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  • Created by: Iskall
  • Created on: 25-09-18 19:47
What are sea surface temperature anomalies?
Sea surface temperature anomalies relate to how much temperatures of the sea surface, recorded at a particular time, differ from the long-term average. Anomalies may be positive or negative.
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What is a positive sea surface temperature anomaly?
A positive anomaly occurs when the observed temperature is warmer than the average.
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What is a negative sea surface temperature anomaly?
A negative anomaly occurs when the observed temperature is cooler than the average.
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Sea surface temperature anomalies are an important causal factor is short-term or long-term precipitation deficits.
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Temperature anomalies provide the key to which event in the Southern Pacific Ocean?
El Nino-Southern Oscillation (ENSO)
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How often do El Nino events usually occur?
Three to seven years
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For how long does an El Nino event usually last?
18 months
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In what way does the water temperature change in the Pacific Ocean during an El Nino year?
Cool water normally found along the coast of Peru is replaced by warmer water. At the same time, the area of warmer water further west, near Australia and Indonesia, is replaced by cooler water.
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What conditions does an El Nino year seem to trigger throughout the world and in which year? And what is the example to suggest this?
Dry conditions and usually in the second year. The monsoon rains in India and South East Asia often fail.
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What event may, but not always, follow an El Nino event?
La Nina
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What is a La Nina episode?
Build up of cooler than usual subsurface water in the tropical part of the Pacific.
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Which conditions can a La Nina event cause?
Severe drought conditions, particularly on the western coast of South America.
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What does desertification mean?
Desertification is the process by which once-productive land gradually changes into a desert-like landscape. It usually takes place in semi-arid land on the edges of existing deserts. The process is not necessarily irreversible.
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What desert is an example of desertification?
The Sahel
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What is the downward spiral of causes of desertification?
1. Changing rainfall patterns with rainfall becoming less reliable, seasonally and annually. The occasional drought year sometimes extends to several years. 2. The vegetation cover becomes stressed and begins to die, leaving bare soil. 3. The bare so
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What are the four human factors encouraging the over-abstraction of surface water from rivers and ponds, and of groundwater from aquifers?
Population growth: Puts pressure on the land to grow more food. Migrants fleeing from one disaster area help to make another. Overgrazing: Too many goats, sheep and cattle destroy the vegetation cover. Overcultivation: Intense use of marginal land ex
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In the Sahel, why have crops, livestock and homes been deliberately destroyed?
Frequent civil wars
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What is grey water?
Waster bath, shower, sink and washing water. It can be recycled, but not necessarily for human consumption.
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What is ecological resilience?
The capacity of an ecosystem to withstand and recover from a natural event (such as drought and flooding) or some form of human disturbance.
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What percentage of Earth's lands is covered by wetlands?
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What are the important functions of wetlands?
Acting as temporary water stores. Recharging of aquifers. Giant filters trapping pollutants. Providing nurseries for fish and feeding areas for migrating birds.
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What is the impact of drought on wetlands?
With less precipitation there will be less interception (as vegetation becomes stressed), as well as less infiltration and percolation. Water tables will fall. Evaporation will also increase. This, together with the decrease in transpiration, will re
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What are the meteorological causes of flooding?
Intense storms which lead to flash flooding, as in semi-arid areas but more commonly in mountainous areas. Prolonged, heavy rain, such as during the Asian monsoon and with the passage of deep depressions across the UK. Rapid snow melt during a partic
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What is flash flooding?
Flash flooding is distinguished but its exceptionally short lag-time. Often minutes or hours.
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What are the three major rivers in Bangladesh?
Ganges, Padma and Meghna
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What is a storm surge caused by?
A storm surge is caused by very low air pressure which raises the height of the high-tide sea. Strong onshore winds then drive the 'raised' sea towards the coast, often breaching coastal defences and flooding large areas.
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The likelihood of flooding is increased by what physical circumstances?
In low-lying areas with impervious surfaces, as in towns and cities. Where the ground surface is underlain by impermeable rocks. When ice dams suddenly melt and the waters in flacial lakes are released. Where volcanic activity generates melt water be
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What are the human activities increasing the risk of flooding? 12
Grazing animals trample soil. Ploughing compacts soil. Streams channelled into culverts to aid rapid drainage of farmland. Dams built to supply towns with water. Sprinkling of groundwater on to arable crops. Wells sunk to supply settlements. Impermea
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What is channelisation and what is the problem with it?
An effective way of improving river discharge and reducing the flood risk. The trouble is that it simply displaces that risk downstream. Some other location may well be overwhelmed by the increased discharge.
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What is the problem with dams?
Block the flow of sediment down a river so the reservoir gradually fills up with silt; downstream there is increased river bed erosion.
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What are river embankments and what is the problem with them?
Designed to protect from floods of a given magnitude. They can fail when a flood exceeds their capacity. Inevitably, when this happens, the scale of the flooding is that much greater.
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What are the socioeconomic impacts of flooding?
Death and injury Spread of water-borne diseases Trauma Damage to property, particularly housing. Disruption of transport and communications. Interruption of water and energy supplies. Destruction of crops and loss of livestock Disturbance of everyday
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What are the environmental impacts of flooding?
Recharged groundwater stores Increased connectivity between aquatic habitats Soil replenishment For many species, flood events trigger breeding, migration and dispersal.
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What is eutrophication?
Eutrophication is the process of nutrient enrichment that ultimately leads to the reduction of oxygen in rivers, lakes and ponds, and the consequent death of fish and other species.
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What can the removal of soil and sediment by floodwaters lead to?
Eutrophication of water bodies.
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In what years did the UK experience severe floods?
2007 2015-16 winter
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What was the basic cause of the severe floods in the UK?
Prolonged rainfall.
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What two towns were among the worst-hit places and were the focus of media attention?
Carlisle and Cockermouth
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What are the impacts of climate change on precipitation?
A warmer atmosphere has a greater water-holding capacity. It is argued that the mode of precipitation may be more important than the amount in determining the impacts. Widespread increases in rainfall intensity are expected more than large increases
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What are the impacts of climate change on evaporation and evapotranspiration?
Evaporation over large areas of Asia and North America appears to be increasing. Transpiration is linked to vegetation changes, which in turn are linked to changed is soil moisture and precipitation.
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What are the impacts of climate change on soil moisture?
Uncertain, as soil moisture depends on many factors, of which climate is only one. Where precipitation is increasing, it is likely that soil moisture will also increase.
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What are the impacts of climate change on surface runoff and stream flow?
More low flows (droughts) and high flows (floods) Increased runoff and reduced infiltration
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What are the impacts of climate change on groundwater flow?
Uncertain, because of abstraction by humans
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What are the impacts of climate change on reservoir, lake and wetland storage?
Changes in wetland storage cannot be conclusively linked to climate change. It appears that storage is decreasing as temperatures increase.
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What are the impacts of climate change on permafrost?
Deepening of the active layer is releasing more groundwater. Methane is released from thawed lakes may be accelerating change.
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What are the impacts of climate change on snow?
Decreasing length of snow-cover season Spring melt starting earlier A decreasing temporary store
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What are the impacts of climate change on glacier ice?
Strong evidence of glacier retreat and ice sheet thinning since the 1970's. Less accumulation because more precipitation falling as rain. A decreasing store.
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What are the impacts of climate change on oceans?
More data on surface temperatures needed. Where there is ocean warming, there will be more evaporation., Possibly ocean warming leads to the generation of more cyclones. Storage capacity being increased by meltwater Rising sea level.
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When does water insecurity begin?
Water insecurity begins to exist when available water is less than 1,700m3 per person per day. This marks the start of what is known as water stress. Below 1,000m3 per person per day, water stress gives way to water scarcity.
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What is absolute water scarcity?
Available water is between 0 and 500m3 per person per day.
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What is water scarcity?
Available water is between 500 and 1000m3 per person per day.
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What is water stress?
Available water is between 1000 and 1700m3 per person per day.
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What is water vulnerability?
Available water is between 1700 and 2500m3 per person per day.
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What are the human and physical factors that reduce the amount of water that is eventually available for human use?
Evaporation and evapotranspiration Discharge into the sea Saltwater encroachment at the coast Contamination of water by agricultural, industrial and domestic pollution. Over abstraction from rivers, lakes and aquifers and the acute need to replenish
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The rising water demand for water is driven by which three main factors?
Population growth Economic development Rising living standards
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How does population growth raise water demand?
More people. more thirsts to quench.
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How does economic development raise water demand?
Increases the demand for water in almost all economic activities- agriculture, industry, energy and services. One of the biggest and fastest-growing consumers is irrigation.
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How does rising living standards raise water demand?
Increase in the per capita consumption of water for drinking, cooking, bathing and cleaning. Added to this domestic consumption are water-extravagant things such as swimming pools, washing machines and dishwashers.
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Other cards in this set

Card 2


A positive anomaly occurs when the observed temperature is warmer than the average.


What is a positive sea surface temperature anomaly?

Card 3


A negative anomaly occurs when the observed temperature is cooler than the average.


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Card 4




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Card 5


El Nino-Southern Oscillation (ENSO)


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