Water and Carbon Cycles

What Water and Carbon Cycles covers

Water and Carbon Cycles is examined in A2 Unit 3, Global Systems and Global Governance. It covers the water cycle as a global system and mass balance, global water stores and residence times, Cryospheric processes and sea-level change, drainage basin inputs, stores and outputs, flows within the drainage basin, river regimes and their controls, storm hydrographs and hydrograph shape, air uplift, cloud formation and precipitation, excess runoff and flooding, deficit in the water cycle and aquifer recharge, the global carbon cycle and its stores, carbon pathways between land and the atmosphere, carbon transfers involving the oceans, carbon stores in biomes and land-use change, changing carbon stores in peatlands, rising atmospheric carbon and its impacts and feedback within and between the water and carbon cycles.

The 17 subtopics

Each one has its own page.

• The water cycle as a global system and mass balanceDescribing the water cycle as a system, store and a flow and two forms of energy that drive the water cycle.Open →
• Global water stores and residence timesLargest single store of fresh water on Earth, approximate residence time of water in the atmosphere and fossil water.Open →
• Cryospheric processes and sea-level changeAccumulation in a glacier system, mass balance of a glacier and negative mass balance.Open →
• Drainage basin inputs, stores and outputsDrainage basin, difference between the amount and the intensity of precipitation and held in the interception store.Open →
• Flows within the drainage basinInfiltration capacity, how infiltration-excess overland flow is generated and how saturation-excess overland flow is generated.Open →
• River regimes and their controlsRiver regime, river with a simple regime and state its control and typical regime of a British lowland river.Open →
• Storm hydrographs and hydrograph shapeStorm hydrograph, lag time and peak discharge.Open →
• Air uplift, cloud formation and precipitationThree main causes of air uplift, how orographic rainfall forms and rain shadow.Open →
• Excess runoff and floodingExcess runoff, how prolonged precipitation causes flooding and monsoon and its effect on runoff.Open →
• Deficit in the water cycle and aquifer rechargeWater deficit, how seasonal variation produces a soil moisture deficit and two rock types that make good aquifers in Britain.Open →
• The global carbon cycle and its storesFour main carbon stores on Earth, approximate size of the ocean carbon store and carbon sequestration.Open →
• Carbon pathways between land and the atmosphereWord equation for photosynthesis, respiration in terms of the carbon cycle and how burning fossil fuels moves carbon between stores.Open →
• Carbon transfers involving the oceansSolubility pump of the oceans, biological pump and absorption of carbon by marine biota.Open →
• Carbon stores in biomes and land-use changeWhy temperate grassland soils accumulate so much carbon, three ways in which deforestation reduces a carbon store and how afforestation increases a carbon store.Open →
• Changing carbon stores in peatlandsHow peat forms, roughly how fast peat accumulates and plant most associated with the building of British blanket bog.Open →
• Rising atmospheric carbon and its impactsHow carbon dioxide alters the Earth's energy budget, radiative forcing and how warming intensifies the water cycle.Open →
• Feedback within and between the water and carbon cyclesPositive feedback, negative feedback and threshold in a natural system.Open →

What you need to know

Answer each one before you reveal it.

Take Water and Carbon Cycles further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Infiltration vs Percolation

  Infiltration: the entry of water from the surface into the soil. Percolation: the continued downward movement of that water from the soil into the rock beneath.

• River regime vs Storm hydrograph

  River regime: the pattern of a channel's discharge across a whole year, showing its seasonal variation. Storm hydrograph: the pattern of discharge over the hours and days following a single rainfall event.

• Potential evapotranspiration vs Actual evapotranspiration

  Potential evapotranspiration: the amount of moisture that would be returned to the air if the supply were unlimited. Actual evapotranspiration: the amount that is genuinely returned, limited by how much moisture is available.

Questions from this topic

Each one with the model answer underneath.

1. 1

   What is meant by describing the water cycle as a system?

   Model answer

   It is a set of stores linked by flows, so that water moves between them under an input of energy and a change in one part of it forces a change elsewhere.

2. 2

   Name the four components used to describe any part of the water cycle.

   Model answer

   Inputs, outputs, stores and flows, with flows also called transfers.

3. 3

   Why is the global water cycle described as a closed system?

   Model answer

   Almost no water enters or leaves the planet, so the total quantity stays effectively fixed and only its distribution between stores changes.

4. 4

   Explain why a drainage basin is an open system when the global cycle is closed.

   Model answer

   A drainage basin gains water as precipitation from outside its boundary and loses it as river discharge and evapotranspiration, whereas the planet as a whole neither gains nor loses any significant amount of water.

5. 5

   Define the term mass balance as it is used in the water cycle.

   Model answer

   Mass balance is the principle that over a given period the inputs to a store equal its outputs plus or minus the change in the amount held in that store.

6. 6

   What happens to a store when its inputs exceed its outputs?

   Model answer

   The store grows, because the surplus water is added to the amount already held there.

What is inside Levo

Six ways to work the same material.

Water and Carbon Cycles revision questions

What does Water and Carbon Cycles cover in WJEC A-Level Geography?

17 subtopics: the water cycle as a global system and mass balance, global water stores and residence times, cryospheric processes and sea-level change, drainage basin inputs, stores and outputs, flows within the drainage basin, river regimes and their controls, storm hydrographs and hydrograph shape, air uplift, cloud formation and precipitation, excess runoff and flooding, deficit in the water cycle and aquifer recharge, the global carbon cycle and its stores, carbon pathways between land and the atmosphere, carbon transfers involving the oceans, carbon stores in biomes and land-use change, changing carbon stores in peatlands, rising atmospheric carbon and its impacts and feedback within and between the water and carbon cycles. Each one has its own page with questions and model answers.

How is Water and Carbon Cycles organised?

By the WJEC 601-8455-3 specification, subtopic by subtopic, so it matches the order you are taught it in.