CCEA GCSE Geography Unit 1 Theme C Our Changing Weather and Climate: measuring weather, depressions, anticyclones, extreme weather and climate change

What this theme demands

Our Changing Weather and Climate is the third of the four physical themes in Unit 1 Understanding Our Natural World, and is worth a quarter of the unit. It moves from the measurement of everyday weather, through the pressure systems that bring the changeable weather of the British Isles, to a single extreme event and finally to climate change, the long-term story. This overview ties the dot-point pages together and shows how the resource-based paper rewards each skill.

The building blocks of the theme

The theme builds from the everyday to the global.

• Measuring the weather. The seven elements and their instruments, the Stevenson screen, and reading synoptic charts and climate graphs.
• Air masses and depressions. The air masses reaching the British Isles, and how a depression forms at the polar front and brings an ordered sequence of weather.
• Anticyclones. High pressure, sinking air and settled weather, and the sharp contrast between summer and winter.
• Extreme weather. A named event, how it forms, its social, economic and environmental impacts, and the three Ps that reduce them.
• Climate change. Natural and human causes, the effects, and mitigation versus adaptation.

Weather versus climate: the spine of the theme

The single idea that runs through Theme C is the difference between weather (the short-term state of the atmosphere) and climate (the long-term average over about thirty years). The first half of the theme is weather: measuring it, and the depressions and anticyclones that change it from day to day. The second half is climate: a single extreme event and the long-term shift of climate change. Knowing which timescale a question is about keeps your answer on track.

The skills the paper rewards

Theme C tests all three assessment objectives. AO1 is the elements, instruments and the formation of pressure systems. AO2 is explaining the weather sequence of depressions and anticyclones and evaluating climate-change responses. AO3 is the skills: reading isobars on a synoptic chart for wind, and describing a climate graph with its rainfall bars and temperature line.

Check your knowledge

A mix of recall questions covering the whole theme. Attempt them, then check the solutions.

1. Name the instrument used to measure wind speed and the one used to measure wind direction. (2 marks)
2. Give two features of a Stevenson screen. (2 marks)
3. Which two air masses meeting form most depressions over the British Isles? (2 marks)
4. Describe the weather at a warm front. (2 marks)
5. Why does an anticyclone bring clear skies? (2 marks)
6. Why are winter anticyclones so cold at night? (2 marks)
7. State the minimum sea temperature needed for a tropical storm to form. (1 mark)
8. Give one human cause of climate change. (1 mark)
9. What is the difference between mitigation and adaptation? (2 marks)