AQA GCSE Geography Revision Guide PDF

AQA GCSE GEOGRAPHY Provided by The Coleshill School REVISION GUIDE For the grade 9-1 GCSE examinations  Contents Paper 1 Physical: Living with the Physical Environment Th...

AQA GCSE GEOGRAPHY Provided by The Coleshill School REVISION GUIDE For the grade 9-1 GCSE examinations  Contents Paper 1 Physical: Living with the Physical Environment The Challenge of Natural Hazards Tectonic Hazards (Volcanoes & Earthquakes)....................................................... 1-6 Weather Hazards (Tropical Storms and UK Extreme Weather).................................. 7-12 Climate Change.................................................................................... 13-16 The Living World Ecosystems........................................................................................ 17-19 Tropical Rainforests.............................................................................. 20-24 Hot Deserts....................................................................................... 25-29 Physical Landscapes of the UK Coasts.............................................................................................. 30-37 Rivers.............................................................................................. 38-45 Paper 2 Physical: Challenges of the Human Environment Urban Issues & Challenges Urbanisation........................................................................................... 46 NEE City Case Study (Rio de Janeiro)........................................................... 47-49 UK City Case Study (Birmingham)................................................................ 50-54 Sustainable Cities................................................................................. 55-56 The Changing Economic World Development....................................................................................... 57-61 Economic Development in a NEE Country (Brazil)............................................... 62-65 Economic Development in the UK................................................................ 66-72 The Challenge of Resource Management Distribution of Food, Water & Energy in the UK............................................... 72-75 Energy.............................................................................................. 76-80 1  Paper 1 Section A NATURAL HAZARDS What is a natural hazards? What are the main types of hazard? Meteorological 1) An event becomes a hazard when it Geological Hazards Hazards affects people Geological Hazards Meteorological 2) A natural hazard is a natural process are caused by land Hazards are caused by which could death, injury or disruption and tectonic weather and climate. to humans, or destroy property and processes. Examples Examples are tropical possessions. include volcanoes, storms and flooding 3) A natural disaster is an event that has earthquakes and caused by extreme actually happened. landslides weather. Hazard Risk is the probability that a natural hazard What affects a countries ability to cope? occurs. There are 3 main factors affecting risk: Vulnerability Capacity to Cope 1) The more people that are in areas 1) Natural Hazards have to affect human exposed to natural hazards, the activities to count as a hazard. The greater the probability they will be better a population can cope with an affected by a natural hazard. So extreme event, to lower the threat hazard risk is higher 2) EG: HICs are better able to cope with 2) EG: People living at the base of a earthquakes as they can build volcano in Naples, Italy are vulnerable earthquake proof buildings and repair to eruptions the damage afterwards. Nature of Natural Hazards 1) Type – the hazard risk from some hazards is greater than others (eg tropical storms can be predicted but earthquakes can’t. 2) Frequency – Some natural disasters occur more often than others (eg flooding) 3) Magnitude – More severe natural hazards cause greater effects than less severe events. Eg a magnitude 5 earthquake compared to a magnitude 8 Tectonic Plates The Earth’s surface is 1) The inner core is solid and outer liquid separated into Tectonic 2) Around the core is the mantle - semi molten rock moving slowly Plates 3) The outer layer is the crust and the crust is divided into slabs called tectonic plates. These plates can either be continental or oceanic plates. Where they meet is called a plate boundary/margin. 4) The plates move due to convection currents in the mantle. 2  How do the plates move? What are convection currents? 1) Heat rising and falling inside the mantle creates convection currents generated by radioactive decay in the core. 2) The convection currents move the plates. 3) Where convection currents diverge near the Earth's crust, plates move apart. Where convection currents converge, plates move towards each other. The 4 main Plate Boundaries Destructive Plate Boundary 1) Destructive Plate margins are where two plates are moving toward each other 2) When a heavier oceanic plate meets a continental plate it is forced down (subducted) into the mantel and melted (DESTROYED). This rising heat from the melting plate causes volcanoes. The ‘scraping’ of the plate as it is subducted is what causes earthquakes Conservative Plate Boundary 1) Conservative Plate margins are where two plates are sideways past each other 2) As the plates move past each other they can cause friction, and as this friction builds and released, earthquakes occur Constructive Plate Boundary 1) Constructive Plate margins are where two plates move away from each other 2) Magma rises from the mantle to fill the gap and cools, CONSTRUCTNG new crust. Collision Plate Boundary 1) Collision Plate margins are where two plates move toward each other. 2) As both are continental crusts, one cannot be forced down, so both are pushed upwards forming ‘fold’ mountains 3) An example is the Himalayas and earthquakes happen here. (eg our Nepal case study) 3  Volcanoes and Earthquakes Where do volcanoes occur? Sixty percent of all active volcanoes occur at the boundaries between tectonic plates. Most volcanoes are found along a belt, called the “Ring of Fire” that encircles the Pacific Ocean. Some volcanoes, like those that form the Hawaiian Islands, occur in the interior of plates at areas called “hot spots.” Volcanoes occur at Destructive and Constructive Plate Margins Earthquakes occur at all 4 plate margins Where do earthquakes occur? Earthquakes are caused by the tension that builds up at all 3 plate margins Destructive Plate Margin: Earthquakes occur when the subducted oceanic plate scrapes against the continental as it slides underneath Constructive Plate Margins – tension builds along cracks within the plates Conservative – Tension builds when plates sliding past each other get stuck The plates eventually jerk past each other causing shockwaves. The shockwaves spread out from the focus (the point in The Moment Magnitude Scale measures the amount the earth where the of energy released by an earthquake (called earthquake starts) magnitude) [we used to call this the Richter Scale] If the focus is shallow then The Moment Magnitude Scale is logarithmic – so a the waves are stronger and magnitude 7 earthquake (like Nepal) is 10 times more cause more damage powerful than a 6 (like New Zealand) The epicentre is the point on the earth’s surface directly Earthquakes and Volcanoes have many serious effects: above the focus Primary Effects: Immediate effects of a disaster (ie impacts of the ground shaking in an earthquake) Secondary Effects: Happen later on, often as a result of the primary effect. Primary & Secondary Effects 4  Tectonic Hazards- LIC & HIC Contrasting Examples 1) Earthquake in Nepal, a lower income country: 2) Earthquake in New Zealand, a HIC country: Place: Gorkha, Nepal Place: Christchurch, New Zealand Date: April 2015 Date: February 2011 Size: 7.8 on the moment magnitude scale Size: 6.3 on the moment magnitude scale 8841 died, mostly from collapsed buildings 181 died, mostly from 1 collapsed TV 16 800 injured building Primary 1 million made homeless 2,000 injured 7000 schools, 26 hospitals and Dharahara 80% of the city without power Tower (UNESCO site) destroyed 50% of all buildings severely damaged Loss of income from a reduction in Triggered an avalanche on Mount Everest Secondary tourist numbers as Christchurch could which swept through the base camp no longer host rugby world cup matches Loss of income from a reduction in tourist Schools were closed for 2 weeks numbers due to damage to historical 1/3 of residents faced financial buildings, hotels and transport. difficulties for up to 3 months after Rice seed stores wiped out, 2/3 of population the event. depend on this The Australian Government donated International help requested in the form of NZ$6.7 million to the Red Cross appeal rescue teams 27000 chemical toilets were flown into Immediate Responses Temporary shelters set up and food, water the area as sanitation and sewerage and medical supplies were distributed to works were damaged worst affected areas 7 million in international aid was provided Facebook launched a safety feature so The New Zealand Defence Force people could indicate that they were safe in provided equipment, transport, difficult to reach terrain. evacuation, food and water aid to 1000 Several companies didn’t charge for phone homeless people as a result of the calls earthquake 23 areas identified for rebuilding in post Insurance companies paid $898 million in Long Term Responses disaster assessment claims. Mount Everest reopened to tourists in Water & Sewage was restored by August August after some trails were rerouted, 80% of roads were repaired within 6 climbing permits were also extended until months) 2017 Long Term Temporary Accommodation UN trained farmers to expand crop was provided by the New Zealand production and maintain and repair irrigation Government to the 10,000 made channels that were damaged by landslides homeless GCSE Practice Question: Assess the extent to which primary effects 5 are more significant than secondary effects.’ (9)  Living with Tectonic Hazards Why do people live in areas at risk from natural disasters? They’ve always lived there – moving away would mean leaving friends and family They’re employed in the area – moving way would mean having to find new jobs They’re confident in the support they would receive from their government after a disaster Some people won’t think that severe earthquakes or volcanoes won’t happen in their lifetime The soil around volcanoes is fertile because it’s full of minerals from volcanic ash and lava. This makes it good for farming Volcanoes are tourist attractions bringing visitors so jobs are provided in the tourist sector. Volcanoes can provide free energy through geothermal sources. How can we manage tectonic hazards? Monitoring 1) Networks of seismometers and lasers monitor earth’s movements and can be used in early warning systems to give a small but vital warning before an eruption. 2) Remote Sensing – Satellites detect heat and changes to the volcanoes shape 3) Scientists can monitor the tell-tale signs that come before an eruption. Such as tiny earthquakes, escaping gas and changes to the shape of the volcano. (eg bulge in the side of the crater where magma is building up. Prediction 1) Earthquakes are difficult to predict, as they often occur without warning. However the general location of likely quakes is known, as they occur along plate margins. 2) Sensitive seismometers are used to measure the minor tremors and foreshocks that sometimes occur before quakes. 3) Volcanic eruptions can be predicted if the volcano is well monitored. Predicting when a volcano is going to erupt gives people time to evacuate Planning 4) Future developments can be planned to avoid the most at risk areas (called Land Zoning). 5) Emergency Services can train and prepare for disasters 6) People can be educated so that they know what to do if a disaster happens 7) Governments can plan safe evacuation routes to get people out quickly 8) Emergency supplies like blankets and ‘meals ready to eat [MRE] can be stockpiled. 6  Protection 9) Buildings can be designed to withstand earthquakes, eg by using materials like reinforced concrete or building special shock absorbing foundations that absorb the earthquakes energy 10) Existing buildings and bridges can be strengthened (eg by wrapping pillars in steel frames) so they’re less likely to collapse 11) Automatic shut off switches can be fitted that turn off gas and electricity supplies to prevent fires. GCSE Practice Question: Explain how volcanoes can be monitored and eruptions predicted.. GCSE Practice Question: Explain, using examples, why people might choose to live in areas at risk from tectonic hazards.. Global Atmospheric Circulation There’s an overall movement of air between the equator and poles that affects the Earth’s climate, this movement is called Global Atmospheric Circulation The main cell to know is the Hadley Cell Here’s how it works: At the equator the ground is intensely heated by the sun This causes air to rise creating low pressure, air separates and moves towards the poles. When it reaches 30º north & south of the equator air cools and sinks, causing a high pressure zone. Global Atmospheric Circulation causes As air sinks it becomes warmer and drier areas so have some types of weather with low rainfall. This is where deserts are more than others. For example, the UK found, on the Tropic of Cancer has a lot of low pressure systems from When air is sinking, this is HIGH Pressure the Atlantic that bring wet and windy When air is risking, this is LOW Pressure weather 7  Tropical Storms Tropical Storms are intense low pressure weather systems with heavy rain and strong winds that spiral around the centre. They can be called Hurricanes, Typhoons or Cyclones depending on where they occur. How do tropical storms form? Sequence Air is heated above warm tropical oceans. Air rises under low pressure conditions. Strong winds form as rising air draws in more air and moisture causing torrential rain. Air spins due to the Coriolis effect (spin of the earth) around a calm eye of the storm. Key Information Cold air sinks in the eye so it is clear and They only form in ocean temperatures over dry. 27 °C, Heat is given off as it cools powering the A storm becomes a tropical storm once storm. winds hit 74mph Storms are recorded on the Saphir Simpson On meeting land, it loses source of heat scale, 1-5. and moisture so loses power. They are only found in latitudes of 5-20 degrees north and south of the equator. The strongest part of the storm is the eye wall, where winds are fastest The centre of the storm is called the eye and is calm. Climate Change & Tropical Storms Global Temperatures are expected to rise as a result of climate change, so more of the world’s oceans will be above 27. This means more places will experience tropical storms Oceans will stay above 27 for longer so tropical storm seasons will last longer Higher sea temperatures also mean storms will be stronger 8  Tropical Storms- Effects and Responses Case Study – Hurricane Katrina The effects of Hurricane Katrina were severe, particularly in the New Orleans where wind speeds reached 150mp/h making it a Category 5 and caused flood defences to fail. Hurricane Katrina struck the New Orleans, USA on 28th August 2005 Primary Impacts Secondary Impacts 1800 died 1) Total cost of the damage was an estimated $150 300,000 houses were destroyed leaving 1 billion. million homeless 2) 230 000 jobs were lost from damaged businesses Large areas were flooded, including 80% of 3) Looting was rife, due to lack of food and supplies New Orleans. 4) The storm caused oil spills which resulted in over 3 million people were left without 26 million litres of oil being leaked electricity. 5) Water supplies were contaminated by sewage and 15 metre storm surge caused flooding and chemicals overtopping of the levees 6) Airport was badly damaged and roads were Bridges on the major US 90 highway were blocked by flood waters which made rescue destroyed making access into the city efforts and deliveries of supplies difficult difficult 7) Katrina destroyed 30 oil platforms which cost the 1.3 million acres of forest land were country billions destroyed costing about $5 billion There were immediate and long term responses to these effects 1) 70-80% of New Orleans residents were evacuated before the hurricane reached land. 2) Mississippi and Louisiana declared states of emergency they set up control centres and emergency shelters assisted with search and rescue and aid delivery Immediate Responses 3) 10,000 army troops were stationed in the area to assist with relief 4) International aid was sent, this included food, water and medical supplies. The Red Cross has provided 902 shelters for 100,000 people 5) 20 000 people were evacuated, many to the Superdome, an indoor stadium 6) The Federal Government and FEMA delivered 17 million MRE’s (Meals Ready to Eat) 1) The Senate passed a bill deliver £5 billion funds to repair storm-damaged sewage treatment and drinking water plants within 2 years. Long Term Responses 2) Rebuilding of flood defences costing $14.5 million. 3) FEMA provided housing assistance (rental assistance) to more than 700,000 applicants 4) Congress provided $17 billion to re build homes and infrastructure 5) Thousands of homes rebuilt away from areas at risk from coastal flooding by storm surges GCSE Practice Question: Assess the extent to which tropical storms have effects on people and the environment using an example you have studied (9 marks) 9  Tropical Storms- Reducing their effects Monitor Using technology to identify the formation of tropical storms and track their paths and strengths Satellites monitor the cloud pattern and can detect as the winds become more organised, into a spiral pattern and the eye develops. Prediction Scientists use computer models that use data from satellites to calculate a path for the storm Scientists use radar and aircraft to help monitor and predict the path of storms. Predicting the path gives people time to evacuate and board up homes. Planning Future developments, eg new houses, can be planned to avoid the areas at most risk. Emergency services can train and prepare for disasters. Eg practising how to rescue people from flooded areas with helicopters Governments can plan evacuation routes to get people away from storms quickly. Actions taken before a hazard strikes to reduce its impact, such as educating people in evacuation plans can reduce deaths. Families are encouraged to plan what they need to do and have in the event of a tropical storm: Disaster supply bag, fuel in vehicles, know where evacuation shelters are, storing loose objects. Protection Build hurricane proof homes and installing storm shutters on houses, e.g. in Florida, Sea walls can built to protect key infrastructure from storm surges and storm drains can be designed to take away heavy rainfall Tropical cyclone shelters in Bangladesh have helped reduce the death toll from 500 000 deaths in 1970 to 4234 in 2007. Houses built on stilts to allow storm surge to pass underneath Salt marsh, wetlands and mangroves replanted provide natural protection from storm surges. (These ecosystems are often destroyed to make way for agriculture and building development). GCSE Practice Question: Explain why planning and being prepared is the best option for reducing the effects of tropical storms (4 marks) 10  Extreme Weather in the UK Extreme weather is when weather is significantly different from the usual weather pattern. So a heatwave in the UK will look very different to a heatwave in Australia for example! Weather hazards are quite common in the UK – and it’s not just rain… The UK experiences lots of extreme weather hazards Weather in the UK is becoming more extreme Extreme Weather 1) Temperatures have become more extreme in recent years. December 2010 was the coldest for over 100 years, with snow and ice causing several death and school and road closures. Just 4 months later April 2011 was the warmest ever!!! 2) It is raining more – more rainfall records have been broken since 2010 than in any other previous decade on record. 2013 was the wettest year, with December 2015 the wettest month ever! 3) Major flooding occurs often. In 2014 there was a major flood caused by storms and high rainfall in Somerset. This winter 2014 storm meant the UK experienced its wettest winter since records began in 1760. 2014 also saw the UK experience its stormiest weather for 20 years with over 20 major storms occurring. The year was also the warmest on record (until 2015) Climate change can increase the frequency and intensity of extreme weather events. Flooding, for example is becoming more frequent in the UK as a warmer atmosphere can hold more moisture. 11  Extreme Weather in the UK Winter 2013/14 were extremely stormy Case Study – 2003 UK Heatwave Causes Low Rainfall - Rainfall over much of the UK was below The heatwave affected all of the UK. The what is normally expected during the months of record temperature, of over 38.1C June, July and August. High Pressure - The long- (100.6F), was recorded in Gravesend, Kent, lasting high pressure system tended to reduce the SE England amount of rain that fell. High pressure areas usually bring little cloud and warm conditions in summer GCSE Practice Question: Using an Social Impacts. example of a recent extreme 1) +2,000 deaths were attributed to the heat weather event in the UK, assess 2) +20 people injured by lightning strikes brought by whether the socio-economic thunderstorms. effects were more severe than the 3) Increase in people experiencing breathing environmental effects. difficulties, poor air is suspected to account for 1/3 of deaths 4) Elderly suffering from heat exhaustion. Environmental Impacts Economic Impacts 1) Air pollution - it is thought that one third 1) +Transport - some railway tracks buckled in the of the deaths caused by the heatwave in heat meaning a 30mph speed restriction was the UK were caused by poor air quality. imposed affecting commuters. 2) Forest Fires destroyed ecosystems and 2) The London Underground became unbearable habitats meaning people unable to travel to work. 3) Severe impacts on crop yields; wheat fell 3) Road surfaces melted effecting deliveries. 12% in 2003 in the UK 4) Low river levels prevented some boats from sailing 4) Many natural animals to die affecting affecting tourism income. ecosystems, fish stocks were lowered in 5) Major increase in UK tourism – an extra 1000 rivers. Over 1000 farm animals, mainly people packed onto Brighton beach for example cows and pigs, were also lost 6) Farming Industry lost £13 billion due to crop failure Management Strategies can Reduce the Risk from Weather Hazards The 2003 Heatwave could have been much worse if there weren’t strategies to reduce the risk: 1) PREDICTION- warning systems, such as weather reports and heat warnings issues by the Met Office and Environment Agency (including 40 severe flood warnings) gave people time to prepare 2) PROTECTION- individuals and local authorities prepared for extreme weather before it happened. Workers altered their working hours. Some refuse collectors started earlier to pick up rapidly decomposing rubbish 3) PLANNING- emergency services and local councils planned how to deal with extreme weather events in advance. Department of Health launched a project called the Heat-Health Watch which now gives advanced warning of UK hot weather. Public water supply shortages occurred, which led to a temporary ban on using hose pipes. 4) 12  Climate Change – The Evidence There’s information stored in thick ice sheets, tree rings and pollen that scientists can use to find out what the earth’s climate was like 1000s of years ago Ice Cores 1) Ice sheets are made up of layers of ice – on layer is formed each year 2) Scientists drill into ice sheets to get long cores of ice 3) By analysing all the gases trapped in the layers of ice, they can tell what the temperature was each year. 4) One Ice core from Antarctica showed us how the temperature has changed over the last 400,000 years. Temperature Records 1) Since the 1850s global temperatures have been measured accurately using thermometers. This gives a reliable but short term record of temperature. Pollen Analysis 1) Pollen from plants gets preserved in sediment, eg at the bottom of lakes. 2) Scientists can identify and date the preserved pollen to show which species were living at that time. 3) Scientists know the conditions that plants live in now, so preserved pollen from similar plants shows that climate conditions were similar. Tree Rings 1) As a tree grows it forms a new ring each year – the tree rings are thicker in warm, wet conditions. 2) Scientists take cores and count the rings to find the age of a tree. The thickness of each ring shows what the climate was like. 3) Tree rings are a reliable source of evidence of climate change for the past 10,000 years. The Earth is getting warmer Climate change is any significant change in the Earth’s climate over a long period. The climate is constantly changing, and always has. However, recently, the earth is seeing a rapid increase in global temperatures. This is called global warming. This sharp rise in global temperatures over the last century is a human induced climate change. 13  Climate Change – The Causes Climate change goes back long before humans roamed the earth. Some natural factors cause climate change, but in the last 150 years or so, human activities have begun to change the climate too. What are the Natural Causes of Climate Change? Orbital Changes The way the earth moves around the sun changes. Those changes affect the amount of solar radiation (sun energy) the earth receives. If the earth orbits closer to the sun, like the red orbit on this diagram, the climate will be warmer Orbital changes affect the glacial periods of ice ages Volcanic Activity Solar Output Major volcanic eruptions eject large The Suns output of energy always changes quantities of ash into the atmosphere. (every 11 years) Some of these ash particles reflect and When the sun has more energy (which can block the sun’s rays, cooling the earth be witnessed through sun spots [darker surface. areas on the sun]) the climate is warmer What are the Human Causes of Climate Change? Burning Fossil Fuels The Greenhouse Effect CO2 is released into the atmosphere 1) The rate of recent rise in global temperatures is when fossil fuels like coal, oil and gas are alarming burnt. (eg from power stations) 2) There is scientific agreement that human activities are causing global warming through the Farming greenhouse effect. 3) The greenhouse effect is when greenhouse gases, Farming of livestock produces a lot of such as CO2 absorb outgoing heat so less heat is methane lost and some is reflected back to earth. Rice paddies contribute to global warming 4) Too much greenhouse gas in the atmosphere because flooded fields emit methane means too much sun energy is trapped and the planet warms up. Deforestation Plants remove C02 from the atmosphere and convert it into organic matter. When trees or plants are chopped down, the stop taking in CO2 CO2 is also released when trees are burnt as fuel or when removed using ‘slash and burn’ 14  Climate Change – The Effects Climate Change effects the environment…. Environmental Effects Warmer temperatures are causing glaciers to shrink and ice sheets like Greenland to melt. This melted water goes into the sea, causing sea levels to rise Sea ice is also shrinking, leading to the loss of polar habitats. Rising sea levels means low-lying and coastal area, like Bangladesh, will be flooded more often. Coral reefs are dying as sea temperatures rise (called Coral Bleaching) Precipitation (rain) patterns are changing. More warmth = more hot air rising = more rain Some habitats are being destroyed and this is effecting biodiversity and causing extinctions. And it affects humans too … Effects on humans Increased disease eg. skin cancer and heat stroke. Winter deaths decrease with milder winters. Crop yields affected by up to 12% in South America but will increase in Northern Europe but will need more irrigation. -Less ice in Arctic Ocean increases shipping and extraction of oil and gas reserves. -Droughts reduce food and water supply in sub- Saharan Africa. Water scarcity in South and South East UK. -Increased flood risk. 70% of Asia is at risk of increased flooding -Declining fish in some areas affect diet and jobs. -Increased extreme weather - Skiing GCSE industry Practice in Alps Give Question: threatened. two pieces of evidence, other than the change in global temperature, that show climate change has taken place. (4) GCSE Practice Question: ‘Humans are to blame for climate change.’ To what extent do you think this statement is true? ; 15  Climate Change – Management Various strategies aim to reduce the causes of climate Mitigation Strategies change, by reducing the concentration of greenhouse Carbon Capture gases in the atmosphere. Alternate Energy Carbon Capture (CCS) is a new technology that involves Replacing fossil fuels with nuclear power and capturing CO2 and storing it renewable energy will reduce greenhouse gasses deep underground. In the UK, more offshore windfarms are being built, and tidal power projects are planned. International Agreements Planting Trees In 2015 most countries in the world agreed to monitor and Planting trees increases cut greenhouses gases by signing the Paris Agreement the amount of CO2 that is Each country was set a target to cut emissions. The EU absorbed as trees act as a agreed to cut emissions by 20% by 2020. carbon sink Adaption means responding to changes caused by climate change. Adaption Strategies Changing Agriculture Systems Changing rainfall patterns and higher temperatures will affect the productivity of existing farming practises. 1) It may be necessary to plant a new type of crops that are more hardy and suitable for harsh conditions. 2) In some regions, biotechnology is being used to create new crop varieties which are more resistant to extreme weather. Managing Water Supply Coping with Sea Level Rise Dry areas are predicted to get drier, Dry areas are predicted to get drier, leading to water shortages, leading to water shortages, 1) Water meters can be installed in 1) Physical defences such as flood barriers people’s homes to discourage use. are being built (Thames Barrier -London) 2) Rainwater can be collected and 2) In LIC countries, with less money, waste water can be recycled to make houses are being built on stilts and flood more water available shelters are being built. GCSE Practice Question: ‘To what extent is mitigation better than adaptation in tackling climate change? 9 marks 16  Paper 1 Section B LIVING WORLD What is an Ecosystem? An ecosystem includes all the living and non-living parts in an area A food chain shows what eats what. A food web shows lots of food chains and how they overlap. When dead material is decomposed, nutrients are released into the soil. The nutrients are then taken up from the soil by plants. The plants may be eaten by consumers. When the plants or consumers die, the nutrients are returned to the soil. This transfer of nutrients is called the nutrient cycle A change to one part of an ecosystem has an impact on other parts Some parts of the ecosystem depend on the others, eg consumers depend on producers for a source of food and some depend on them for a habitat. So, if one part changes it affects all the other parts that depend on it. Here is an example…. GCSE Practice Question: ‘Describe a food chain for a chosen small-scale ecosystem in the UK. (4 marks) 17  Sutton Park: A Local Ecosystem Case Study Human uses for woodland Location Sutton Park is a 2,400 acre National For recreation - for example for walks Nature Reserve located 6 miles For conservation to protect ecosystems north of the city centre of B’ham. As a resource - wood is used for fuel (firewood) or as It’s is a National Nature Reserve timber for buildings, Sutton Park has a complex food web composed of Sutton Park’s Food Web thousands of species, as the result of its careful management A wide variety of native tree species that include oak and ash. A shrub layer consisting of hazel and holy, along with grasses, brambles, fern and bracken Many primary consumers including insects, small mammals, grazing cows and 38 species of bird. Secondary consumers such as owls, adders and foxes Over 10 lakes and ponds providing important habitats for numerous species of fauna (animals) and flora (plants) Sustainable Management In 1989, work began to restore the heathlands. Large areas of birch trees and gorse were cleared from areas that should be open heathland. This work continues today. Low level intensity grazing will help to preserve the health of the heathland into the future. Tourist Management Strategies: Providing car parks, toilets, park rangers and maintaining footpaths to manage recreation. Providing three easy-access car parks for people with disabilities. Preserving ancient earthworks and buildings. Other Sustainable Management Strategies Allowing old trees to die and collapse naturally (unless they're dangerous) Encouraging grazing (there's a herd of 50 cows) to maintain the grassland Maintaining ponds & lakes to prevent them silting up. Preserving the herd of fallow deer. Dead wood is generally left when it falls in the forest, as it provides a valuable habitat Some grassy areas are left uncut to encourage wildlife like butterflies. Human activity can have many impacts on ecosystems. Once one component has been changed it can have a serious knock on effect on the ecosystem. Threats to the Ecosystem 1) Due to human management and tourism, lots of the natural woodland & heathland was destroyed for park land 2) Changes to grazing in Sutton Park have contributed to invasion by birch, gorse and bracken. Most of the areas covered in birch trees were open heathland up until 1976. 3) Lack of grazing led to birch seedlings becoming established and coverage of large areas of heathland with woodland. 18  Global Ecosystems 1) The climate in an area determines what type of ecosystem forms. So different parts of the world have different ecosystems because they have different climates. 2) The map below shows the global distribution of 6 global ecosystems Tundra Grassland Found at high latitudes. Winters are There are 2 types of grassland. Savannah grasslands very cold, summers are brief and little are found between the tropics. These are dry with rainfall. There are few trees, and wet seasons with trees and grass. Temperate vegetation is mainly moss and grass. grasslands are found at higher latitudes when there There is a layer of permanent frozen is more variation in temperature and less rainfall. ground called permafrost There are no trees here, just grass. Temperate Deciduous Forest Tropical Rainforest Found mainly in the mid latitudes where Found around the there are 4 main equator, between the seasons. Summers are tropics, where it is hot warm, winters are mild and wet all year round. and it rains all year. Convectional rainfall Deciduous tress lose and sun make it ideal their leaves in winter for vegetation growth to cope with cold weather. Hot Deserts Polar Found between 15 and 35 degrees north and south of Found around the north and south the equator where there is little rainfall. Formed due poles. They are very cold, icy and dry. to Hadley cell (see page 6). It’s very hot during the Not much grows at all. They remain day and very cold at night, so is a place of extreme dark for several months each year so temperatures. Shrubs and cacti are sparsely the growing season is very short – distributed in the sandy soil about 2 months. GCSE Practice Question: ‘Describe the global distribution of the tropical rainforest ecosystem. (3 marks) 19  Tropical Rainforests The tropical rainforest is a hot, wet ecosystem found on and near the Earth's equator. Tropical rainforests contain far more species of plants and animals than any other biome. They cover approximately six per cent of the Earth's surface, and because they get 2,000 mm of rain per year and temperatures range from around 27 to 32°C, conditions are wet and hot all year round so it is a good environment for growth. Why is it hot & wet in a rainforest? The sun’s rays shine directly on the land and sea at the equator, so it is the hottest part of the earth. The sun’s heat warms the land, the air and the sea and causes water to evaporate into the air. The warm air can hold a lot of water. As the air rises it cools and the water turns back into rain, creating clouds. This means that there is lots of rain in the forests around the tropics. The emergent layer The tallest layer - over 40 metres. Contains only a few What is the structure of tall trees which grow taller than the trees of the canopy. The plants are made for living in dry conditions the Rainforest? because it’s very sunny. They have small, waxy leaves to prevent them drying out. Canopy The second highest layer - 30-45 metres. The canopy blocks out the sun from lower layers and intercepts (catches) rainfall. It contains the most plant species. This layer contains the most animal species. Understory Low light conditions (2-15%). Plants adapted to low light grow here. Birds, butterflies, frogs, snakes and lots of insects live here. Forest floor Very little light reaches the forest floor (2%) - so plants grow slowly. The ground is covered in fallen leaves, rotting branches and twigs and a network of shallow roots. Lots of insects live here. 20  Tropical Rainforests - Adaptations Rainforests have extremely high biodiversity. They contain around 50% of the world’s plant and animal species. How have plants adapted? 1. Thick, waxy surface of leaves protects against hot sun, heavy rain, and Leaves strong winds 2. Epiphytes are plants which live above the ground growing on tree trunks Epiphytes and branches, Example orchids, ferns, mosses 3. Wide roots stop these enormously tall trees from falling over. They also Buttress wind above the ground looking for food and nutrients rather than digging roots beneath the ground where nutrients are scarce. 4. Tree The trees don’t waste time growing branches as they could use this energy trunks to grow faster and reach the sunlight first! 5. Lianas Lianas are climbing woody vines that drape rainforest trees. They have adapted to life in the rainforest by having their roots in the ground and climbing high into the tree canopy to reach available sunlight 6. Drip These leaves allow rain drops to run off quickly. Plants need to shed water Tip to avoid growth of fungus and bacteria in the warm, wet tropical rainforest leaves How have animals adapted? 1. Sloths The sloth uses camouflage and moves very slowly to make it difficult for predators to spot. They feed at night when it’s cooler which helps them save energy. 2. Spider The spider monkey has long, strong limbs to help it to climb Monkey through the rainforest trees. 3. Flying The flying frog has fully webbed hands and feet, and a flap frog of loose skin that stretches between its limbs, which allows it to glide from plant to plant. 4. The toucan has a long, large bill to allow it to reach and cut Toucan fruit from branches that are too weak to support its weight. GCSE Practice Question: ‘Explain how tropical rainforest vegetation adapts to the climate’ (4marks) 21  Tropical Rainforests – Deforestation The removal of trees from forests is called deforestation. It’s happening on a huge scale in many tropical rainforests. Deforestation has many impacts – some good and some bad!! What are the main threats to Tropical Rainforests? Environmental Impacts Why does Deforestation still occur in Brazil? What are the environmental impacts? What is deforestation worth to Brazil? With no trees to hold the soil 1) Brazil is the world's biggest beef producer, and together, heavy rain washes away the it exported a record 1.64 million tonnes of the soil (soil erosion). animal product last year. Total revenue for beef Without a tree canopy to intercept and leather came to about $7.6 billion. rainfall and tree roots to absorb it, 2) Soybeans are Brazil's biggest export — it more rain reaches the soil. This exports $25 billion of the commodity each year. reduces soil fertility as nutrients are 3) Mineral exports (including gold and iron) were washed away. worth $36.6 billion to the Brazilian economy - Trees are a carbon sink as they absorb 20% of all Brazil’s exports. CO2, and burning trees release CO2, 4) Total export value of primary timber products so deforestation releases greenhouse in 2015 was about $243.2 million. gases into the atmosphere 5) Brazil intends to increase exports by about 20% Deforestation is responsible for 15% in the next four years of global CO2 emissions. 22  Tropical Rainforests – Amazon Case Study The Amazon is the largest rainforest on earth, but it’s shrinking due to deforestation. Why is Deforestation a problem in the Amazon? 1) The Amazon covers an area of around 8 million km2 and is mainly found in Brazil (and Peru) 2) Since 1978, over 750,000 km2 (3 times the size of the UK) has been destroyed. There are lots of causes….. 70% of deforestation was caused by cattle ranching 25% was caused by agriculture and farming 3% was lost to logging 2% was lost to other activities such as mineral extraction (gold mining), road building and dam building Population growth and migration to the area is also putting pressure on the Amazon rainforest, especially as the Brazilian Government offers land in the rainforest to poor people to reduce overcrowding in cities. What are the impacts of deforestation? Environmental Impacts Economic Impacts 1) The Amazon stores around 100 billion tonnes of carbon. If there are fewer trees and plants, 1) Countries that were very poor due to deforestation, then less carbon dioxide 2) Farming makes lots of money for Brazil. In 2008, is removed from the atmosphere. Brazil made $7 billion from trading cattle In this way deforestation contributes to global 3) As Brazil has expanding its agriculture into the warming and therefore climate change. Amazon, it is now the 5th biggest exporter of food in the world. 2) Brazil is losing 55 million tons of topsoil every year because of soil erosion caused by farming 4) In the Amazon, 3,000 people are employed in the mining industry. 3) In the Amazon, 1 million species are threatened as human activity expands deeper into the 5) Logging accounts for 7% of Brazil’s GDP (wealth). rainforest. Brazil accounts for 3% of all forestry produce. 6) The money created from these enterprises From August 2018 to July 2019, the Amazon allows a country to generate foreign income, which lost over 3,800 sq. miles of forest — an area can then be used to pay off debts or be invested in equivalent to over 1.8 million football fields — further development projects which signified the highest rate of deforestation in the decade GCSE Practice Question: ‘Explain how deforestation in tropical rainforests creates economic advantages but at a cost to the environment (6 marks) 23  Tropical Rainforests – Sustainable Management Why is it important we manage the rainforests? TRF store ¼ of the world’s carbon TRF provide fruit, spices and rubber that are sold worldwide The TRF is used as a tourist site and generates jobs and income More than 20% of the world’s oxygen supply is provided by the TRF TRF is rich in biodiversity with 6 million different species Around 25% of all medicines come from TRF plants TRF are home to 350 million people around the tropics. They are essential for shelter, health and food as well as being an intrinsic part of their cultures and traditions. ¼ of the world’s fresh water is stored in the Amazon basin. TRF are part of a global irrigation system –that helps form clouds and distribute fresh water around the planet How can Tropical Rainforests be managed sustainably? Selective Logging Afforestation Only some trees (eg just the older ones) This is when new trees are planted to are cut down replace the ones that are cut down. Selective logging of mature trees ensures This means there will be trees for people that the rainforest canopy is preserved. to use in the future This method allows the forest to recover It’s important that the same types of because the younger trees gain more tree are planted that were cut down, so space and sunlight to grow. Planned and the variety of trees is kept for future. controlled logging ensures that for every In some countries, laws make logging tree logged another is planted. companies replant when they clear an area Ecotourism Debt Reduction Ecotourism is environmentally friendly The rainforests are often found in poorer tourism where…… countries that want to exploit them. Debt the people involved seek to protect the reduction or conservation swaps offer an environment as much as possible alternative to poorer countries to the reckless there is education of the visitor exploitation of their natural wealth. some of the profits go back into conserving the rainforest environment These swaps basically see poorer countries the tourism is small scale with low visitor have portions of their debts wiped out or paid densities for by richer nations or charities of richer local people are employed and involved nations in exchange for promising to protect or CONSERVE large parts of their forests. International Agreements There are also international agreements on the uses of tropical hardwoods and logging. The International Tropical Timber Agreement was set up in 2006 to "promote the sustainable management of tropical timber producing forests". 71 countries have signed up to the agreement sponsored by the United Nations. 24  Hot Deserts Deserts cover about one third of the Earth's land area. A desert is a very harsh environment with very little rain and extreme temperatures. An example of a desert is the Sahara, here the weather is very hot and dry, with less than 250mm of rain per year. There is not much life in the deserts as animals find it hard to survive. Where are deserts located? The world’s hot deserts are found in subtropical areas between 20 and 30 north and south of the Equator. The Tropic of Cancer or the Tropic of Capricorn passes through most of the world’s hot desert regions. Deserts can be found in 5 of the world’s 7 continents. Why are deserts NOT located at the equator? The sun’s rays are more concentrated at the equator, so it is the hottest part of the earth. This intense heat warms the land, the air and the sea and causes water to evaporate into the air. This very warm, moist air then rises. Once the warm air rises it cools and the water turns back into rain, creating clouds. This means that although it is hot, there is lots of at the equator (hence rainforests are located here, NOT DESERTS!) 1. Equator is VERY hot 2. Warm air rises 3. By the time it reaches 30N or South the air has lost any moisture 4. It starts to cool down as it gets further away from the equator and the cool, dry air sinks back down. 5. As it gets closer to the EQUATOR again it heats back up and the process repeats What is the soil like in a desert? It is usually shallow with a coarse, gravelly texture. There’s hardly any leaf fall so the soil isn’t very fertile. Lack of rainfall and plant material mean the soil is often dry 25  Hot Deserts – Plant and Animal Adaptations Hot deserts have distinct characteristics that allow certain species to thrive in such an extreme environment. Plants and animals have developed adaptations which allow them to survive in hot and dry conditions. Plant Adaptations Small leaves - these ensure that less water is lost from the plant by transpiration because the leaf has a smaller surface area. Tap roots - these are long roots (7-10 metres long) that reach deep under the ground to access water supplies. The tap roots are much longer and bigger than the plant which is visible at the surface. Spines - some plants have spines instead of leaves, eg cactuses. Spines lose less water than leaves so are very efficient in a hot climate. Spines also prevent animals from eating the plant. Waxy skin - some leaves have a thick, waxy skin on their surface. This reduces water loss by transpiration. Water storage - some plants, known as succulents, store water in their stems, leaves, roots or even fruits. Plants which store water in their leaves and stems also have a thick waxy skin so that they lose less water by transpiration. How have animals adapted? How have camels adapted? long eye lashes, hairy ears and closing nostrils help to keep out sand thick eyebrows which stand out and shade eyes from the sun wide feet so they don't sink in the sand they can go without water for over a week because they can drink gallons in one go they can go months without food - they store fat in their humps body temperature can change to avoid losing water through sweating they are well camouflaged thick fur helps to keep them warm at night Some animals are nocturnal so they can stay cool at night, such as fennec foxes. These foxes also have large ears to which provide a large surface area to lose heat as well as to hear prey. Their feet are also covered in fur to insulate. Fennec Fox 26  Hot Deserts – Thar Desert Case Study The Thar is the most densely populated deserts in the world- it stretches across northwest India and into Pakistan. It covers around 200 000km2. Opportunities for economic development in the Thar Desert: There are lots of development opportunities in the Thar Desert 1) Mineral extraction- phosphorus for fertilisers, gypsum for cement and plaster and kaolin used in making paper. Provides jobs for local people. 2) Energy- large oil field near Barmer, huge solar power potential due to long hours of sunshine, India’s third largest wind farm at Jaisalmer 3) Farming- Mostly subsistence farming involving grazing animals and growing crops, the Indira Gandhi Canal enables commercial farming to thrive as it provides irrigation 4) Tourism- several companies offer desert safaris and visits to Jaisalmer, ecotourism is popular with small groups taking camel treks into the wilderness areas and oasis. …but there are also challenges to development 1) Most people live in small fertile areas, where water from a spring or well is used to irrigate the ground so that crops, e.g. maize can be grown. Others are nomadic, constantly searching for fresh grazing for their herds of goats, sheep and camels. 2) Development in the Thar Deserts is challenging- trying to locate and exploit resources in the hot, dry, remote desert: Extreme Temperatures Inaccessibility 1) Due to the lack of cloud cover, daily temperatures can range from over 40°C during 1) The Thar Desert is huge- people and the day to below freezing at night Exposure to materials have to travel long distances- often high temperatures can cause illness or death, and by air, which is expensive. healthcare may be a long distance away. 2) Limited road network due to vast distances 2) The hot season is often too hot for tourists so and high maintenance costs. employment in the tourism industry can be 3) Sand can blow onto roads and tarmac can seasonal. melt in the extreme heat. Many resort to 3) Work outside is very hard, especially for farmers traditional camels. who have to work during the day 4) It’s difficult to provide services, e.g. medical 4) High temperatures lead to high rates of care, to remote regions making it hard for evaporation and water shortages them to develop. Water Supply 1) Thar Desert has very low annual rainfall with high rates of evaporation, a secure water supply is crucial for economic development. 2) Traditional water is stored in natural ponds called tobas, used by farmers in remote areas. 3) Most rivers are erratic but settlements tend to cluster along their edges. Climate change could make river flow less reliable. 4) Indira Gandhi Canal has transformed the desert, providing drinking water and irrigation. 27  Hot Deserts – Desertification Desertification is the segregation of land so that is becomes more desert like – it becomes drier and less productive. A third of the world’s land surface is at risk of desertification, particularly at the margins of current deserts. The most famous area at risk from desertification is the Sahel in Africa, just below the Sahara Desert. Causes of desertification Climate Change Human Activities 5) Rainfall – climate change is 1) Removal of fuel wood – many people in arid expected to reduce rainfall in (dry) areas rely on wood for fuel or cooking. areas that are already dry. Less Removal leaves the soil exposed = erosion rain = less water for plant growth. 2) Overgrazing – too many cattle eat the plants If the plants die, the soil is easily faster than they can re-grow. This leads to soil eroded. erosion as no plants left to bind the soil. 6) Temperatures – Global 3) Over-cultivation – if crops are planted in the temperatures are expected to same area continually, all the nutrients in the increase. Higher temperatures soil get used up. This means that plants can no mean that more water evaporates longer grow in this areas. from the land and from plants. 4) Population Growth – This puts pressure on the This makes soils drier and means land, leading to move deforestation, more that pants die (so their roots no over-grazing and more over-cultivation. longer bind the soil together) Increased risk of flooding Effects Effects of desertification Crop Failure Famine Salinization occurs when the water in soils Increased Soil Erosion evaporates in high temperatures, drawing salts Lack of Vegetation for grazing from the soil to the surface. These salts are Loss of nutrients in the soil toxic to many plants and make the land Population decline as people move away unusable. This has consequences such as low Reduced biodiversity yields, poor profits and even starvation. Salinization caused by over-irrigation. Salinization 28  Solutions to desertification Afforestation Planting more trees - the roots of trees hold the soil together and help to reduce soil erosion from wind and rain. Growing trees in amongst crops (agroforestry) helps protect the soil, as well as providing shade for the crops Water Management Water management - water can be stored in earth dams in the wet season and used to irrigate crops during the dry season. This is an example of using appropriate technology to manage water supplies in the desert environment. You can also grow crops that don’t need much water (olives) which can reduce water use. Soil Management Improving the quality of the soil - this can be managed by encouraging people to reduce the number of grazing animals they have and grow crops instead. The animal manure can be used to fertilise the crops grown. Growing crops in this way can improve the quality of the soil as it is held together by the roots of plants and protected from erosion. This type of farming is more sustainable. Rotating crops that use different nutrients from the soil means the same nutrients don’t keep getting used Appropriate technology e.g. Stone Lines (Bunds) Local farmers are encourages to use the bunds to prevent soil erosion. Magic stones (or bunds) are circles or walls of stones placed on the ground to hold water on the soil rather than letting it run quickly over the surface. The picture to the right shows a Bund Wall. Solar cookers can also be used, these use the sun’s energy to cook food rather than fuel wood and are cheap and easy to use. GCSE Practice Question: ‘Assess the importance of management strategies used to reduce GCSE Practice the risk Question: ‘Explain of environmental damagehow vegetation caused in hot deserts adapts by desertification.’ to the climate. (4) (9 Marks) GCSE Practice Question: ‘Using a case study, to what extent have opportunities for economic activity been developed in your chosen environment?’ (9 marks) GCSE Practice Question: ‘To what extent is the Thar Desert at risk from human activity? (9 marks) 29  Paper 1 Section Ca COASTS – Why do our coastlines change? Coastal erosion is of great concern to many people as it can causes disruption to everyday life and services. Many people have consequently lost their homes and businesses to coastal erosion. But erosion is also responsible for some of the most spectacular coastal features too. How do our coastlines erode material? Hydraulic Action This is the power of the waves as they smash onto the cliff. The trapped air is forced into cracks and holes in the rocks. Eventually forcing the rock to break apart. Abrasion Fragments of rock, pebbles and sand are picked up by the waves and hurled at the base of the cliffs. They act like sandpaper, eroding the base of the cliff. Attrition This is when rock fragments that are moving about underneath the water rub against one another knocking fragments off. This processes happens continually and eventually wears the rocks down. Solution Rocks can also be eroded through chemical action. This is when sea water dissolves certain types of rocks. In the UK, chalk and limestone cliffs are prone to this type of erosion. How do our coastlines transport material? Material that’s been eroded is moved around the coast and deposited by waves Suspension Solution Particles carried (suspended) This is rock being transported as dissolved within the water. chemicals, often from chalk and limestone cliffs. Traction Saltation This is when large pebbles are rolled along Turbulence and currents lift up pebbles the seabed by the currents. which then bounce along the sea bed. 30  COASTS – Why are waves important? Wind blowing over the ocean creates friction with the water surface causing ripples to form. The longer the waves travel for, the larger and more organised they become. The distance travelled is called the fetch! The stretch of the coastline that faces the waves is known as the aspect. Constructive Waves These are low waves the surge up the beach and spill with a powerful swash. The carry large amounts of sand and pebbles, and construct the beach. They have travelled a very long way (Large fetch). Destructive Waves These are formed by local storms close to the coastline. They take beach material away, therefore they can erode the beach. They are steep, plunging waves, close together and have a stronger backwash than swash. This is why they are effective at removing sand and pebbles from the beach. Mass movement Rockfalls 1) Mass movement is the shifting of Bits of rock fall rocks and loose material down a off the cliff slope (cliff). It happens when the face, usually force of gravity acting on a slope due to freeze- it greater than the force thaw weathering. supporting it. 2) Mass movements cause coasts to Landslides rapidly retreat 3) They’re more likely to happen Slumps Large when the material is full of water Saturated soil blocks of – it acts as a lubricant, and rock slide slumps down a makes the material heavier downhill. curved 4) You need to know about 3 types surface... ….. 31  COASTS – Landforms caused by erosion Wave Cut Platform The waves cause the most erosion at the foot of a cliff This forms a wave-cut notch, which is enlarged as erosion continues The rock above the notch becomes unstable and eventually collapses The collapsed material is washed away and a new wave-cut notch starts to form Repeated collapsing results in the cliff retreating Headlands & Bays A wave-cut platform is the platform Bands of soft rock such as clay and sand are that’s left behind as the cliff weaker therefore they can be eroded quickly. retreats This process forms bays. A bay is an inlet of the sea where the land curves inwards, usually with a beach. Hard rock such as chalk is more resistant to the processes of erosion. When the softer rock is eroded inwards, the hard rock sticks out into the sea, forming a headland. Headlands and Bays form where there are alternating bands of resistant and less resistant rock along a coastline. Caves, Arches & Stacks Cracks are widened in the headland through the erosional processes of hydraulic action and abrasion. As the waves continue to grind away at the crack, it begins to open up to form a cave. The cave becomes larger and eventually breaks through the headland to form an arch. Caves, arches, stacks and stumps are The base of the arch continually becomes wider erosional features that are commonly through further erosion, until its roof becomes too found on a headland. heavy and collapses into the sea. This leaves a stack (an isolated column of rock). GCSE Practice Question: ‘Explain the formation of a wave-cut The stack is undercut at the base until it collapses platform’. [4 marks] to form a stump. 32  COASTS – Landforms caused by Transportation & Deposition Longshore Drift Material is transported along a coast by a process called Longshore Drift: 1) Waves follow the direction of the prevailing wind 2) They usually hit the coast at an oblique angle (any angle that isn’t a right angle) 3) The swash carries material up the beach, in the same direction as the waves Deposition 4) The backwash carries material Deposition is when material being carried by the down the beach at right angles, water is dropped on the coast. It occurs when the back toward the sea. water doesn’t have enough energy to carry the 5) Over time, material zig-zags along sediment. Coasts are built up when the amount of the coast. deposition is greater than erosion. Spits, bars & Tombolo’s A spit is an extended stretch of sand or shingle jutting out into the sea from the land. Spits occur when there is a change in the shape of the landscape or there is a river mouth. This is how spits are formed: Sediment is carried by longshore drift. When there is a change in the shape of the Spit coastline, deposition occurs. A long thin ridge of material is deposited. This is the spit. A hooked end can form if there is a change in Bar wind direction. Waves cannot get past a spit, therefore the water behind a spit is very sheltered. Silts are deposited here to form salt marshes or mudflats. Bar: A bar is formed as above, with the difference being the spit joins across two headlands Tombolo: When the spit forms an island 33  Beaches Beaches are made up from eroded material that has been transported from elsewhere and then deposited by the sea. For this to occur, waves must have limited energy, so beaches often form in sheltered areas like bays. Constructive waves build up beaches as they have a strong swash and a weak backwash. Sandy beaches are usually found in bays where the water is shallow and the waves have less energy. Pebble beaches often form where cliffs are being eroded, and where there are higher energy waves. Sand Dunes Sand dunes are formed when sand deposited by longshore drift is moved up the beach by the wind. Obstacles cause the wind speed to decrease so sand is deposited. This sand is colonised by plants and grasses. The vegetation stabilises the sand and encourages more sand to accumulate there, forming small dunes called embryo dunes Over time, the oldest dunes migrate inland as newer embryo dunes are formed. These mature dunes can grow up to 10m tall. GCSE Practice Question: ‘Explain how the processes of deposition lead to the formation of distinctive landforms. [6 marks] COASTS – Weathering Freeze-Thaw Weathering Freeze-thaw weathering occurs when rocks are porous (contain holes) or permeable (allow water to pass through). Water enters cracks in the rock. When temperatures drop, the water freezes and expands causing the crack to widen. The ice melts and water makes its way Biological Weathering deeper into the cracks. The process repeats itself until the rock Plants and animals can also have an effect splits entirely. on rocks. Roots burrow down, weakening the structure of the rock until it breaks away. Chemical Weathering Plant roots can get into small cracks in the rock. Rainwater and seawater can be a weak acid. If As the roots grow, the cracks become a coastline is made up of rocks such as larger. limestone or chalk, over time they can become This causes small pieces of rock to dissolved by the acid in the water. break away. 34  COASTS – UK Coast Example – The Dorset Coast The Dorset Coast is made from bands of hard rock (limestone and chalk) and soft rock (clay). The rocks have been eroded at different rates giving headland and bays and lots of other coastal features. Durdle Door is a great example of an Lulworth Cove is a small bay formed after a gap arch. Erosion by the waves opened up was eroded through a band of limestone. Behind a crack in the limestone headland, the limestone is a band of clay, which has been which became a cave and then eroded away to form the bay. developed into an arch Chesil Beach is a tombolo (a Swanage Bay is two bays with beaches called Swanage type of spit) formed by Bay and Studland Bay. They’re areas of softer rock. In longshore drift. It joins the Isle between them is called a headland called The Foreland of Portland to the mainland. which is made of harder rock (Chalk). The end of the Behind Chesil Beach is a shallow headland has been eroded to become a stack called Old lagoon called the Fleet Lagoon. Harry and a stump called Old Harry’s wife. Lulworth Cove Chesil Beach Old Harry GCSE Practice Question: Explain the formation of a spit. (4 marks) 35 Do you agree?  COASTS – Coastal Management Strategies Hard Engineering Soft Engineering Hard engineering management involves using Soft engineering does not involve artificial structures, whereas soft engineering building artificial structures, but management is a more sustainable and natural takes a more sustainable and natural approach to manage coastal erosion. approach to managing the coast. Defence What is it Benefits Costs SEA WALL A wall is made out of It prevents erosion of It creates a strong hard material like the coast. It also acts as backwash, which erodes concrete that reflects a barrier to prevent under the wall. Sea walls wave energy back to flooding are expensive and ugly sea GABIONS A wall of wire cages The gabions absorb wave They’re ugly and the filled with rocks usually energy and reduce wire cages erode over built at the foot of erosion. They’re cheap & time cliffs easy ROCK ARMOUR Boulders that are piled The boulders absorb Boulders can be moved up along the coast. wave energy and reduce around and they are erosion and flooding. It hard to get into place as is cheap are lacks and heavy GROYNES Wooden fences that They create wider They starve beaches of are built at right angles beaches which slow sediment further down to the coast. They trap waves. This gives greater the coastline. These material transported protection from flooding then have less by longshore drift. & erosion. protection against erosion. BEACH Sand and shingle added It creates wider beaches It is very expensive and REPLENISHMENT to the beach. which slow the waves and needs to be constantly protects against flooding repeated and erosion SAND DUNE Creating or restoring Sand dunes provide a The protection is limited REGENERATION sand dunes. barrier between the land to a small area. It is and the sea. Wave very expensive. energy is absorbed which prevents flooding. It is cheap. Managed Retreat 1) Managed Retreat involves removing coastal defences and allowing the sea bed to flood behind. 2) Over time the land will become marshland, which then protects the land further behind from flooding and erosion 3) It is cheap and easy and doesn’t need maintaining. The marshland also creates new habitats. 4) It can cause conflict to those who lose land to the retreat, often farmers. 36  COASTS – Coastal Management Case Study: LYME REGIS Location Issues in Lyme Regis Small coastland The town is built on unstable cliffs. The town is built on a layer of strong town in SW limestone which is very solid. On top of that layer there are slippery muds, England. In the clays and sands which slide over the limestone layer to form the landslides. heart of a The sea erodes the cliffs at the bottom of the landslide, causing it to heritage become unstable and slip even further. coastline called Houses, buildings and roads become damaged as the land slips towards the the Jurassic sea. Coast. Why does Lyme Regis need protecting? GCSE Practice Question: The local economy depends on tourism as its main ‘Coastal management source of income schemes are effective in 37,500 people are employed in the tourist sector in the protecting the coastline from physical processes.’ Do you town agree? Use an example in The area generates £800 million per year from tourism your response (9) The town hosts many festivals, including an annual fossil festival. Do you agree? Management of the Coastline The Lyme Regis Environmental Improvement Scheme was set up in the early 1990s to provide long-term coastal protection and reduce the threat of landslips Phase 1: New sea wall and promenade constructed to the east of the River Lim. In the winter of 2003 a £1.4 million emergency project was completed to stabilise the cliffs 1000 steel pins were used to hold rocks together. Phase 2: Creation of a wide sandy beach (nourishment) to absorb wave energy and increase us of the shore: the beach was nourished with 75,000 tonnes of shingle dredged from the Channel Phase 3: Initial plan to prevent landslips and coastal erosion to the west of the Cobb were shelved. It was decided to leave this stretch of the coast alone as the costs outweighed the benefits. Phase 4: The final phase focused on the coast east of the town. It cost £20 million and involved constructing a new 390m sea wall in front of the existing wall. Advantages Diadvantages The new beaches have increased visitor The scheme was very expensive, over £30 numbers and sea front businesses are million thriving The beach needs to be replenished every 3 The new defences have stoop up to recent years. stormy winters The sea wall will need replacing in 30 years The harbour is now better protected, Locals complained about construction noise benefiting boat owners and fishermen. Sea defences may speed up erosion Residents can now get house insurance further down the coastline 37  Paper 1 Section Cb RIVERS The path of a river as it flows downhill is called its course Long Profile Rivers have an upper course, a middle course and a lower course Rivers form channels and valleys as they flow downhill They erode the landscape, transport material and then deposit material The shape of the river changes along the river depending on whether erosion or deposition is taking place A rivers long profile of a river shows how the gradient (steepness) changes over time,