EQ2

Question 1

Types of drought

Answer 1

• meteorological drought
• agricultural drought
• hydrological drought

Question 2

Meteorological drought

Answer 2

Dry weather patterns dominating an area

Question 3

Agricultural drought

Answer 3

Lack of moisture in surface soil 2 support plant life

Question 4

Hydrological drought

Answer 4

Occurs when there’s evidence of low water supply - reservoirs, streams, etc dry up

Question 5

Normal pacific conditions

Answer 5

Trade winds from east (Peru) to west (Australia)
Warm water pushes west
Upwelling, evaporation, rainfall over the pacific

Question 6

El Niño event

Answer 6

Trade winds weaken
Ocean current slows
Causing rainfall over S America

Question 7

La Niña event

Answer 7

Trade winds strengthen
Ocean currents + upwelling stringer
Rainfall over Australia (heavy rain, storms, flash flooding)
S America = droughts

Question 8

Impacts of drought on ecosystems

Answer 8

Wetlands
Forests

Question 9

Wetlands

Answer 9

10% of earths surface
Act as water stores, recharge aquifers + trap pollutants
Drought causes less interception, infiltration
Water table falls decreasing the functions performed by wetlands
Wetlands ar quite resilient- plants + soil can adapt well 2 human interference

Question 10

Forests

Answer 10

Forests are responsible for much of the worlds interception, reducing flooding + overland flow
Drought increases likelihood of fungal diseases in forest pines + threatens their survival
Forests are also resilient but are being tested by human interferences + erratic weather cycles

Question 11

Meteorological causes = flooding

Answer 11

1. Intense storms - w/ short lag time, common in mountainous areas
2. Prolonged heavy rain - monsoons/depressions over the UK
3. Rapid snowmelt - warmer seasons like Alaska

Question 12

Flooding is also increased by more general physical factors:

Answer 12

1. Topography (low-lying areas w/ impermeable surfaces)
2. Volcanic activity = jokulhlaups (ice forms at the top of the volcano + melts when it erupts - realising meltwater own the mountain)
3. Earthquake activity rupturing a dam/damaging of a reservoir releases water elsewhere

Question 13

Human actions + flooding

Answer 13

Channelisation: effective way of improving river discharge + reducing the flood risk. Trouble is that it simply displaces river downstream. Some other locations may well be overwheby increased discharge
Dams: block the flow of sediment down a river - reservoir gradually fills up with silt downstream there’s an increased river bed erosion
River embankments: designed 2 protect from floods of a given magnitude. Fail when a flood exceeds their capacity. Inevitably when this happens- scale of flooding is much greater

Question 14

Climate change - precipitation (input)

Answer 14

Warmer atmosphere holds more water
Impacts such as increasing rainfall intensity
Geographical area of precipitation increases in tropics + decreases above + below the tropics. Length + frequency of heatwaves increases

Question 15

Climate change - evaporation (output)

Answer 15

Areas such as Asia + N America see an increase = evaporation, transpiration generally increases too - affecting soil moisture

Question 16

Climate change: stores

Answer 16

Surface run-off: more low flows (droughts) + floods
Groundwater flow: uncertain because of abstraction by humans

Question 17

Climate change: flows

Answer 17

Reservoirs, lakes, wetlands - temp increases wetlands decreases in storage
Soil moisture - little change but more periods of drier + wetter weather
Permafrost - melting takes places which depends the active layer releasing methane
Snow + ice storage - glacial retreat + decreases in snow-cover seasons. Decreasing store overtime

Question 18

Uncertainty caused by CC

Answer 18

• increases in annual temp lead 2 greater evaporation from surface water + reservoirs in summer (discharge may Inc)
• greater rates = evapotranspiration + desiccation of forest stores
• impact of oscillations e.g. ENSO is leading 2 increasingly unreliable patterns of rainfall e.g. les predictable monsoons
• more frequent cyclone + monsoon events threaten water supplies intermittently
• increased intensity + frequency of droughts as a result of global warming + oscillation is issue 4 rainfed agriculturalists
• depleted aquifers lead 2 problems w/ groundwater
• decreasing rainfall in many areas as a result of global warming
• loss of snow + glaciers as a store threatens many communities in mountain areas e.g. Himalayas