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A Level Geography > Topic 5 - Water Cycle And Insecurity: EQ2 > Flashcards

Topic 5 - Water Cycle And Insecurity: EQ2 Flashcards

1
Q

What is a drought?

A

An extended period of deficient rainfall relative to the statistical multi average for a region

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2
Q

What’s famine drought?

A

Food deficit

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3
Q

What’s agricultural drought?

A

Soil moisture deficit

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4
Q

What’s hydrological drought?

A

Stream flow deficit

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5
Q

What’s meteorological drought?

A

Rainfall deficit

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6
Q

What are the 4 physical reasons for drought?

A

Global atmospheric circulation
Failing of the ITCZ
Blocking high pressures
El Niño Southern Oscillation (ENSO)

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7
Q

How does global atmosphere circulation cause drought?

A

The subtropical high pressure zone is created where air that has risen at the equator has called and so sinks to form a belt of high air pressure and hot, dry conditions. It has low annual rainfall and is usually areas which are mostly deserts or grasslands due to limited moisture

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8
Q

How does the failing of the ITCZ cause droughts ?

A

The ITCZ causes air to rise due to intense solar heating, leading to high ocean evaporation and alternating wet and dry seasons. In summer, it shifts north, increasing rainfall in regions like West Africa and South Asia. In winter, it moves south, affecting areas in South America and Central Africa.

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9
Q

How can blocking high-pressure cause droughts?

A

Blocking high pressures disrupt air movement, creating stable conditions with clear skies and reduced cloud formation. They block low-pressure systems, potentially causing weeks or months of drought in mid-latitude regions like the UK. Persistent anticyclones can make it worse

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10
Q

How does El Niño Southern Oscillation (ENSO) cause droughts?

A

ENSO disrupts global weather by shifting the ITCZ and altering atmospheric circulation. El Niño warms Pacific waters every 2-7 years, moving the jet stream south and east, causing floods and droughts. La Niña cools Pacific waters, raising the jet stream and bringing Arctic-like conditions.

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11
Q

What is the case study for 5.4?

A

Sahel (2012/2013)

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12
Q

What are the human causes of drought in the Sahel?

A

Over grazing by tribes
Deforestation for fuelwood
Increasing population
Wars
Increase in farming
Soil damage

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13
Q

Why do humans have an impact in Sahel?

A

Humans act as a positive feedback loop and enhancing its impact due to social economic conditions

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14
Q

What is resilience?

A

Is the capacity of an ecosystem to drought. It is the ecosystem ability to persist in its present state despite having a deficit of water

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15
Q

What is a wetland?

A

An area of marsh, fen, peatland saturated with water permanent or seasonally. This might be static-water , flowing, fresh or salt

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16
Q

Why are wetland important?

A

Provide vital habitats to many types of plants and animals, many of which are useful to humans.
Humans depend on wetland for recreational activities such as hunting, bird watching, fishing

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17
Q

How do droughts affect wetlands?

A

Droughts have a big impact on wetland ecosystems and this can cause loss of habitats and as soil moisture is reduced they can be soil erosion and organic soils may oxidise recent carbon into the atmosphere.
Affect food web

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18
Q

Why are forests important?

A

they have ecological function such as the carbon storage, nutrient cycle, water and air purification, and maintenance of wildlife habitat, so your preservation and species habitat. They are also good for timber, food, fuel, and bio products

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19
Q

How do droughts affect forests?

A

the dryer warmer conditions lead to vegetation drying out and becoming more flammable. This makes them not very resilient as it would be hard to stop the fire once they started in the forest

20
Q

What are the meteorological causes of floods?

A

Jet stream and low pressure weather
Monsoon (India)
Ice melt (Siberia)

21
Q

How does Jet stream and low pressure weather cause floods?

A

Sometimes high pressure blocks the jet stream and continually delivers low pressure after low pressure to one area as there is high pressure either side

22
Q

How does the monsoon in India cause floods?

A

The monsoon brings heavy rain over a short period of time due to moist winds condenses into rain and causes continuous rainfall

23
Q

How does ice melt in Siberia cause floods?

A

Siberian snow melt in the spring causes extensive flooding across interiors of Asia such as the River Ob. There is a quick transformation from winter to spring, frozen ground meaning no infiltration means rapid level.

24
Q

What is the case study for 5.5?

A

Cumbria floods in 2015

25
Q

what were the (physical primary) meteorological causes of the Cumbria floods in 2015

A

Position of Jet stream and low
Low pressure system
Orographic rainfall
Antecedent conditions and rainfall intensity
Historic flooding

26
Q

How did historic flooding events cause floods?

A

Storm Desmond brought 847 billion litres of rainfall over Cumbria

27
Q

How did the jet stream cause floods

A

It was over Columbia at the time of the rainfall and cause atmospheric river and focus on Columbia

28
Q

How does low pressure system cause floods

A

There was also a low pressure system over Columbia and this creates precipitation due to clouds

29
Q

How does orographic rainfall cause floods?

A

Cambria is in a mountainous area so this means orographic rainfall will be there and this happens frequently

30
Q

How does antecedent conditions cause floods

A

The rain occurred over a short period and just before that they had a storm a week before. High level of discharge

31
Q

What were the secondary causes of flooding in Cumbria?

A

The rock type was mostly impermeable
Steep slopes of mountain means water travelled faster to rivers
Ground was already saturated so water went straight to river

32
Q

What were the secondary human causes of Cumbria floods

A

More roads and impermeable rocks so more pressure on drains and made them overflow
Deforestation, overgrazing
Sheep farming means it’s hard for afforestation
Bad flood defences

33
Q

Worst social impacts of the flood

A

The united biscuits factory which is the city’s biggest employer closed for weeks so many had to go with no work
3000 homes were flooded in 2005 and over 5200 in 2015

34
Q

Economic impacts of the flood

A

the cost of the flooding was over £100 million in 2005, £270m in 2009 and £400-500m in 2015
house prices fell in flood risk areas

35
Q

Environmental impacts of the flood

A

rivers were filled with debris and contaminated with sewage and pollutants
The saturated grounds led to landslides

36
Q

Use worksheet for more data on the floods

A

.

37
Q

How does climate change have an impact on the hydrological system

A

Increasing anthropogenic greenhouse gas emissions
Increasing heat trapped in the atmosphere (enhanced global warming)
Increasing average air temperatures and sea surface temperatures

38
Q

Hydrological variables that climate change?

A

Precipitation input
Soil moisture
Evaporation
Permafrost
Snow
Ice

39
Q

How is the hydrological cycle changing in California?

A

Increased droughts
3 times as many wildfires than normal in 2014
Forecasts of mega-droughts lasting 30 years

40
Q

How is the hydrological cycle changing in The Sahel?

A

Decline of rainfall of up to 40% between 1950 and 1990
Rains are failing due to ITCZ

41
Q

What is re-greening?

A

Covering land with grass and trees, making it healthy again

42
Q

What are the benefits of re-greening?

A

Natural regeneration of water-retaining shrubs and trees
Low cost reforesting
Use of water-harvesting techniques e.g. Demi-lunes

43
Q

Why is there uncertainty about future flooding?

A

We don’t know exactly where it will get hotter (and by how much)

44
Q

How would climate change lead to more floods?

A

For every 1 degree of temperature rise, the amount of moisture that can be held in the atmosphere rises by 7%

Creates potential for heavier precipitation and floods

45
Q

What are some human influences on droughts?

A

Land use change
Rising population
Poor farming
Normal variability

46
Q

What are some sources of uncertainty when discussing future climate change projections?

A

Complexity of climate systems (teleconnections)
Natural short term oscillations - e.g. ENSO cycles
Biogechemical positive and feedback mechanisms
Incomplete set of data (not collected in all locations)

47
Q

How could water uncertainty lead to famine?

A

Not being able to adapt to different conditions may cause a famine

Additionally, people don’t know whether they need to adopt new strategies or not

A Level Geography (10 decks)

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