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GCSE GEOGRAPHY REVISION handbook UNIT 1 EDEXCEL B Unit 1: Dynamic Planet Revision Guide. Unit 1 is worth 25% of your final GSCE Geography Grade. You will have to answer a range of questions (maximum 6 mark answers) on 6 topics (see below). Use the information below help you revise. Ensure you start your revision early to stop any panic nearer the time. In Section B (see grid above), you will ONLY answer the questions on Coastal Change and in Section C ONLY Oceans on the Edge. 2 Unit 1: Dynamic Planet Battle For the Biosphere: What you need to know: Check list What 3 things make up the biosphere? Lithosphere (land), hydrosphere(water) and atmosphere (air). What is a biome.? Be able to describe the location of tropical rainforests, deserts, polar and savannah grassland and why they are found there. What factors affect the distribution of biomes? Latitude, altitude, continentality (is it close to a coast or inland), geology. What is a ‘service’ that humans get from the biosphere and be able to give examples. What is a ‘good’ that humans get from the biosphere and be able to give examples. How do humans degrade the biosphere? How can the biosphere be conserved? Biosphere conservation, CITES, National Parks, World Heritage Sites and sustainable management. Know briefly how each works. Case study – Korup National Park. Climate and Change What you need to know: What is climate change? What will graphs show about climate in the past? What are the natural causes of climate change? Orbital changes, solar output, volcanic activity. How can you find out what the climate was like in the past? (Apart from written records) Ice cores, tree ring dating, paintings, diaries etc… Natural climate change has affected people and ecosystems, give examples. E.g. Greenland’s Vikings, farming etc… Give a couple of examples of things that are extinct due to natural climate change. What is the greenhouse effect and what are the GHGs? CO2, methane, 3 Check list Unit 1: Dynamic Planet nitrous oxide and water vapour. What has happened to the climate since the 19th Century and why? Give some examples / evidence of climate change? E.g. drought etc… Summarise your Bangladesh case study. What is the ‘tipping point’? How can we reduce climate change on a local, regional, national and global scale? Is global warming all bad? What is the ‘Stern Review’? Why do some people not believe in global warming? Restless Earth: What you need to know: Check list Earth structure – inner core, outer core, mantle and crust. The two types of crust and which is heavier – oceanic and continental. The four plate boundaries; conservative, constructive, destructive and collision. Convection currents – what they are, where they occur and how they cause plates to move. The two types of volcanoes and examples of each. The two types of earthquakes and examples. The impact of volcanoes and earthquakes. How to prepare for earthquakes and volcanoes. Water World: What you need to know: What happens in the hydrological cycle and understand that it links the atmosphere, lithosphere and biosphere. Changes to the hydrological cycle can affect both human and ecosystem health. Unreliable water supply and the impact on humans case study; Australia or Sahel. Impact of climate change on the hydrological cycle and ecosystems. 4 Check list Unit 1: Dynamic Planet Mini case-studies; Australia, Maldives, Arctic, Ethiopia, Africa, Caribbean and Bangladesh. Know examples of what can threaten a healthy hydrological cycle. E.g. pollution, farming, industry; mining, sewage, transport etc… Know example of how human interference can disrupt water supply e.g. deforestation, over-abstraction of groundwater and reservoir and dam construction. Know the costs (negatives) and benefits of a large scale water management scheme; The Colorado River. Understand what intermediate technology solutions are and an example; Afridev in Tanzania. Coastal Change and Conflict: What you need to know: How and why do coasts vary – what are they used for? What is geology and how does it affect the coast? (resistant/non-resistant rock; E Yorkshire vs Land’s End; discordant/concordant) Physical processes along the coast (E T D); inc. wave types Landforms of erosion (Headlands and Bays, Stacks and stumps and wavecut-notch). Transportation along the coast (long shore drift) Landforms of deposition (Spit, Tombolo and Bar) Coastal defences – what are they? Pro’s & con’s and what do: hard and soft engineering mean and ‘traditional’ and ‘more modern’ approaches mean. 5 Check list Unit 1: Dynamic Planet Oceans on the Edge: What you need to know: Know the global pattern of human use of a marine ecosystem; mangroves swamps. Understand the global pattern of threats to this ecosystem due to human activities. Know the processes that disrupt marine food webs e.g. over-fishing, and cause nutrient cycles to be disrupted e.g. eutrophification and siltation. Understand the role of climate change in adding additional stress to threatened marine ecosystems. E.g. bleaching, warming oceans or sea level rise. Using a local-scale, named case study to investigate the growing localised pressures on a named marine ecosystem. Understand that different local groups may have different opinions on how to manage this area and this can cause conflict. Assess two local case studies of marine management. Assess the global actions to maintain ocean health. 6 Check list Unit 1: Dynamic Planet UNIT 1 : DYNAMIC PLANET Atmosphere Hydrosphere Biosphere Geosphere The layers of gases/air around us. The layer of water. The very thin layer of living things on the crust. The rocks of the crust and deeper towards the core. How are we damaging each of the spheres? Atmosphere releasing CO2 into. Hydrosphere using too much water in some areas Biosphere deforestation (chopping down the trees) animals extinct. Geosphere using up fossil fuels The layers of the earth… The lithosphere (which is solid) is split into tectonic plates. These move slowly (2-5cm/yr) on top of a layer called the asthenosphere (which is like porridge) CONTINENTAL CRUST = land, low density, thick. OCEANIC CRUST = under the oceans, thin, dense. Meteorites give us a clue as to what the core is like. How do we know that the inside of the earth is hot? lava from volcanoes hot springs, geysers Geothermal heat… 7 Unit 1: Dynamic Planet Heat from the inside of the earth. Produced by the radioactive decay of uranium etc in the core and mantle. As heat rises from the core it creates convection currents in the liquid outer core and mantle. These convection currents move the tectonic plates on top of them. PLUMES = where heat moves to the surface e.g. hotspots like Hawaii. The magnetosphere…. The earth is surrounded by an invisible magnetic field –made by the outer core – protects the earth from harmful radiation from space/the sun. Pangea… The continents were once all joined together – Pangea. How do we know this? Identical fossils and rocks have been found in western Africa and Eastern South America for example. Today the lithosphere is split into 15 tectonic plates. Where 2 plates meet together = plate boundary. Constructive plate boundary… Where two oceanic plates are moving apart from each other. New oceanic crust is forming constantly in the gap created. The magma is injected between the two plates. As it cools it forms new oceanic crust. The magma is runny. Shallow sided volcanoes form. HAZARDS: Convection currents from the Small earthquakes are formed by friction as the plates tear apart. mantle bring magma towards Volcanoes that are not very explosive/dangerous. the surface. Magma is forced Examples are Iceland – the Mid Atlantic Ridge between the plates, cools and forms new oceanic crust. Destructive plate boundary… Where an oceanic plate meets a continental plate. They are moving towards each other. The denser oceanic plate is subducted beneath the less dense continental plate. HAZARDS: very destructive earthquakes tsunami very explosive, destructive volcanoes which cool to 8 Unit 1: Dynamic Planet be steep sided. Examples are Andes mountains, Peru, Chile. Conservative plate boundary… Formed where two plates are sliding past each other. HAZARDS: destructive earthquakes small earth tremors daily. no volcanoes Example is San Andreas Fault, California Collision Zone A type of destructive boundary where two continental plates move towards each other. As they meet they push upwards forming mountain ranges e.g. Himalayas. HAZARDS: destructive earthquakes landslides volcanoes are rare Volcanic Explosivity Index (VEI) Measures the destructive power of a volcano on a scale from 1 to 8. Volcanic Hazards: Pyroclastic flows – deadly clouds of hot ash and gas. Landslides Lahars – volcanic mudslides Lava flows Ash builds up on the roofs of houses buildings collapse. Acid rain is created. NAMED EXAMPLE: Sakurajima, Japan Stratovolcano/ composite volcano (steep sided) Destructive plate boundary Can erupt 200 times a year. ADVANTAGES OF THE VOLCANO 40% of the land is fertile, volcanic 9 DISADVANTAGES OF THE VOLCANO 7000 people live at the base (are Unit 1: Dynamic Planet soil can grow rice and tea. vulnerable). Hot springs are a tourist There are lots of urban areas attraction. around the base. Sheltered bay is good for the The volcano hurls bombs of lava. fishing industry. Pyroclastic flows and ash erupting. Managing the threat: Japan is a developed country so has money….. MONITORING AND PREDICTION Aircraft monitor the amount of gas being given off. Tiltmeter detects swelling of magma in the rocks. Boreholes measure the temperature of the water. Hotsprings are monitored Seismometers monitor earthquake activity. PROTECTION Concrete shelters protect people from bombs/ash. Concrete lahar channels divert dangerous mudflows. EVACUATION Evacuation routes clearly sign posted. Evacuation drills. Why are people in developing countries at greater risk from tectonic hazards than people in developed countries? More live in risky conditions – no where else for them to live. Can’t afford safe, well built houses they collapse easily Don’t have insurance Governments don’t have the money to provide aid. Poor communications – no warning or evacuation. NAMED EXAMPLE: MOUNT NYIRAGONGO, DEMOCRATIC REPUBLIC OF CONGO, AFRICA African rift valley Constructive boundary 2002 hot and runny lava poured out. A river of lava 1000m wide flowed 20km into the city of Goma. 14 villages destroyed 100 died – due to poisonous gas and trapped in the lava flow. 12 500 homes destroyed 10 Was predicted – 400 000 were evacuated Refugees created (people forced to move due to natural hazards or war) Unit 1: Dynamic Planet AID AND RELIEF EFFORT ( help given by organisations/countries to help those facing an emergency). United Nations sent 260 tonnes of food. UK TV appeal Governments around the world gave $35 million Emergency measles vaccinations by the World Health Organisation. most fled with nothing it was months before they could start rebuilding. EARTHQUAKES can’t be predicted. Underground plates try to push past each other– builds up pressure – suddenly released along faults (cracks in the crust). Energy is sent out in all directions. Magnitude = power of the earthquake Seismometer measures the power on the richter scale NAMED EXAMPLE:Niigata, 2007 AND Kobe 1995, both japan, how different? Both earthquakes were the same magnitude but… Niigata, 2007, Japan Kobe, 1995, Japan City of 90 000 – low population City of 1.1 million ( high population density density) 11 died 5000 died 1000 injured 26 000 injured Epicentre was offshore (out to sea) Soft ground made the shaking so less shaking of the land. worse 6pm. People were alert and 6am so people asleep and confused. remembered their drills. Long term planning… There is a 70% chance of a huge earthquake hitting Tokyo. No way to predict it so…. Earthquake drills Emergency services practice rescuing people People keep emergency kits at home – water, torch, radio, food. BUILDINGS… Strong, double glazed windows – stop the glass from shattering. Shock absorbers Strong steel frame Cross bracing Very deep foundation Earthquakes in the developing world… 11 Very high death tolls Unit 1: Dynamic Planet NAMED EXAMPLE: SICHUAN, Central china 2008 8.0 on the Richter scale Collision zone where the Indian and Eurasian plates are colliding. No warning PRIMARY EFFECTS (Caused instantly by the earthquake) 70 000 died 400 000 injured 5 million made homeless $75 billion damage SECONDARY EFFECTS (in the days and weeks following the earthquake) Lots of aftershocks buildings collapse LOCAL RESPONSES: Prime minister flew in 50 000 soldiers helped dig for survivors Helicopters used to reach the isolated $1.5 billion aid from the Chinese people INTERNATIONAL RESPONSES: Some countries sent money – UK $2 million Finland sent 8000 tents Indonesia sent medicines Rescue teams from Russia and Hong Kong 12 Unit 1: Dynamic Planet UNIT 2: CLIMATE AND CHANGE WEATHER = short term, day to day changes in the atmosphere. CLIMATE = the average weather conditions over 30 years. How do we know climate was different in the past? Fossils of animals and plants that no longer live in the UK. Landforms left by glaciers Samples from ice sheets in Antarctica. Ice sheets are made up of layers of ice, a layer for each year. Trapped in the ice sheets are air bubbles. Climatologists study the CO2 levels to reconstruct past climates. INTERGLACIALS = warm periods GLACIALS = cold periods ice ages ice sheets 400-3000m thick extended across the northern hemisphere. How do we know climate has changed in the more recent past? Old photos, paintings Diaries Newspapers Recorded dates of blossom and migration of birds. Theories used to explain why climate has changed in the past (Natural events).... 1. 2. 3. 13 ERUPTION THEORY – very large and explosive volcanic eruptions change earth’s climate. Ash and gas spread around the stratosphere and stop sunlight reaching the earth’s surface cools the earth. Example is Mt Pinatubo, 1991, Philippines – reduced global sunlight by 10% and cooled the earth 0.5 degrees for a year. SUNSPOT THEORY – black areas on the sun’s surface. Some times there are more then they disappear. Spots mean greater activity and more solar energy being sent towards the earth warmer. ORBITAL THEORY/MILANKOVITH CYCLES – Changes in the way the earth orbits the sun from circular to ellipse alters the amount of sunlight the earth receives. Unit 1: Dynamic Planet NAMED EXAMPLE: the little ice age Greenland Vikings ran out of food and died as temperatures fell. In England there were ‘frost fairs’ on the river Thames when it froze. Crops failed ‘Great famine’ Farmers died of hunger Glaciers in the Alps grew and destroyed villages They had to change their crops from wheat to potatoes Ecosystems – where plants and animals interact with each other and their environment in order to survive. Can be small e.g. pond or large e.g. Tropical Rainforest. How were ecosystems affected by climate change in the past? The dinosaur extinction was possibly caused by a massive asteroid hitting Mexico and a huge volcano in India combining dust, ash, gas into the stratosphere blocks the sun cools the climate plants don’t grow dinosaurs have no food……..knock on effect through the food chain. Megafauna extinction – big animals like the woolly mammoth. The climate was warming so they had to find new areas to live where the climate suited them. This disrupted food chains. Humans also hunted them to extinction. How is our atmosphere being changed by human activity? Greenhouse gases (CO2 from the burning of fossil fuels, deforestation, Methane from paddy fields and cattle, Nitrous oxide from aircraft engines and fertilisers) trap heat from leaving the atmosphere and re-radiate that heat 14 Unit 1: Dynamic Planet back down to earth. The greater the concentration of greenhouse gases, the more heat is trapped and the warmer earth becomes. We need the NATURAL greenhouse effect – it makes the planet 16 degrees warmer. Without it the earth would be too cold for us to survive. The extra greenhouse gases produces by humans burning fossil fuels power stations, transport, industry, homes. Most greenhouse gases are produced by developed countries – the EU, USA, Japan. The average person in the developing world the developed world produces 1 tonne of CO2. of CO2. The average person in produces 10-25 tonnes We are worried about increasing emissions. Issues we need to think about: how can we decrease emissions in the developed world. how can we persuade developing countries e.g. China, India to slow their CO2 emissions. how do we protect vulnerable people from the impacts of climate change? GLOBAL WARMING = a warming of the earth’s temperatures caused by the ENHANCED greenhouse effect (human’s have polluted the atmosphere so it is working more strongly). Global temperatures increase. sea levels rise THERMAL EXPANSION (water droplets expand as warm) and glaciers and ice sheets melt. What evidence is there of Global Warming happening? 19 out of 20 warmest years on record since 1980. Sea ice in the Arctic shrank. 90% glaciers shrinking. Scientists disagree – are human actions the main cause of global warming OR is it mostly natural?? 15 Unit 1: Dynamic Planet Predicting future Global Warming is hard….as we don’t know: What the future population will be. If we will continue to use fossil fuels or change to cleaner fuels e.g. solar, wind power… If we will change our lifestyles recycle use public transport etc. How might the UK be affected by Global Warming? 1. Likely to be WARMER: 2. COSTS Summer drought and water shortages, especially in the south. More illnesses e.g. sunstroke, skin cancer. Roads melt, railway lines buckle. Farmers change crops to those that need less water and more sun. Extinctions of some plants and animals as it gets too hot. BENEFITS Winter heating costs and the costs of gritting the roads fall. Tourism increases – good for the economy. Fewer deaths in winter especially the elderly from the cold. More land can be farmed at higher altitudes. SEA LEVEL rise Low lying coasts could flood Greater erosion e.g. Holderness Sea defences and flood barriers would cost £millions. 3. More EXTREME WEATHER Heatwaves Floods Storms Extreme weather is hard to predict and costly. The Stern Review 2005 We should spend 2% our GDP now, reducing pollution OR the effects of global warming could decrease our GDP by 20%. ‘Spend now or pay later’. What can we do? 16 Decrease fossil fuel use. Switch to ‘green energy’ – wind, solar, tidal. Recycle more Unit 1: Dynamic Planet Use cars less and public transport more. 1997 Kyoto Protocol = international agreement to cut CO2 emissions. Some countries e.g. UK have cut emissions, others e.g. China haven’t. We need ALL countries to sign up. NAMED EXAMPLE: Egypt – the possible impacts of Global Warming A developing country Low greenhouse gas emissions – 2.6 tonnes per person per year (world average = 6.8) Produce less than 1% all green house gases. 99% of Egypt’s people live in 5% land area as so much is desert. Average rainfall = less than 10mm/yr The River Nile is an important water supply. With Global Warming… If sea levels rise 50cm, 1/3 of the city of Alexandria would be under water. 10% Nile Delta would flood 7 million people would have to leave their homes. farming would be hit. there would be less food famine. Less and more unreliable rainfall water shortages. Desertification Heatwaves illness and death. Malaria increase. Water Wars?? 86% of the Nile’s water starts it’s journey in Ethiopia. Uganda, Sudan and Ethiopia are all building huge dams for Hydro Electric Power (HEP). This could have a serious impact on the amount of water reaching Egypt. This could lead to conflict and war. Egypt has a debt of $30 billion. It may not be able to cope with the impacts of global warming. 17 Unit 1: Dynamic Planet UNIT 3: BATTLE FOR THE BIOSPHERE BIOME = WORLD SCALE ECOSYSTEM The world has 9 major biomes – determined by climate: Temperature – length of the growing season Precipitation Sunshine hours – precipitation Humidity Why does climate vary around the world? LATITUDE: At the equator the sun’s rays hit the earth at right angles, therefore concentrating the insolation and making it very hot. At the poles the rays hit at a greater angle, so the insolation is spread out over a greater area and is much less concentrated. At the equator the air is always rising = LOW pressure = clouds and rain = rainforests. At 30 degrees north and south of the equator the air is always sinking = HIGH pressure = no clouds and no rain = deserts. ALTITUDE: (height of the land) – as height increases so the climate gets increasingly cold and wet. Temperature decreases 1 degree for every 100m of height. 18 Unit 1: Dynamic Planet THE SEA: keeps places near the coast cooler in summer and warmer in winter (as water heats up and cools down more slowly than the land) this is called continentality. PREVAILING WINDS: If the most common winds come from across the land, the climate = dry. If across the sea, the climate – wet. From the poles = cold, from the equator = warm. A climate graph… The RED line graph = average temperature for each month. The BLUE bar graph = average rainfall for each month. TEMPERAURE RANGE = difference between min and max temperatures. Goods and services GOODS = things of value to us SERVICES = things that satisfy our needs BIOSPHERE GOODS Fruit, nuts Food crops Meat, fish, wood Biomass for energy Drinking water, water for farming Gene pool BIOSPHERE SERVICES Pollination for food webs Climate regulation Atmosphere gas balance (trees remove co2 and give out oxygen) Jobs Recreation – tourism Homes for humans and wildlife Biodiversity NAMED EXAMPLE: THE TROPICAL RAINFORESTS TRF indigenous people (lived their for many generations) - almost everything provided by the rainforest: Wood for cooking and building herbs for medicine food – nuts, fruit, meat, fish grow crops – shifting cultivation (sustainable process) BUT… TNC’s exploit the TRF logging for timber/paper farming – palm oil for example cattle ranches mining for oil 19 Unit 1: Dynamic Planet governments building dams for HEP roads This means… The soil is eroded and washed away floods. Wildlife loses habitats Rivers become dirty and polluted PLAYERS… Different people and organisations who use the biosphere in different ways. NAMED EXAMPLE: The Guyana Mountains Rainforest The Guyanan government is short of money and in debt. They wanted to develop the rainforest for timber and mining. Environmentalists and local people opposed this How is the biosphere being degraded by human actions? Every year the ‘red list’ of endangered animals is produced. Increasingly, habitats are being damaged and destroyed this leads to increased threat of species survival. Immediate causes = logging, overfishing, pollution Root causes = increasing populations, economic development e.g. China, India now = more money and therefore consuming more food and fuel etc. Certain species and places are particularly under threat. There are 25 ‘hotspots’ where there is greatest concentration of biodiversity (number of plants and animals). OVERHARVESTING/OVERHUNT ING/OVERFISHING e.g. Krill MINING Oil e.g. Alaska POLLUTION air/water 20 DEFORESTATION: Logging increased flooding and increased soil erosion e.g. Amazon Rainforest. Threats to the biosphere… INTRODUCING ALIEN SPECIES CHANGING LANDUSE to farmland/urban – changes the ecosystem TOURISM AND RECREATION disturbs wildlife. Unit 1: Dynamic Planet How have ecosystems changed over time? MASS EXTINCTION = extinction of a large number of species in a short time. Are we heading towards another mass extinction? We are threatening the ability of the biosphere to provide goods and services due to: Population growth Using more food, oil, water, minerals Human induced change (global warming) Impacts of climate change on the biosphere: Habitats broken up Habitats change due to increasing temperatures, changing rainfall, rising sea levels Extreme weather = more common Oceans = more acidic as more freshwater is added. Kills coral reefs. Increased pests and diseases. Species face extinction Krill numbers falling Glaciers melting Emperor penguins decreased 50% How can we conserve the biosphere? Should we save the hotspots or a representation of all of the biomes? Should we restore devastated areas? Should we conserve high profile animals or keystone species (have a large effect on other living things e.g. bees) GLOBAL ACTIONS… (countries working together) RAMSAR conserving wetlands CITES stop ivory trade/crocodile skins NATIONAL ACTIONS… (a particular country) National Parks England and Wales – protected areas e.g. The Peak District Community Forests – new areas of trees near cities Paying farmers to replace hedgerows LOCAL ACTIONS… (local area) Biodversity action plans e.g Havering Wildlife Trust, Bedfords Park. SUSTAINABLE MANAGEMENT – meeting the needs of the present without compromising the needs of future generations. Tropical Rainforests – make sure it isn’t used faster than it is renewed. Ways to do this… Zoning 21 Unit 1: Dynamic Planet Educating local people Ecotourism Protected areas Only cut large trees NAMED EXAMPLE: Klum, Cameroon Republic: Sustainable Forest Reserve an area of selective logging tree nurseries to replace trees cut down (afforestation) ecotourism protected areas crops grown beneath the trees instead of cutting them down. UNIT 4: WATER WORLD THE HYDROLOGICAL CYCLE The hydrological cycle is a CLOSED SYSTEM – A finite amount of water going round and round. None is added or lost. STORES: rocks (can be stored for 100’s yrs), soil, lakes, oceans (97% water stored BUT too salty to use) glaciers. The soil, lakes and rocks hold relatively small amounts of fresh water – but are in high demand as sources of water.. TRANSFERS/FLOWS: Surface runoff, throughflow, groundwater flow, infiltration, precipitation. Intercepts precipitation 22 ½ is evapotranspiration without ever reaching the ground = GREEN WATER Unit 1: Dynamic Planet Drips from leaves and infiltrates the soil Water Crisis Demand increases as population increases. Increased demand from agriculture – irrigating their crops uses huge amounts of water. Supplies are increasingly unpredictable Possibility of water wars – Middle East – fighting over water. Economic development – China, India – increased demand for water Rising living standards = use more water e.g. showers, washing machines etc. Population growth Tourism – hotels, golf courses = huge amounts of water Agricultural demand urbanisation Decline in water availability and quality Energy – reservoir storage for HEP = through evaporatio Industrial developmen Climate change = rain less reliable in some places Only ½ freshwater runoff (BLUE WATER) is used. Most is inaccessible. WATER STRESS = when demand is greater than supply or when it is not of good enough quality to use. Turkmenistan and Uzbekistan are the most water stressed countries in the world they use huge quantities for irrigating cotton crops. SW USA, Central Asia = PHYSICAL WATER SCARCITY – Demand > availability Sub Saharan Africa = ECONOMIC WATER SCARCITY – supply available but people can’t afford to exploit them. Lack of money to build storage facilities or distribute water. NAMED EXAMPLE: SAHEL 23 Belt of semi-arid land south of the Sahara, Africa. Unit 1: Dynamic Planet Rains usually 1 or 2 months a year. Total 250-450mm/yr. Since 1970 rainfall has been below average. Some years 25% less than average. Sometimes rainfall is so heavy when it does fall that most is lost as surface runoff leading to flooding. Other years there is no rain at all rivers dry up water table falls farmers crops fail animals die desertification decreased food supplies famine. Global warming means… Less rain for some areas Increased rate of glacier melt More extreme weather events floods and storms and droughts. Richer countries e.g. Kuwait, Saudi Arabia (profit from oil) can buy their way out of trouble e.g. desalination turning sea water into fresh water (very expensive). Developing countries rely on rainfall for their crops + unstable food insecurity and famine. Water quality… People can suffer economic water stress if water isn’t safe. Pollution can be: domestic, industrial, agricultural, transport related. Salt runoff from roads sewage Disposal of hazardous waste Cattle waste (slurry) Fertilisers washed in Sources of water pollution Crop spraying Runoff from building sites Industrial discharge Chemicals applied to golf courses Developing countries… The highest levels of pollution are found in rapidly developing countries like India and China – they put economic growth before environmental protection. Rapidly growing cities means slums streams = badly polluted as no sewage systems in place. Chemicals added to crops = runoff…. Developed countries… E.g. UK, Japan – have taken big steps to control pollution. 24 Unit 1: Dynamic Planet Tertiary and quaternary industries cause less pollution than primary and secondary. NAMED EXAMPLE: – Japan – ‘60’s = heavily polluted rivers and lakes. 70’s government introduced standards to improve water quality. Now much better. Impacts of pollution… Diseases e.g. cholera Eutrophication – fertilisers make algae grow really fast – takes all O2 out of water – all living things in river/lake die. Cancer (Erin Brokovitch) Interfering in the hydrological cycle… We use water for: farming, drinking, washing, industry, habitats for plants and animals, power generation (HEP), waste disposal. How people intervene in the water cycle: 1. CLOUD SEEDING: making it rain 2. DEFORESTATION: Decreased interception increased flooding 3. URBANISATION: Increased impermeable surfaces 4. OVERABSTRACTION: taking too much water from rivers and lakes 5. BUILDING DAMS AND RESERVOIRS 6. GLOBAL WARMING: melting glaciers OVERABSTRACTION: Too much water is being taken from the river/lake/water source. NAMED EXAMPLE: Thames Valley, S. Eng. Dramatic decrease in river flow Tributaries dried up Ecosystem damaged Droughts and increased demand from more homes increased use of groundwater supplies falling water table so the store of water is not used sustainably. most water companies now have strict policies CAMS for managing water levels. RESERVOIR BUILDING: Adds a new store to the hydrological cycle. But….brings PROBLEMS: loss of land – drowns villages, farmland disease – stagnant water mosquitoes vegetation drowned releases methane = greenhouse gas BENEFITS: Water supply 25 Unit 1: Dynamic Planet Recreation – fishing, sailing, walking, wildlife DEFORESTATION Fewer trees = less evapotranspiration. Less green water recycled = less rain. Soil left exposed to the sun and rain Less nutrients in the soil Raindrops wash out the finer soil, leaving coarse, heavy surface. Less interception greater flood risk Solutions to the water crisis… If we use water faster than it can be replenished this is not sustainable Large scale water management projects: Big dams BENEFITS Increased water supply Recreational use HEP – Industry Habitat for water birds Fishing DISADVANTAGES loss of farmland/villages less navigation people have to be relocated disease – stagnant water loss of cultural sites interferes with fish migration NAMED EXAMPLE: china: south to north water diversion project To transfer water from the south to the dry north. Complete 2050 Loss of ancient sites, displaced people NAMED EXAMPLE: three gorges dam To provide HEP and prevent flooding Impacted biodiversity 1.4 million people had to be relocated Small scale solutions… NGO’s (Non Governmental Organisations) e.g. WaterAid develop small scale solutions. APPROPRIATE/INTERMEDIATE SOLUTIONS: Schemes that meet the needs of local people and the environment in which they live. Within their technical ability – they can operate and maintain the scheme themselves. They can continue to run it when the NGO has left e.g RAINWATER HARVESTING – using guttering to collect rainwater and divert it into a tank. TUBE WELLS – to pump up water. LOW COST PIT/COMPOSTING TOILETS. 26 Unit 1: Dynamic Planet NAMED EXAMPLE: DHAKA, BANGLADESH Old Zhimkhana – slum on disused railway station. No safe water or toilets. WaterAid constructed 6 tube wells and 2 new sanitation blocks people are no longer continually ill they can run facilities themselves moving out of poverty In the past women had to walk long distances to get water. Now they have safe water for drinking, cooking, washing and personal hygiene. Problems of small scale schemes… A huge number of people suffer from HIV/AIDS too ill to operate. In general, Intermediate technology is more sustainable than large scale schemes. 27 Unit 1: Dynamic Planet Topic 6 River Processes and Pressures Don’t forget the role of rivers in the hydrological cycle; Hydrology is the study of water. The hydrological cycle is the movement of water between the atmosphere, land and oceans. Precipitation - all forms of rainfall, snow, frost, hail and dew. Interception - precipitation that is collected and stored by vegetation. Infiltration - water that seeps into the ground. Transpiration - water loss from vegetation to the atmosphere. Evapotranspiration - the combined losses of transpiration and evaporation. Water storage - the temporary storage of water in lakes, dams, reservoirs and rivers. The main processes of a river at work Erosion is the wearing away of land, there are 4 main types of erosion: Diagram Abrasion (or corasion) Bed Attrition Corrosion (or solution) Hydraulic Pressure (or 28 Channel Type of Erosion Explanation This is when the river throws material against the channel This is caused when rocks and pebbles bump into each other and break into smaller pieces This is where salts and other acids in the salt water slowly dissolve away the coast This is when air gets trapped in a crack in the river bank. The air gets Unit 1: Dynamic Planet hydraulic action) compressed and expands, opening the crack Rivers can erode: Vertically – erodes material from the river bed Laterally – erodes material from the river banks More acidic water increases rates of solution Ph Soft rocks erode faster than harder rock Human Activity Geology Deforestation, dams and bridges interfere with the natural flow Factors Affecting Erosion The steeper the gradient the greater the erosion potential Gradient Load The heavier and sharper the load the greater the erosion potential Velocity The faster the river flow, the greater the erosion potential The material that the river carries is called its load. The load can be large boulders, rock, pebbles or tiny grains of silt. How much load a river can carry depends on the energy or power the river has. Transportation is how the load is carried within the river Traction – where large rocks and boulders are rolled along the river bed. Saltation – where smaller stones are bounced along the river bed in a leap frogging motion Suspension – where very small grains of sand or silt are carried along with the water 29 Unit 1: Dynamic Planet Solution – where some material is dissolved (like sugar in a cup of tea) and is carried downstream. Deposition occurs when the river’s load is too big to carry and it can create some interesting and unique features. The most significant process within a river valley or drainage basin is erosion by the river itself. Although the sub-aerial process of weathering which operates on the valley sides is important too! Weathering is the breakdown of rocks in situ. This means it happens where the rock is. Rocks are weakened by being chemically attacked and mechanically broken down. The main ways that rock is weathered are: Freeze-Thaw Weathering Chemical Weathering Most rain contains a small amount of acid. When it falls on rock it slowly eats into it. It makes the rock rot and crumble away Onion-Skin Weathering The sun heats the rock and its outer layer expands. When it cools down at night it shrinks again. After this happens many times, the outside of the rock peels off like an onion. Biological Weathering A seed falls into a crack in a rock and it may start to grow. As the roots grow they force the crack to get wider. The rock breaks into pieces. Mass movements can occur once the rock on the valley sides is broken up. The fragments of rock can move fairly rapidly in the form of a landslide, or slowly, most common is soil creep. Landslides (and mudflows) are relatively rapid movement of material. They are less common in the UK, but can occur along the coast and railway cuttings Soil creep is a slow process where slope material moves at about 2cm per year. Over decades it can have many effects such as, bent trees, leaning telegraph poles and/or walls. The shape of a river valley is affected by 3 things: 30 Unit 1: Dynamic Planet The speed of weathering The speed of mass movements How quickly the river can move material brought by mass movements The Long Profile of a River A river has a very distinct profile that changes from source to mouth. There are distinct sections of a rivers’ profile and each section has features and processes associated with it. The long profile is a section along a river from its source to its mouth. The upper section is normally steep, whereas the lower section is usually flatter. The river is able to erode through its flood plain down to the new lower sea level. The UPPER course of a river is V-shaped. It has a steep gradient and the valley is relatively narrow. The river is often quite shallow and relatively fast flowing. There is lots of friction with the large boulders found on its bed and the river uses most of its energy to overcome friction. One of the most impressive features in this section is a waterfall. Waterfall Formation Waterfalls frequently occur on horizontally bedded rocks. The soft rock is undercut by hydraulic action and abrasion. The weight of the water and the lack of support cause the waterfall to collapse and retreat. Over thousands of years 31 Unit 1: Dynamic Planet the waterfall may retreat enough to form a gorge of recession. Gorges form through the retreat of waterfalls over thousands of years. In the MIDDLE Course the slopes are gentle. Lateral (sideways) erosion is beginning to form a flood plain. There is also a larger volume of water in the river due to tributaries. One of the most impressive features in this section of the river is a meander. Meanders are caused by helical flow; this means water on the outside of the bend moves faster and therefore erodes, while the slower moving water is on the inside of the bend. This means material is deposited to form a point bar (a little beach in the inside bend). Meander Formation Continued erosion at the neck of the meander can create an Ox-bow Lake. 32 Unit 1: Dynamic Planet In the LOWER Course, the Valley sides are very gentle, almost flat. Typical processes include erosion (on the outer banks, especially during times of flood), transport, and deposition (especially on the inner bends and on the floodplain). Typical features include levees, ox-bow lakes, floodplains and terraces. Intense use is made of lower courses of rivers on account of their gentle gradient, large supply of water, fertile valleys, and terraces which are free from flooding. A floodplain is an area of land at the side of a river that fills up when the river floods. Floodplains are often flat and fertile and may be used for farming. However, floodplains normally flood each year, so they may be used for animals rather than crops. Floodplains often contain levees and sometimes they have ox-bow lakes. A levee is a raised bank on the edge of a river, formed by deposition of material each year when the river floods. When the river floods its speed is reduced. As its speed is reduced it has to deposit some of its load. It drops the coarser, heavier material first and the finer, lighter material last. Levees are built up of coarse material, while the flood plain consists of fine silt and clay. Delta For deltas to be formed a river needs to: 33 Unit 1: Dynamic Planet Carry a large volume of sediment Enter a still body of water The coarser material is deposited first, and the finest material last, and furthest away. A river regime is the annual variation in the flow of a river. In Britain, river flows are higher in winter because: higher rainfall lower temperatures and hence lower evapotranspiration less interception by deciduous vegetation A storm hydrograph (or flood hydrograph) shows how a river changes in response to a storm or period of heavy rainfall. The rising limb shows how quickly the flood waters begin to rise. The peak flow is the maximum discharge of the river. The time lag is the time between the height of the storm and the maximum flow in the river. The recessional limb is the speed with which the water level in the river declines after the peak. Baseflow is the normal level of the river, which is fed by groundwater. Climate Human Activity Soils Factors Affecting Hydrographs Drainage Density Slope Angle Vegetation Infiltration Capacity Link your knowledge of the hydrological cycle to storm/flood hydrographs. Rock Type Urban hydrographs are different to rural ones. Use the language of the hydrological cycle. They have: A shorter time lag A steeper rising limb A higher peak flow A steeper recessional limb 34 This is because there are more impermeable surfaces in urban areas as well as more drainage channels Named Example: MEDC FLOOD: MORPETH, NORTHUMBERLAND Where (location): Morpeth, market town in Northumberland, UK. On the banks of the River Wansbeck. When: 6th September 2008, the River Wansbeck breached its banks. The narrow steep topography of the Wansbeck Valley and increased urbanization caused exaggerated surface run-off and a lag time of only 8 hours. Causes: ~ River Wansbeck has tributaries in the uplands of rural Northumberland and flows through many small villages and towns along its course. ~ Environment Agency monitor river levels every 15 minutes ~ 150mm (6in) fell between Friday 5th and Saturday 6th October 2008 ~ 24 hours of prolonged heavy rainfall filled river channels and saturated the catchment area ~ Highest ever peak discharge recorded by the EA ~ Narrow steep drainage basin which encourages overland flow ~ 8 hour lag time ~ Confluence just north of Morpeth Effects: ~ 2000 homes flooded ~ People were being cared for at the Town Hall and local school. Many of them, especially the elderly, were distressed at having to leave their homes ~ 1000 people evacuated ~ RAF helicopter from nearby Boulmer airlifted the most vulnerable ~ “Staff from Castle Morpeth are handing out sandbags on a priority basis.” As the Environment Agency issued a flood alert for the whole of Morpeth ~ Major roadways in Durham and Northumberland were closed; with rural villages such as Powburn and Rothbury completely cut off and isolated. ~ The wet weather in the area at this time also affected Newcastle City Centre and sporting events such as the cricket at Durham. ~ Damage estimated to cost £10 million ~ Many homes and business are still unoccupied today Response: ~ Fire crews using inflatable dingies ferried families to safety ~ Morpeth Lions coordinate a Flood Victims Appeal and collect donations from Newcastle to Alnwick. ~ Morpeth Rotary Club shop has received over 300 donations of pieces of furniture. ~ Immediate needs were addressed by the Red Cross ~ Red Cross volunteers are systematically calling at houses, street by street. In this way, they can quickly identify those who have been adversely affected by the recent weather and ascertain what help they might need. ~ Red Cross fire and emergency support vehicles are stations in streets as a focal point for information. ~ Local Authorities help with the clean up and re-house residents in social housing ~ RNLI lifeboat crews from Newbiggin-by-the-sea, Amble and Blyth also assisted with evacuations Flood Management Methods Type of flood management Benefits of flood management Costs of flood management Cheap; easy to distribute Not very effective in large floods; not easy for elderly or people with disabilities to put in place Store very large volumes of water; can be used for multi-purpose schemes Very expensive; can lead to unwanted impacts such as increased tectonic activity, displacement of people, silting of dam Useful and flexible way of diverting flood waters away from centres of population Transfer the flood elsewhere; densely populated areas may not have total flexibility in location of relief channels Relatively cheap and easy way of protecting one or both sides of a river Do not protect against very large floods Sandbags Dams Relief channels Raised banks (levees) Unit 1: Dynamic Planet Specification Check List Unit 1 Topic 6: River Processes and Pressures SPECIFICATION CONTENT I know what erosion is I can describe how a rivers shapes its channel using 4 types of erosion I know what transportation is I can describe how a river transports its load (4 types) I can explain the formation of a waterfall I know what weathering is and can describe biological, physical and chemical weathering I know what mass movement is I know what a meander is and how it is formed I know what a flood plain is, where it is located and some pressures placed on the flood plain I can describe and explain the processes and features in the upper, middle and lower course of a river I can describe and explain a rivers long profile and cross section I can interpret storm hydrographs I can explain, using the hydrological cycle, factors that might cause flooding I know the causes and effects of one named flood event I can evaluate hard engineering strategies to prevent flooding and give examples I can evaluate soft engineering strategies to prevent flooding and give examples I can describe sustainable river management 37 ACTION Unit 1: Dynamic Planet Section C: Large-Scale Dynamic Planet Oceans on the Edge What you need to know: 1. Threats to the ocean 2. Ecosystem change 3. Increasing exploitation 4. Sustainable management . How and why are some ecosystems threatened with destruction? The term ecosystem describes a grouping of plants and animals that is linked with its local physical environment. The oceans, covering two-thirds of our planet, are home to marine ecosystem communities composed of fish, aquatic plants and sea birds- as well as tiny but very important organisms such as krill and plankton. HINT: make sure you are able to name some values of the Oceans e.g. its uses and value to human and animal life. TASK: make notes and research further the importance and value of CORAL REEFS AND MANGROVE SWAMPS. Pg 102-103. The way we use Oceans is becoming UNSUSTAINABLE this means we aren't treating/using it in a way that will preserve it for future generations. Within the oceans here is a natural balance between all life- these relationships form the FOOD WEB. Use page 104 to make a copy of the Oceanic food web. It is also important to consider the NUTRIENT CYCLE which is the movement and re-use of important substances e.g., nitrogen. DISRUPTION’S TO FOOD WEBS the main three disruptions you need to understand are: 1. Over fishing 2. Eutrophication 3. Siltation 4. Tourism 5. Pollution 6. Habitat destruction 7. Food web destruction Example: Overfishing of Krill – keystone species Eaten by: whales, penguins and fish. 38 Unit 1: Dynamic Planet Used for: Omega 3 supplements Fish farm food Southern Ocean food web is below – shows why is Krill so important? Climate change also disrupts the oceans. 1. Warmer water 2. More acidic water and bleaching 3. Higher sea levels Nutrient overloading The balance of nitrates, phosphates ammonia and chlorine is tipped and causes a loss of oxygen due to algal blooms. 39 Unit 1: Dynamic Planet 2. How should ecosystems be managed sustainably? There are two ways that marine ecosystems can be managed and that is again, as with the other units, at a LOCAL and GLOBAL SCALE. Case study on Firth of Clyde, Scotland (see next page to complete this activity). This is an example of where humans are putting pressure on the marine wildlife and there are plans to make the area more sustainable. SUSTAINABLE MANAGEMENT AT A LOCAL SCALE Managing coral reefs reefs are made of living animals, each piece contains polyp. They are part of a large colony of marine life. The polyp are skeletal creatures that form coral in clear, warm and sunlight seas. Coral reefs are home to ¼ of the world’s fish species. It also acts as natural barriers that protect the coastline from erosion. They are also great for tourism. However there are sustainability issues that come with this. Complete the case study6 on Coral Triangle on the case study section. SUSTAINABLE MANAGEMENT AT A GLOBAL SCALE Global actions are needed to tackle pollution and to save threatened species from overfishing and extinction. International Organisations play a large role in ensuring that the oceans are protected. The United Nations Food and Agriculture Organisations regulates the management of deep sea fisheries. Individuals around the world can also ‘do their bit’ by changing their shopping habits to ensure that we only buy sustainably sources fish and buy ‘dolphin friendly’ tuna. Pressures in the Firth of Clyde, Scotland page 109-111 The Firth of Clyde is a 60km stretch of water along Scotland’s West coast. It is home to 40,000 animal and microbe species. You can often see seals, harbour porpoises and basking sharks in this area. Leather back Turtles and Killer Whales are sometimes seen as well. So it is 40 Unit 1: Dynamic Planet obviously an extremely important ecosystem. Make notes on the 4 main pressures that humans put on this area. Which is the most severe and why? 1. Fishing 2. Tourism and leisure 3. Sewerage disposal 4. Military testing What is the impact of scallop fishing in Lamlash Bay? Locals views- what do the people think? Future Plans? Oceans on the edge 1. Using examples, describe the threats facing marine ecosystems (6) Foundation 2. Using named examples, explain the short and long-term threats facing marine ecosystems (6) Higher 41 Unit 1: Dynamic Planet 3. Describe the type of area a mangrove swamp might be found (2) 4. How can an undisturbed mangrove swamp support human activities? (2) 5. How could an increase in demand for one type of fish impact on the food chain? (6) 6. Explain how the change in ocean s=currents could impact marine ecosystems? (6) 7. Explain why the worlds oceans are under threat (4) 8. With reference to an example, explain the problems and successes of sustainable fishing (4) 42 Unit 1: Dynamic Planet 43 Unit 1: Dynamic Planet Battle for the Biosphere Glossary Biodiversity – is the range of animal and plant life found in an area. Biome – a world scale ecosystem. Biosphere – the zone where life is found. It extends 3m below ground to about 30m above ground and up to 200m deep in the oceans. Continentality – the effect of distance from the sea. Evapotranspiration – when water evaporates from the pores of leaves into the atmosphere. This results in water being drawn up plant stems. Indigenous Peoples – are people who have originated in and lived in a country for many generations. Keystone Species – a species that has a particularly large effect on other living organisms. Mass Extinction – the extinction of a large number of species within a short period of geological time. Pressure Belts – regions of the atmosphere that run around the earth. They are parallel to the equator. Some are high pressure areas, others are low pressure areas. Sustainable – means a process that does no lasting harm to people or the environment. Transnational Companies – are giant companies operating in many countries. Climate and Change Glossary Atmosphere – the layer of gases above the earth’s surface. Climate – the average of weather conditions measured over a period of 30 years. Climatologist – a scientist who is an expert in climate and climate change. Weather – the short-term day to day changes in things like temperature, wind, cloud cover and rainfall. 44 Unit 1: Dynamic Planet Desertification – the gradual change of land into desert. Extinction – a species of plant or animal dies out completely so none survive. Food Chain – plants provide food for plant eating animals (herbivores). Herbivores provide food for meat-eating animals (carnivores). Plants and animals and linked together and depend on each other. Glacial – a long period of time during which the earth’s glaciers expanded wildly. Interglacials – a long period of warmer conditions between glacials. Megafauna – means ‘big animals’. Most weighed over 40kg and included the woolly mammoth, giant elk, ground sloth, sabre-tooth cat, giant beaver and glyptodon. Milankovitch Cycles – the three long term cycles in the earth’s orbit around the sun. Milankovitch’s theory is that glacials happen when the three cycles match up I a certain way. Quaternary – the last 2.6 million years, during which there have been many glacials. Stratosphere – the layer of air 10 – 50km above the earth’s surface. It is above the cloudy layer we live in, called the troposphere. The Greenhouse effect – the way that gases in the atmosphere trap heat from the sun. The gases act like the glass in a greenhouse. They let heat in but prevent most of it from getting out. Restless Earth Convection Current - When heat rises from the core it creates convection currents. These currents are strong enough to move tectonic plates on the Earth’s surface. Tectonic plate - The Earth’s surface is broken into many large pieces, like a cracked eggshell. These different pieces are called tectonic plates. Plate Boundary - The point at which two tectonic plates meet Conservative boundary - When two plate boundaries are sliding alongside each other (causing earthquakes). 45 Unit 1: Dynamic Planet Conservative boundary - When two plates are moving apart from each other and new crust is created. Destructive boundary - When two plates are moving towards each other and crust is destroyed. Oceanic crust - The part of the Earth’s crust which is under the oceans. Continental crust - The part of the Earth’s crust that makes the continents. Pangaea - A supercontinent consisting of the whole land area of the globe before it was split up by continental drift. Volcano - A landform built up from lava and ash. Volcanoes come in many different forms. Lava - melted rock that erupts from a volcano. Magma - Melted rock below the Earth’s surface. Stratovolcano - A cone shaped volcano formed when layers of ash and lava build up. Earthquake - A sudden release of energy between two plates. Focus - The point at which an earthquake occurs in the ground. Epicentre - The point directly above the focus on the Earth’s surface. Magnitude - The strength of an earthquake. Richter scale - The scale on which we measure the magnitude of an Earthquake. Evacuate - When people move from a place of danger to a safer place. Water world Hydrosphere - All of the water close to, or on, the surface of the Earth. Closed system - A system which repeats continuously with no inputs or outputs e.g. the hydrological cycle. Open system - A system which involves inputs and outputs. Hydrological Cycle - The movement of water between its different forms e.g. gas, (water vapour) liquid and solid (ice) forms. 46 Unit 1: Dynamic Planet Biosphere - The zone in which life is found. Lithosphere - The outer layers of the Earth’s surface (the crust and the upper mantle). Precipitation - Moisture which falls from the sky including rain, snow, sleet, fog, mist and hail. Evaporation - The changing of a liquid into a vapour or gas. Interception - The capture of rainfall by leaves. Infiltration - Movement of water into the soil from the surface Percolation - Water flows vertically through soil and rocks Groundwater storage - Water stored in rocks following percolation Transpiration - Water vapour is released through the stomata in leaves Throughflow - Water flows horizontally through the soil into the river Surface runoff - Water flows horizontally over the land into the river Saturation - When soil is full of moisture Water Table - The level at which saturation occurs in the ground or soil. Input - Things which enter a system Output - Things which leave a system Stores - when something is held within a system Transfers or flows - movements within the system Water Stress - Occurs when the demand for water exceeds the amount that is available during a certain period. Scarcity -Shortage of water due to either physical or economic constraints. Eutrophication - The process by which ecosystems, usually lakes, become more fertile as fertilizers and sewage flow in. The resultant loss of oxygen in water kills off all species that need oxygen to survive e.g. fish. 47 Unit 1: Dynamic Planet Overabstraction - the name given when too much water is being taken from the river, lake or another water source. NGOs - Non-governmental Organisations e.g. WaterAid. 48