Water edexcel alevel geography

describe physical distribution of water?

- uneven physical distribution (66% of the population has access to 25% of the annual rainfall, 60% of water supplies are in only 10 countries)

what are the reasons for the gap between rising demand and diminishing supplies in water?

Despite there being 37% of fresh water reserves unused, there is a diminishing availability of finite supplies and a rising demand.

- population growth + rising middle class = rising demand and dwindling supply (e.g. as china adopts a more meet rich diet from inc. middle class, more water is needed for agriculture)

- economic growth increases demand in all economic sectors , e.g. energy need mining of unconventional services, e.g. fracking.

- irrigation in countries boardering the Aral Sea, 99% of water is used for irrigating crops = drought, env. degradation.

what are the 3 water pressure points?

- diminishing supply (impact of climate change, worse quality from pollution)

- rising demands (population growth, economic development)

- competing demands from users (internal conflicts in a basin, upstream and downstream issues from HEP and irrigation)

what is the water availability gap?

- imbalance of usage, richer countries us 10x more per head

- this is due to embedded (virtual) water - hidden flow of water use in food and commodities when traded, and direct water

what is water stress?

when water resources are between 1,000 and 1,700m3 per capita. Causes restrictions on water use, tensions, conflicts, declining standards of reliability and service, harvest failures and food insecurity. (Pakistan, Iran)

what is water scarcity?

occurs when a country's renewable water resources are low (500 to 1,000 m3 per capita). Symptoms - unsatisfied demand, open tension and conflict, competition for water, over-extraction of groundwater, and insufficient flows to the natural environment. (the edge of North Africa, the Middle East). It occurs when more than 75% of a country/region's blue water flows (rivers, lakes, seas) are being used. This applies to 25% of the worlds population.

what is absolute water scarcity?

- renewable water resources are below 500m3 per capita. Causes widespread restrictions on water use and rationing.

How does the UN describe water security?

'The capacity of a population to safeguard sustainable access to adequate quantities of acceptable quality water for sustaining livelihoods, human wellbeing and socio-economic development, for ensuring protection against waterborne pollution and water-related disasters, and for preserving ecosystems in a climate of peace and political stability'

What is water insecurity?

When the economic, environmental and social criteria of water security are not met, or only partially.

E.G.:

- Water use has been growing by more than twice the rate of population increase in the last century.

- By 2025, 1.8 billion people will be living in countries or regions with absolute water scarcity, and 2/3 of the world will be under water stress conditions.

define physical scarcity and economic scarcity of water

physical - when over 75% of blue water is used in a country (25% of population)

economic - development of blue water sources is limited by lack of capital, technology and good governing.

How is Precipitation a physical cause of water scarcity?

macro scale - climate determines distribution of earths water.

- varies globally due to atmospheric pressure systems

- annual and seasonal variability

- distribution, reliability and intensity of precipitation determine water supply availability

influenced by short-term climate changes, e.g. ENSO and climate warming

How is topography a physical cause of water scarcity?

regional scale - high relief has more precipitation and faster run-off.

when combined with impermeable geology = better surface storage in natural lakes or reservoirs.

locally - snowfall and glaciers affect cryosphere storage and alter water supplies

How is river flows a physical cause of water scarcity?

- they store large quantities of water, e.g. Amazon has annual discharge of 175,000 cubic meters per second.

- Droughts can cause less flows which means less water storage (Brazil, 2005)

How is geology a physical cause of water scarcity?

- controls distribution of aquifers

- permeable chalks and porous sandstone store water well (not affected by evaporation as underground)

- wells and natural springs

how is pollution a human factor influencing the security of water supplies?

- affects surface and ground water = knock on effect on security of supplies

- widespread globally, most significant in developing countries (1 billion have no safe water)

- altered by a countries ability to act in prevention and remediation

how is pollution affecting china?

- 300 million daily use contaminated water

- 1/3 of all rivers + 75% of lakes are classified as highly polluted

- future possible that waterborne disease may affect 2 million

- contaminated by run-off from sewage

how is groundwater pollution a human factor influencing the security of water supplies?

- irreversibly damages aquifers

- 20% in Bangladesh by arsenic

- causes health problems = social problems

- 137 million world wide in 70+ countries have arsenic poisoning from drinking water

causes of water pollution include:

- untreated sewage disposal = typhoid, cholera.

- chemical fertilisers - contaminate ground and river water = eutrophication = hypoxia and dead zones in coastal water

- industrial waste dumped - heavy metals

- 60% of worlds rivers are embedded by damns

how is over abstraction a human factor influencing the security of water supplies?

for domestic, agriculture and industrial use.

- removal of freshwater from coastal aquifers disrupts natural balance saline + fresh water. = salt water incursion and salinisation.

- agriculture and industry require lots of water (used to be 70% of global extractions for farming)

- biofuels and fracking, new energy developments that require lots of water

KEY CONCEPT - water poverty index

assessment of the degree of water shortage and the subsequent water insecurity problems.

uses 5 perameters

1. resources

2. access

3. capacity

4. use

5. environemnt

each scored out of 20, so overall score can reach 100.

- highest scoring country is Finland (with a score of 78), Haiti has lowest score of 35.

What causes the global pattern of water scarcity?

- access to water (e.g. poverty or areas where technology/capital investment is needed to overcome shortage)

- availability of water (as well as supply, a water distribution network is needed)

- usage of water (entitlement and understanding)

what is the economic gap that causes water scarcity?

There is a significant difference in water use across the development divide, as water is more expensive in developing countries.

For example, in the Slums of Dar es Salaam, the cost of water is $8, While Tap water in Dar es Salaam costs $0.34, UK tap water $1.62, and USA tap water $0.68.

what determines the price of water?

- physical cost of obtaining supply

- the degree of the demand of water, when more scarce the price increases

- insufficient infrastructure in the developing world

- who supplies water e.g. in developing countries water is free but not treated, in developed worlds water is privatised and has a mark up.

why is the price of water increasing?

- privatisation sees water as a commodity in which profits should be made.

- in developing countries the IMF and WB set up a structural adjustment program to try and help the countries out of debt. Privatisation in this was essential as Current systems were failing to provide water to poor citizens.

- developing world governments made contracts with international water companies/ TNCs e.g. Suez

- providing water in difficult conditions meant huge price increases

- challenging to develop reasonable water prices in developing countries.

why is water important for economic development - agriculture

- Agriculture dominates water use; about 3,770 kilometres of water are withdrawn each year

- agriculture absorbs 2/3 of water extractions globally

- 1/5 of worlds land is under irrigation

- water for irrigation comes from dams - irrigated canals, causes waterlogged land + salivation of soil. OR pumped electrically from aquifers, depleting groundwater (India, China etc)

why is water important for economic development - Industry and energy

- 20% of all freshwater withdrawals worldwide are for industrial and energy production.

- 40 - 50% in developing countries

- used for companies in chemicals, electronics, paper, petroleum and steel are major consumers of water.

- rapid industrialisation has caused pollution in lakes and rivers - TNCs try and reduce consumption e.g. Coca Cola in India

- use in energy for:

50% HEP

cooling of thermal and nuclear power stations

- in these cases it is returned to the stores unchanged (except the warmth which can cause bacteria in water)

why is water important for economic development - human well being

Rising standards of living and an increasing per capita consumption of water. Safe water is a human need.

- water and disease interlink, can prevent and cause.

- 10% of global disease burden is due to lack of sanitation - poverty is most important factor

- often improving programs of water hygiene in a community is more key than acute water shortage - disease due to unclean water causes high morbidity = affects people ability to work or cook = harder to escape poverty

- vectors caused by stagnant water (reservoirs behind dams provide this)

- polluted water can cause infection when washed in

Why does water insecurity increase conflict?

(3 pressure points of water)

when demand for water outruns supply + the multiple players use the same diminishing supply = potential for conflict at all scales.

- usually caused when upstream countries alter the flow of water for downstream countries. (quantity of water)

what is and causes transboundary conflict?

- When a river, lake or aquifer crosses one or more political borders.

· 40% of the population lives within a river or drainage basin that extends over two or more countries.

· The 263 transboundary accounts for 60% of the world's drinking water.

· 2 billion people worldwide depend on groundwater, which includes around 300 transboundary aquifer systems.

What triggers transboundary water conflict?

- Reduced river discharge due to upstream diversion/extraction

- Mega-dams, which regulate the flow

- Pollution discharge that makes the water unusable

- Groundwater abstraction that reduces the water table of a transboundary border

Explain conflict over groundwater sources

- subterranean aquifers cross international boarders. usage is complex because:

- supplies are underground so it takes years to see the effects of usage

- hard to tell boundaries underground so hard to negotiate equal share

- UN legislation on aquifer sharing is only beginning to appear

types of water conflict

- International, i.e. diplomatic 'spats' to all-out war (rare)​

- Internal local, i.e. between players/users in one area​

- Internal regional, e.g. China's South-North transfer ​

name some international hotspots of potential water conflict?

- Major tensions over the River Jordan and River Litani and the aquifers under Israel and Palestine.

- The Murray / Darling basins. Salinisation of farmland, drought - area produces three-quarters of Australia's irrigated crops. ​

- Mexico City is now at serious risk of running out of clean water. 40% of the city's water is lost through leaky pipes built at the turn of the century.

what are the two different approaches to managing water supplies?

1. social vs. political players (social view water as a right, political as a need)

2. economic vs. environmental players (economic favour hard engineering, environmental favour sustainable approaches)

Who are the players involved in issues related to water resources?

Political - international organisations, government departments, regional and local churches

economic - WB, IMF, developers of mega schemes

social - individuals, residents, land owners and farmers

environmental - conservationists, scientists and planners, NGOs e.g. WWF

what is a water transfer scheme?

- the diversion of water from one drainage basin to another (inter-basin transfer), either diverting the river itself or constructing a large canal to carry water from surplus to deficit.

positives:

-Can provide water for areas that lack water and arid areas

-Water can become a valuable resource for countries otherwise poor and undeveloped

CHINA NORTH-SOUTH

challenges in water transfers

source area:

- drop in flow up to 60%

- low flow becomes polluted = inc. impact on ecosystems sanity

- climate change + low flow = water scarcity

receiving area:

- Availability of water leads to greater use

- inc. use for development, e.g. golf

- unsustainable irrigated farming by agri-business

- Nitrate eutrophication, salination and ecosystem destruction pollution transfer

many environmental and social disadvantages surrounding scheme.

Mega Dams

- 60% of the world's major rivers have a major dam.

- Mega dams can store 16% of annual global run-off (adds to due water).

positives:

Can provide a large volume of waterCan generate HEP Reduces demand for groundwater

Negatives:

Floods land, Expensive, Countries/areas downstream suffer from a lack of water.

high evaporation rates in semi-arid areas

why are mega dams 'back in fashion'?

- China is a major dam builder (46% of worlds dams), and is doing FDI project in Africa, part of this is building lots of dams

- renewable energy

What is Desalinisation in hard-engineering?

- uses water from the Ocean, then cleans it through reverse osmosis.

- lots of TNCs are building desalination plants

- Saudi Arabia has the highest desalination capacity

Desalinisation pros and cons

Pros

- more viable than massive hard engineering schemes

- cost may decrease even further due to future carbon nanotube membranes requiring less energy

Cons

- huge ecological impact , left over water is returned from the process has double the salt concentration of sea water

- uses fossil fuels sometimes

- large carbon footprint

KEY CONCEPT - sustainability of water

- environmental sustainability protects water quality

- economic sustainability is about guaranteeing security of access to water for all, affordably. (minimise wastage, maximise efficiency of usage)

- social-cultural sustainability manages water supplies taking into account the view of all users = equitable distribution

Water conservation as a sustainable solution to managing water supply (farming)

- manages demand

in farming

- Sprinklers with automated spray technology ​or ​advanced irrigation systems are more efficient.

- recycling city waste water (grey water), e.g. North China Plains

- helping farmers makes their own decisions can cut water consumption e.g. by 30% in Uzbekistan by letting farmers control their own irrigation

- Hydroponics - growing plants using mineral nutrient solutions without soil (energy intensive)

- Legislations

- getting TNCs to manage their water usage e.g. Coca Cola

domestic water conservation

- smart meters

- rain harvesting

- ​charging​ more for water during times where there is a lack of water supply

- using​ eco-kettles

- taking a ​shower​ instead of a bath

- hosepipe and sprinkler bans

how can water be managed more sustainably through restoration?

- returning water environments back to their natural state

local scale - restoring meanders, afforestation

large scale - restoring river channels (US army corps restored 100km of the Kissimmee river)

what are cooperative agreements?

Co-operative agreements are much more varied, suggesting water is being seen more holistically - integrated water resource management (IWRM) and managing the political aspects of a basin to ensure mutual co-operation.

what are the aims of IWRM?

- freedom of corruption

- cash recovery of schemes vie effective pricing

- effective regulation of planning of use

-appropriate choices regarding water use in economic productivity

- good governance

- effective dialogue between users and providers

- forr and water security for the poor

- environmental protection of all supplies

what is IWRMs process?

ground water management:

-Aquifer storage and reuse

-Groundwater quality and quantity modelling

waterway management:

- River rehabilitation

-Sustainable water allocation

-Environmental flows

integrated urban water management:

-Water treatment technology

-Water sensitive urban design

-Water harvesting and reuse

monitoring technology

-Sensor technologies

-Real time wireless monitoring and controlling

water sharing treaties

Under the ​Helsinki rules​, international treaties must contain concepts like equitable use and shares. The criteria could be based on:

- Natural factors​ → rainfall amounts, discharge, share of drainage basin

- Social and economic needs ​→ population size, welfare of people, development

plans

- Downstream impacts​ → restructuring flow, water tables, pollution

- Dependency ​→ availability of alternative sources

- Prior use​ → the tricky question of existing historic rights and potential future use

- Efficiency​ → avoiding waste and mismanagement

Key players in water management

UN​ - UNECE (UN Economic Commission for Europe Water Convention) aims to protect and ensure the quality and sustainable use of transboundary water resources.

EU​ - Water Framework Directive agreed in Berlin 2000 - Targets to restore river, lakes, canals, coastal waters to suitable condition.

National Governments​ - e.g. the UK's environment agency which checks compliance with EU frameworks.

What is a meteorological drought?

rainfall deficit.

caused by factors such as lower precipitation, high temperatures, strong winds, increased solar radiation and reduced snow cover.

results in a loss of soil moisture, irrigation supply drops and a reduction in water available for consumption.

what is Hydrological drought?

stream flow or groundwater deficit.

caused by a decrease in inputs of precipitation and continued high rates of evaporation.

results in reduced storage in lakes and reservoirs, salinisation and poorer water quality.

what is Agricultural drought?

soil moisture deficit

Rainfall deficiency from meteorological droughts causes a deficiency of soil moisture and soil water availability

results in poor crop yields from rainfed crops, failing irrigation systems. Government aid may be required.

what is a socio-economic drought (Aka famine drought)?

a humanitarian crisis in which widespread failure in agriculture systems lead to food shortages and famines with severe social, economic and environmental impacts.

what human causes increase drought?

Humans increase drought risk by reducing the renewable water available per person. The human impacts are essentially modifying the hydrological cycle.

Human impacts:

- Depletion of water stores: groundwater, fossil groundwater, lakes

- Increased Demands: population growth

- Depletion of water quality: saltwater encroachment in coastal aquifers, surface water pollution.

- Increased losses: evaporation, soil moisture loss, reduced percolation to groundwater

what Physical factors can cause drought?

- Persistent high pressure, related to the jet stream

- Seasonal rain/monsoon failure: linked to ITCZ

- ENSO cycles change the disruption of pressure belts

- Long-term precipitation changes caused by global warming

- Teleconnections mean that the development of ENSO in the Pacific has global effects.

- Climatic variation can cause desertification

how can drought be measured?

- The Palmer drought severity index (PDSI), which applies to long-term drought related to atmospheric circulation

- Crop moisture index (CMI) measure of short-term drought, e.g. weekly, helps farmers monitor water availability in growing seasons

- The Palmer Hydrological Drought Index (PHDI) - the hydrological system responds slowly to drought, in reaction and recovery, so different models need to be developed for rivers, lakes, etc.

explain the global atmospheric circulation system.

- sun warms air so it rises over equator starting convection

- cools and sinks forming sub-tropical high-pressure zones = belt of hot dry conditions

- at ground level it creates trade winds across the equator

- trade winds meet ITCZ where warm air rises

- zone moves with seasons creation wet and dry seasons for the tropics

- warms air moves to subtropics to mid-latitudes meets cold polar front air

warm less dense air rises, cools, condenses = precipitation

- at high altitudes warm air cools and sinks to the poles

- creates a movement of air at ground level back in the direction of the equator

what is the ITCZ?

Inter tropical convergent zone.

- a belt of low atmospheric pressure along the equator. It moves north and south of the equator seasonally; this causes wet and dry seasons in the tropics.

- It causes wet season when it arrives and dry seasons when it leaves

What are mid-latitude blocking anticyclones?

Anticyclones are the opposite of depressions - they are an area of high atmospheric pressure where the air is sinking.

- results in stable, dry, and settled weather.

what conditions cause a normal year in ENSO?

1. Trade winds blow west over the Pacific (Peru to Australia)

2. to warmer water

3. causes convectional uplift from warmer sea surface temperatures

4. This pushes warm air westwards. East coast (Peru) - shallow position of thermocline allows wind to pull up cold water from below = upwelling creates optimal fishing conditions

5. pressure from trade winds causes 50cm sea rise in Australia compared to Peru, and 8 degrees warmer

6. the Walker loop returns air to the eastern side of the pacific

What are the conditions that cause an El Niño year?

1. trade winds blowing west weaken / die (can even reverse)

2. piled up water in west moves back to the east = 30cm sea level rise in Peru

3. region of rising air moves east with the direction of convectional uplift. upper air disturbances can distort jet stream, causing teleconnections globally

4. East Pacific Ocean becomes 6 degrees warmer as Nino overrides cold Humbolt Current (so breaks the food chain - less phytoplankton - less fish - affects penguins in Galapagos + fish market)

5. conditions are calmer across whole Pacific.

What are the conditions that cause a La Niña year?

Exaggerated normal year

1. extremely strong trade winds

2. push warm water westwards = 1m sea level rise in Indonesia compared to Phillipieans

3. low pressure from strong convectional uplift - heavy rain in Asia

4. increase in the equitorial under current and strong upwelling of cold water in Peru = high pressure = extreme drought.

what does El Niño do to drought risk?

- triggers dry conditions around the world in 2 years (mostly in SE Asia, India, East Australia, SE USA, Central America, NE Brazil)

- weakens the monsoon in India, exacerbating drought

- cooler ocean temperatures can cause anti-cyclone weather so very dry conditions from descending air.

What were the impacts of El Niño on Peru and Ethiopia?

PERU 1997/8 - sea surface temperatures rose by 5 degrees, disrupting the Humboldt Current = anchovy stocks collapsed by 70%.

ETHIOPIA 2015/6 - caused severe drought, 50% lower crop yield, left 10.2 million in need of food aid.

what are the key functions of a wetland?

- temporary water stores in the hydrological cycle (recharges aquifers, flood defence, habitat)

- chemically recycles nutrients and traps pollutants to help maintain water quality

- supports groundwater flow

- creates diverse food web habitat

What are the impacts of drought on wetlands?

- less precipitation, less interception as vegetation dies, lower groundwater stores, water table will fall, evaporation process will continue or increase as surface is less protected, transpiration will decrease, making wetlands less functional (can't filter water).

What are the human causes of reduced wetlands?

- 2.5 million square KM lost in Europe and the USA for agricultural development.

- The Jonglei Canal Project diverted White Nile discharge away from the Sudan swamp.

Define: groundwater flooding, surface water flooding and flash flooding.

1. floods due to saturated ground from heavy, prolonged rainfall. Low-lying land is vulnerable

2. Floods due to intense rainfall have insufficient time to infiltrate the soil, flow overland instead. Partially urbanised impermeable surfaces are most at risk.

3. where surface overland flow can develop rapidly causing a very short lag time - small basins, steep valleys, impermeable surfaces increase risk.

what are the four causes of meteorological flooding?

1. Flash floods

2. Prolonged rainfall from mid-latitude depressions- slower build-up to river flooding. causes most river floods in the UK as each depression brings two bands of rain, one a warm front and one a cold front.

- The first band saturates the ground, so the water table rises.

- In the second band, the only transfer is runoff. Quickly moves water to river channels, more river discharge, so the river spills its banks and floods.

3. Monsoon: a seasonal change in the direction of the prevailing winds of a world region (wet + dry seasons). Summer monsoons are from heavy rainfall and warm moist air following the ITCZ.

4. Winter snowfall - a sudden rise in air temperature in the spring causes rapid snowmelt in mountain environments. This increases surface runoff and flash floods.

what are four located examples for each of these meteorological causes?

1. Sardinia 2013 thunderstorms, killed 18 people and cost US$ 1.14 billion in damage

2. In the UK

3. summer monsoons in July 2015, Myanmar, unusually heavy monsoon rain killed 103 people

4. 2009, Red River in North Dakota, snowmelt on frozen impermeable ground and precipitation from a rainstorm.

What are the primary causes of floods?

climatological:

- rain, snowmelt, icemelt

part-climatological:

- coastal storm surges, estuarine interactions between streamflow and tidal conditions

other:

- earthquakes, landslides, dam failure

What are the secondary causes of floods?

vegetation, slope, rock type, drainage density (stream and basin size), soil depth.

What are the human causes of flooding?

1. Increasing population cover - vegetation removal for agriculture/houses. This increases runoff, and vulnerability will increase.

2. Deforestation

- less interception and evapotranspiration.

- Surface runoff will increase in volume and rate, so water can reach river channels quickly (flashier hydrograph).

- Exposed soil increases erosion as surface run-off will transport more sediment into rivers. (Deforestation in Nepal and Tibet impacted Ganges River)

3. Urbanisation - expansion of impermeable surfaces increase rate of surface runoff into rivers by the drainage system.

4. Floodplain drainage - reduces the natural storage capacity of the floodplain, especially where wetlands are lost. The land will shrink as it dries out, becoming lower and more susceptible to flooding.

Why is urbanisation a key factor of flood risk?

- creation of impermeable surfaces

- sped up water drainage by artificial conduits

- impending channel flow by building alongside rivers

- channelisation causes flooding downstream

- changing land use (normally agriculture related)

explain flood risk and return periods.

Flooding is a hazard, so has frequency and magnitude.

flood return period - estimate of the likelihood of a certain flood size or type recurring

Name 6 socio-economic impacts/examples of flooding.

- LICs face post-flood morbidity due to water-borne disease

- 90% of all flood deaths and 50% of economic damage occur in Asia (bad as main income is tourism)

- Flood depth in LICs has a large impact, as many are not taught how to swim

- Floods between 1990-2010 affected 3 billion

- HICs face psychological stress

- Where farming is subsistence, a direct loss to food supplies can induce famine; in HIC there can be high food prices e.g. Australia Big Dry 2006

environmental impacts of flooding

- Recharged groundwater stores, increase connectivity between aquatic habitats, move nutrients.

- Soil replenishment

In environments degraded by human activity:

- oversupplies of sediments and nutrients, eutrophication (excessive nutrients in the water body causes dense plant life growth + death of animals from lack of oxygen)

- pollution from nitrates, etc can poison soil wildlife

NILE - farmers agricultural practices rely on inundation annually as it provides nutrients. Aswan Dam stops floods, negative impact.

How will climate change affect water levels?

- Global inc. of 1.5 degrees is likely in two decades.

Extreme rainfall increases by 7% for every 1-degree increase in global heating

When the atmosphere warms up, it can hold and transport more moisture = large-scale acceleration of the hydrological cycle.

"Climate change will make wet and dry regimes more extreme"

- Changes to the world's rainfall patterns

2023 was Earth's hottest year on record, and 77 countries experienced the highest average annual temperature in at least 45 years:

- exacerbate drought in the Horn of Africa and around the Mediterranean.

- Wildfires in Canada and drought in the Amazon rainforest caused severe drought in 2023.

- cyclones brought extreme rainfall to Myanar, etc

Modelling climate change trends is complex, why?

climate dynamics - everything interacts with each other and little is understood.

teleconnections - hard to distinguish between oscillations (ENSO) and climate warming.

Global records are incomplete - hard to establish reliable trends.

What are the changes to the precipitation inputs by climate change (5 things) ?

- The mode of precipitation may become more important than the mean

- widespread increase in intense precipitation occurred, yet overall months remained steady or decreased

- areas of precipitation increase in the tropics and high latitudes.

- increased drought and heat waves in S Europe and S Africa.

- more precipitation now falls as rain instead of snow in N areas.

What are the changes to evaporation and evapotranspiration by climate change?

increasing in large areas, e.g. Asia and N America- increased cloud cover from increased rainfall may prove against this.

transpirations linked to any vegetation changes - linked to soil moisture and precipitation.

How is soil moisture altered by climate change?

ambiguous - soil moisture is related to too many factors, likely increases with increased precipitation.

How does climate change influence run-off and stream flow?

A 1-degree rise in temp could increase global runoff by 40%.

An accelerated cycle with more intense rainfall will increase run-off rates and reduce infiltration.

how does climate change influence reservoir, lake and wetland storage?

regional changes in lakes and reservoirs is linked to regional changes in climate change, e.g. Lake Chad

Wetlands are affected by decreased rainfall and increased temperatures.

how does climate change influence permarost?

Increased air and ocean temps is causing permafrost degradation in N areas.

impacts groundwater and releases methane in thaw lakes.

how does climate change influence snow and ice?

Dec. in the length of snow cover season, especially in the N. Spring melt occurs earlier, may accelerate.

global retreat in glaciers since 'little ice age'. due to inc temp and changed precipitation.

how does climate change influence Oceans?

Measuring sea surface temp has lagged behind land measurements.

in areas of ocean warming, evaporation will occur.

what are the negative impacts of climate change in the future on the UK by 2050?

- Under current policies, the total cost of climate change damages to the UK is projected to increase from 1.1% of GDP at present to 3.3% by 2050 and 7.4% by 2100.

- Strong global mitigation action could reduce the impacts of climate change damages to the UK from 7.4% to 2.4% of GDP by 2100.

- Foreign trade will cause a 1.1% fall in UK GDP as other countries experience losses from climate change.

- Agriculture is one of the UK sectors expected to be most impacted by climate change. The reduction of arable land as regions become drier will halve its total contribution to UK GDP by 2100.

what are future floods and droughts uncertain?

- multiple causes of climate change

- insufficient understanding of teleconnections within earths systems

- lack of availability of long-term big data

Future floods from climate change?

The flood figures show no clear evidence of trends in increasing magnitude or frequency globally.

Future drought trends from climate change?

- influence on precipitation, temperature and evapotranspiration = occurrence and severity of droughts.

Droughts became more widespread, intense and consistent in the last 30 years.

hard to tell the difference between climate change and human influences... SAHEL CASE STUDY.

- research studies inconclusive

- drought change determined mostly by sea surface temp

- ENSO

Short-term climate change can impact the water supply.

name 5 climate change hot spots.

1. Murcia, Spain (1.4 degree temp inc, globally we only had 1 degree.)

2. Dhaka, Bangladesh (inc. coastal flooding caused environmental refugees)

3. Mphampha, Malawi (food deficit from flash floods and long term drought, extreme temps)

4. Svalbard, Norway (climate warming of artic = widespread avalanches and permafrost melts)

5. Manaus Brazil (drying of Amazon rainforest form inc. temps and dec. humidity)

how does decision making affect water management?

- Decision-making affects water management by determining how water resources are allocated and used.

- Governments, companies and communities make decisions based on physical factors such as climate and human factors such as population growth.

- These choices influence water security, availability and access.

- They also involve trade-offs between economic development, social equity and environmental sustainability.

What is the systems approach to understanding the hydrological cycle?

Systems approaches study hydrological phenomena by looking at the balance of outputs and inputs, and how water is moved between flows.

Three concepts in how the water cycle operates?

1. stores - reservoirs where water is held, e.g. ocean holds 97.5% of our water

2. fluxes - the rate of flow between the stores

3. processes - the physical mechanisms that drive the fluxes of water between the stores

What is a closed system, and why is the hydrological cycle one?

When there is a transfer of energy but not matter between systems and not the surroundings.

All the water within the system is continually circulated through the stores and there is not water that is added or destroyed, this means the system doesn't change. This global circulation of water is driven by solar energy, heated by the sun.

Name and describe the four water stores on earth.

1. oceans - 97% of water stored in liquid form (and ice), stays here 3,600 years.

2. cryosphere (areas of earth where water is frozen) - 1.9%, stays here up to 15,000 years.

3. On land, there are two types of water:

blue water - the visible part of the hydrological cycle, e.g. rivers. stays here from 2 weeks to 50 years.

green water - water stored in the soil and vegetation. stays here up to 10,000 years in deep groundwater.

4. atmosphere - 0.001%, water only stays here for 10 days

What are residence times?

The average estimated time a water molecule will spend in a store. Impacts the turnover in the water cycle.

Stores with a slower turnover time are more easily polluted.

key terms: define precipitation, evaporation, fossil water, transpiration and groundwater flow:

precipitation - movement of water in any form from the atmosphere to the ground

evaporation - change of state of water from liquid to gas

fossil water - ancient deep groundwater from pluvial (wetter) periods

transpiration - diffusion of water from vegetation into the atmosphere, liquid to gas

groundwater flow - slow transfer of percolated water underground through pervious and porous rocks.