differ in different levels of development (4 marks) A developed country is able to prepare for an earthquake more effectively. They can afford to train emergency services to rescue people and provide medical care following an earthquake. Consequently more people would survive and the number of deaths would be lower than a developing country. A developed country would also be able to prepare by building earthquake proof buildings. They have the technology and money needed to build stable buildings able to withstand an earthquake. This would reduce the number of collapsed buildings compared to a developing country. Task 5

23. Explain why the impacts of an earthquake differ in different levels of development (4 marks) Main reason given A developed country is able to prepare for an earthquake more effectively. They can afford to train emergency services to rescue people and provide medical care following an earthquake. Consequently more people would survive and the number of deaths would be lower than a developing country. A developed country would also be able to prepare by building earthquake proof buildings. They have the technology and money needed to build stable buildings able to withstand an earthquake. This would reduce the number of collapsed buildings compared to a developing country. The main reason is then developed with 3 further points to fully explain why the impacts differ Take note of the adverbials here which link and develop your ideas