EQ2 Flashcards

Question

define positive feedback

Answer 1

a cyclical sequence of events that amplifies or increases changes

Answer 2

a cyclical sequence of events that damps down or neutralises the effect of a system

Answer 3

when a system changes from one state to another

Answer 4

the ability of a system to ‘bounce back’

Answer 5

Rainforests recycle half of their rainfall, but the positive feedback loop of deforestation + less rainfall is reducing the ability of the rainforests to regenerate → making the rainforest ecosystem less resilient

Answer 6

Reduced soil water storage Reduced evapotranspiration Changing weather patterns Lower precipitation

Answer 7

drought occurring more frequently

Answer 8

The amazon rainforests capacity to absorb carbon will decline Regional water cycles will change and soil temperatures will increase The amazon rainforest will be replaced with savannah-like grasslands More wildfires will increase the level of carbon in the atmosphere Reduced rainfall will threaten dependency on HEP (which generates 70% of its electricity) The world will lose a major carbon sink and source of moisture

Answer 9

vegetation will deteriorate due to decreased interception less infiltration and percolation to the ground water stores, causing the water table to fall Evapouration will continue and may increase due to less vegetation cover while transpiration rates will decrease, making wetlands less functional Dedication (the process of extreme drying) can also lead to wildfires

Answer 10

flooding that occurs after the ground has become saturated from prolonged heavy rainfall

Answer 11

flooding that occurs when intense rainfall has insufficient time to infiltrate the soil, so flows overland

Answer 12

a flood with an exceptionally short lag time - often minutes or hours

Answer 13

Especially in urban areas where ground is impermeable Small basins , especially in semi-arid/arid areas. Associated with very intense convectional storms Infiltration is limited with steep unvegetated slopes allowing overland flow to develop very quickly

Answer 14

Unusually heavy or prolonged rainfall Intense storms leading to flash flooding Extreme monsoonal rainfall Snow melt

Answer 15

The position of the jet stream causes flooding. Jet streams are the driving force which determine the direction of depressions and their high speeds.

Answer 16

Occasionally, dramatic floods occur following intense torrential storms. The intensity of the rainfall exceeds the capacity of the river to cope with amount of water → flooding occurs

Answer 17

Monsoon rains are often heavy, but in this case are larger low pressure systems brought heavier rain than usual. Occurs across south and southeast asia between May - Sept.

Answer 18

Flooding can occur when snow melts and the resulting water cannot infiltrate into the soil or ground surface.

Answer 19

A combination of economic growth and population movements have caused many floodplains to be built on and many natural landscapes to be modified for agricultural, industrial and urban purposes

Answer 20

Creation of impermeable surfaces – roofs, pavements, roads and car parking space. It has been estimated that in London, the land taken up by car parks is around 25 km^2 as around 60% of residents have paved over their front gardens for parking. Speeding up the drainage of water in built up areas via artificial conduits e.g drains and sewers Impeding channel flow by building alongside the river e.g building bridge supports and carrying out structural engineering by building levees Straightening channels (realignment) to increase the flow, which results in flooding downstream – this could be regarded as mismanagement in some ways. Resectioning by dredging involves widening and deepening the channel to increase efficiency by increasing capacity and moving water away at a faster rate – but at considerable environmental cost Changing land associated with agricultural development. Deforestation, overgrazing, ploughing or drowning wetlands usually occurs upstream from urbanised flood plains, which has a knock on effect downstream with increased run-off and increased levels of sediment (which are washed into rivers and block river channels)

Answer 21

Socioeconomic impacts: Floods cause death due to drowning or in certain countries poisonous snakes Water borne diseases, psychological stress can lead to post flood morbidity Direct structural damage to property in countries of all levels of development Post flood concerns over reduced property value when flood prone properties are resold Crops, livestock and agricultural infrastructure suffer major damage in rural areas Direct loss of food supplies = potential famine and also lead to rising food prices due to scarcity as crop shortages occur Loss of livelihoods as businesses due to flooding Areas reliant on tourism will suffer as people cancel holidays

Answer 22

Intense flooding caused by excessive overland flow can oversupply sediment and nutrients with possible eutrophication and the destruction of aquatic plants as wella s introducing pollution degrading aquatic habitats as wildlife is poisoned Environmental impacts There are some positives as natural ecosystems flood play an important role in maintaining biodiversity within ecosystems. Floods recharge groundwater systems, fill wetlands, increase connectivity between aquatic habitats, move sediment and nutrients → for some species floods trigger breeding, migration and dispersal

Answer 23

A consistent result across climate model projections is high precipitation extremes in warmer climates As temperatures rise so does the likelihood of precipitation falling as rain rather than snow increases A 4 inch sea level rise could double flooding frequency in many parts of globe - Catastrophic for communities and ecosystems - Eroding coastline worsens impacts E.g Hampshire village of Hambledon, underwater 6 weeks insurers estimated costs at £1bn Researchers found that the emissions increase odds of floods occurring

Answer 24

As precipitation intensity increases almost everywhere, especially mid to high latitudes, increases risk of flash and urban flooding → adapt storm drainage systems to accommodate inc rain intensity due to climate change Rapid melting of glaciers can lead to flooding of rivers + formation of glacial melt water lakes creating outburst flood The regions most at risk to increased flooding frequency is northern Europe

Answer 25

Climate change is likely to influence precipitation, temperature and potential evapotranspiration and through their combined effect, the occurrence and severity of drought In the past 30 years droughts have become more widespread, more intense and persistent – could it be due to human factors Research studies have proved inconclusive globally but southern Europe, south western America and the Sahel seem to have higher incidence and intensity of drought The occurrence of droughts seems to be determined largely by changes in sea surface temperatures, especially the tropics through changes in atmospheric circulation and precipitation amount Droughts can persist through a positive feedback where very dry soils and diminished plant cover can further suppress rainfall in an already dry area

Answer 26

Future Impacts: Rise in overseas risks for the UK as there's a rising need for military intervention → climate related migration and potential violent inter-state conflict over scarce resources Increased temperatures can amplify the impacts of drought, increased evaporation from soil → makes periodic droughts worse than what it would be under cooler conditions Early snow melt due to increased temperature can lead to water supply being increasingly out of phase with water demand Southwest america is considered one of the most sensitive regions in the world for increased risk of drought caused by climate change