| what is a fungicide | fungal diseases can be controlled by chemicals |
| what is biological control | an alternative way to control pests and diseases is to find natural predators that can solve the problem, if the predators can be bred in large enough quantities they are introduced to a crop, they can feed off the pest and control the infestation |
| advantages of biological control | no chemical residues left in the crop, when the pest has been controlled the lack of food will also control the predator numbers, there is no need to wear protective gear when applying |
| disadvantages of biological control | not as instant as chemical control, the predator might not stay on the crop and leave the pest, the predator may escape into the local countryside and impact the food web |
| advantages to using machines | Larger areas can be cultivated easily by one person which reduces the labour costs, the machine’s engine can take still work when there is more water in the soil (when it is heavier) |
| process of selective breeding | - identify which characteristics of the species are important
- choose parents that exhibit these characteristics
- raise the offspring from these parents
- select the best offspring that show the desired characteristics
- repeat the process |
| reasons for genetically modifying plants | - disease and pest resistance
- nutritional value
- higher yields
- less use of pesticides |
| greenhouse | a building made of glass or similar transparent material that is used to manage the environment for plant growth. |
| hydroponics | growing plants without soil, with the nutrients the plant needs to be dissolved in water |
| advantages of hydroponics | - easy to harvest
- plants are given exactly the nutrients they need in the irrigation water
- water is recycled, so used efficiently |
| disadvantages of hydroponics | - it is expensive to set up
- only suitable for small production areas
- disease, if present, is spread to all plants through water |
| overuse of insecticides and herbicides | can cause the plant to become resistant, can kill beneficial insects which can impact wider food webs, leaching of insecticides and herbicides into rivers and lakes |
| overuse of fertilizers | excess can be leached out of the soil and drain into waterways, can cause excessive growth where the plant can't support itself, can affect osmosis |
| mismanagement of irrigation | waterlogged plants prevent plant roots getting sufficient oxygen to respire, can become waterlogged and salts in soil can move through to the top and when it evaporated only the salts are left which can means osmosis isn't effective and water supplies may also become unsuitable for drinking |
| overproduction and waste | - storage space is wasted storing crops that take longer to sell – costly to provide
- transport costs wasted when taking crops to market that do not get sold
- waste of labour in growing and harvesting a crop if it cannot be sold |
| cash crops replacing food crops | local farming for local food consumption is pushed onto poor land and soils producing poor crop yields and low-quality food, thereby affecting the health of the people |
| causes of soil erosion | - removal of natural vegetation
- over cultivation
- overgrazing
- water erosion
- wind erosion |
| removal of natural vegetation | Removing plant roots weakens soil (from over cultivation and overgrazing), making it vulnerable to rainfall. Flash floods erode and carry away topsoil. Tree roots slow water and trap soil, preventing erosion. Without vegetation, run-off is unchecked. Rainforest areas cleared for cultivation suffer severe erosion, forcing growers to relocate frequently |
| over cultivating | damages soil structure - regularly cultivated soils lose structure as ploughing breaks larger clumps into smaller particles. While this aids sowing and seedling development short term, the mechanical breakdown makes the soil more prone to erosion. |
| over grazing | pressure on grazing land can lead to overgrazing, reducing vegetation to ground level. Hard grazing weakens plants by limiting photosynthesis, causing them to die. Without vegetation, there are no roots to hold the soil together, increasing erosion and potentially forcing livestock relocation |
| water erosion | water is a major cause of soil erosion. Heavy rain dislodges soil particles, and run off carries away unabsorbed soil. Compacted soil reduces water infiltration. Gully erosion occurs when fast-moving water erodes soil, forming deep crevices, initially caused by rainwater run off |
| wind erosion | removing vegetation makes soil more prone to wind erosion. Vegetation may be cleared for space, excessive grazing, increased crop development, or removing hedges and boundaries to accommodate large machinery like tractors |
| impacts of soil erosion | loss of habitats, desertification, silting of rivers, displacement of people, malnutrition and famine |
| loss of habitats | loss of soil also means a loss of habitat for organisms to live in (either the fertile topsoil or the vegetation), fewer or no plants means no shelter for animals or food |
| desertification | remaining subsoil cannot support the growth of plants and impacts on both the growing of crops and the growing of grass to feed livestock |
| silting of rivers | causes silting of waterways, the build-up of sediment due to more topsoil being washed into the rivers and the flow of the rivers slow down as they get shallower |
| displacement of people | with the decline of agriculture due to desertification, local people may be forced to move, to make a living or feed their families |
| famine and malnutrition | the time delay between planting new crops after migrating and harvesting the food means that there is not a reliable source of food and a real risk of famine |
| how to reduce soil erosion | terracing, contour ploughing, bunds, wind breaks, maintaining vegetation cover, addition of organic matter to improve soil structure, planting trees, mixed cropping, intercropping and crop rotation |
| terracing | a sloped hillside is carved into steplike shapes, allowing some of the water to be held back and preventing lots of water flowing down the slope and destroying soil. the majority of the water is held back |
| contour ploughing | when the ridges and troughs from the ploughing run along the contours of the land (around the hillside) rather than up and down. Each plough troughs hold water back and prevents large amounts of water rushing down the slope and carrying topsoil with it. |
| bunds | artificial banks of soil on the edge of a growing space designed to hold back water and preventing soil erosion from run-off, especially useful for crops such as rice that need to be submerged or require moist soils |
| wind breaks | a wind barrier, either made from living vegetation or an artificial screen with gaps, helps reduce wind erosion. Solid walls can increase wind speed and create eddy currents that lift soil particles, while natural vegetation allows some wind through but lowers wind speed, reducing erosion. |
| maintaining vegetation cover | maintaining vegetation cover helps reduce soil erosion by preventing wind from carrying away exposed soil. Farmers can plant a cover crop, like clover, immediately after harvesting the main crop to protect the soil. Clover also enriches the soil with nitrogen when ploughed in before the next planting. |
| addition of organic matter to improve soil structure | Organic matter like manure and compost adds weight and structure to the soil, reducing erosion by retaining water and preventing it from drying out. It also supports strong root growth, which helps keep soil in place. |
| tree planting | a row of trees can form a windbreak to protect other crops, tree leaves fall to the ground and therefore add to the organic matter content of the soil |
| mixed cropping | the growing of more than one type of plant in the same area, each plant may have different characteristics that reduce soil erosion |
| intercropping | rows of different crops are grown between the established rows of the main crop, the quicker growing plants can be harvested for profit while the slower main crop is maturing |
| crop rotation | Planting different crops each year in the same plot of land helps reduce pests, improves the quality of the soil, and utilises the different nutrients more effectively, they use the soil in different ways and therefore reduces soil damage |
| strategies for sustainable agriculture | organic fertiliser, managed grazing, crop rotation, use of pest resistant and drought resistant varieties of crops, trickle drip irrigation, rainwater harvesting |
| how organic fertilizers are sustainable | release their nutrients slowly reducing eutrophication, don't require manufacturing energy, improve soil structure |
| how managed grazing is sustainable | prevent overgrazing, different fields are fertilised by animal waste and not one field has too many nutrients, maintain good drainage as animal hooves don't reduce soil compaction |
| how crop rotation is sustainable | less likely to be an oversupply, fewer risks of pests and diseases, natural fertiliser for the soil if animals are included |
| how use of pest resistant and drought resistant varieties of crops is sustainable | reduced pesticide use, reduced need of irrigation, shorting cropping cycles allowing two or more crops a year |
| how trickle drip irrigation systems are sustainable | minimised the amount of water used, targeted delivery of water to the plants, only use the system when the plants need water |
| rainwater harvesting | the collection of rainwater for example from the roofs of buildings and storage in a tank or reservoir for later use |
| how rainwater harvesting is sustainable | make use of a readily available natural resource |
| particle size of sand vs. silt vs. clay | 2.0-0.02mm, 0.02-0.002mm, <0.002mm |
| organic content of sandy vs. clay soil | less than 1%, clays from 4% - 5%+ |
| pH of sandy vs. clay soil | lower pH, higher pH |
| air content of sandy vs. clay soil | larger air gaps allowing good transmission with high levels of oxygen and therefore a healthy root system, small air spaces that limit the amount of oxygen reaching the roots, this in turn limits respiration and the amount of root growth |
| water content of sandy vs. clay soil | sandy soils hold and contain less water as there is less surface area, clay soil has far more particles and therefore a larger surface area for water to cling to |
| drainage of sandy vs. clay soil | free draining because of large space in particles, not free draining due to particles packed together |
| ease of cultivation of sandy vs. clay soil | easier to cultivate because particles stick together, hard to cultivate |
| name the 6 resource potentials of the ocean | food, chemicals and building materials, energy (wave and tidal), tourism, transport, drinking water |
| food | ocean provides for fish and other edible sea animals, world fishery yields are about 90 million tonnes in a year with over 80 million tonnes of that coming from the sea |
| chemicals and building materials | oceans cover 71% of the Earth's surface, with 3.5% of seawater composed of dissolved substances like salt, magnesium, gold, and titanium. Mining for sand and gravel boosts these mineral resources. Oil is a well-known chemical derived from the sea, with thousands of offshore drilling rigs worldwide. |
| energy (wave and tidal) | there is an enormous amount of energy in the waves that break on the shores all around the world. If this energy could be harvested, it would be double the present world energy production. |
| tourism | the seaside has been a major tourist attraction for centuries. People in MEDCs of the world are attracted to marine sites of great natural beauty. Also, activities like whale watching while contributes 2 billion USD to the world economy. |
| transport | ships are an important way of transporting people and goods, today shipping is less important for moving people because of avitation (planes) |
| drinking water | with the world’s population now exceeding 8 billion many essential commodities like water are harder to obtain. We can harvest water from the ocean using desalination plants. |
| distribution of warm and cold ocean currents | in the Southern Hemisphere, they are usually anti-clockwise, cold currents are near the north and south poles, warm currents are near the equator and the tropics |
| distribution of major fish populations | they are found in shallow continental shelves, as there is a large amount of oxygen & phytoplankton, phytoplankton are a part of the food web, so the fish rely on the phytoplankton |
| why not all areas with continental shelves have significant fisheries | phytoplankton need light, CO2, and water and not all areas have those |
| El Niño Southern Oscillation | the change in the prevailing winds that lead to a change in the pattern of the current in the oceans of the South Pacific |
| effect of El Niño on the fisheries | fewer fish are caught and if fishing continues at its usual amount, over-fishing can occur, and the fishery can collapse, phytoplankton do not grow well, so there is less food for the fish. During El Niño, the reduction in fish-meal affects the fish farming industry of countries |
| effect of El Niño on Peru | the normal trade wind direction from east to west changes every 8 – 12 years, allowing warm nutrient-poor water to flow from the west towards the coast of Peru. This stops the upwelling of the cold, nutrient-rich water that supports the anchovies fishing |
| causes of overfishing | demand for fish as food due to increasing population, economic gain, creation of huge nets that scoop up everything in an area |
| impact of overfishing on marine fish species | reduced catching - means the loss of jobs and a reduction in the food supply, the size of fish gets smaller - increasing the demand, increase the fishing efforts, reduction in marine biodiversity - disrupting the food chain |
| farming marine species | increased demand for fish - above production capacity of oceans
overexploitation of fisheries - decline in wild fish population
so fish a farmed in controlled environments |
| aquaculture | farming freshwater fish |
| mariculture | aquaculture practised in marine environments |
| advantages of marine farming | reduces the pressure on the wild population which allows them to increase, production is constant, no bycatch, no erosion of the seabed |
| disadvantages of marine farming | more prone to diseases, less likely to be successful due to pollution from waste |
| sustainable strategies for reducing the harvesting of marine species | net type, mesh size and shape, quotas, closed seasons, protected areas, international agreements, conservation laws |
| net type | certain net types are banned from use |
| mesh size and shape | small mesh size results in bycatch and the square mesh shape instead of diamond allows smaller fish to escape, if mesh size is too small it will catch juveniles |
| quotas | a good way of managing fisheries by setting limits on how many organisms can be caught per time limit which allows them to reproduce |
| closed seasons | government can close fisheries down during parts of the year this is commonly done in the breeding season |
| protected areas | areas can be protected by preventing fishing in those areas often where they breed |
| international agreements | rules all countries abide by in ocean territories |
| conservation laws | laws enforced by governing territories in zones where fish can’t be caught, etc |
| continents and oceans | continents and oceans |
| nitrogen | 78%, needed for plant growth (making proteins) |
| oxygen | 21%, produced by photosynthesis and used in respiration |
| water vapour | 0.2 – 0.4%, source of all precipitation, acts as a natural greenhouse gas, vital to life on Earth. |
| carbon dioxide | 0.03%, used by plants in photosynthesis which as a primary producer to support other life forms, is a greenhouse gas |
| ozone | 0.00006%, absorbs ultraviolet radiation thereby protecting life on Earth from the effects of too much of the harmful radiation |
| argon | >0.93, can create an inert atmosphere that protects materials from reacting with oxygen or other gases |
| troposphere | temperature decreases with height (averaging 6.4 degrees C km -1) The top of the layer is marked by tropopause, where temperature remains constant. The boundary occurs at a height of 8km and at the poles and 17km in the tropics and marks the upper limit to the earth weather and climate. |
| stratosphere | this layer extends to nearly 50km above the earth surface, pressure continues to fall, temperatures increase steadily with height, called temperature invasion and absorbs the UV radiation, the upper limit is determined by the stratopause |
| mesosphere | 50-80km in height, pressure decreases and temperature falls to below -80 C as there is no water vapour dust or ozone to absorb the incoming short-wave radiation, the mesopause marks the upper limit of this layer. |
| thermosphere | 80-1000 km in height and temperatures rise rapidly to as high as 1500 C because of the absorption of UV radiation, the thermopause marks the upper limit of this layer |
| atmosphere | atmosphere |
| causes of atmospheric pollution | smog, acid rain, ozone layer depletion, enhanced greenhouse effect |
| natural greenhouse effect | the natural greenhouse effect keeps the Earth's surface about 33°C warmer, enabling life in a cold universe, water vapour, carbon dioxide, dust, and ozone trap heat in the atmosphere, preventing too much harmful short-wave radiation from reaching the surface and stopping all long-wave radiation from escaping into space. |
| stages of the natural greenhouse effect | 1. About 50% of the sun's incoming short-wave radiation is absorbed by the Earth's surface, while 20% is absorbed by the atmosphere and 30% is reflected into space by clouds and the Earth's surface.
2. The absorbed short-wave radiation warms the Earth's surface.
3. The warm Earth emits long-wave infra-red radiation back into the atmosphere.
4. Greenhouse gases absorb some of this outgoing long-wave radiation, heating the atmosphere or reflecting it back to the Earth's surface. |
| short wave radiation | incoming or short-wave solar radiation, visible light and ultraviolet radiation are commonly called short wave radiation |
| long wave radiation | outgoing or terrestrial radiation, as the earth produces very little visible light or ultraviolet radiation, all radiation from the earth is infra-red |
| processes involved in the natural greenhouse effect | processes involved in the natural greenhouse effect |
| the greenhouse gases | the greenhouse gases |
| smog | burning fossil fuels provide particles such as unburnt hydrocarbons that act as condensation nuclei for fog to form. VOC's from industrial processes also provide particulate matter that act as condensation nuclei for fog to form. Particulate matter associated with industrial and urban areas is more frequent during winter due to heating and the incomplete combustion of fuel forming particulate matter |
| photochemical smog | when sunlight causes chemical reactions to occur on certain air pollutants that convert them into harmful ground-level and tropospheric ozone |
| temperature inversion | can trap warm air and smog in a valley under high pressure. This can concentrate the smog enough to block out the Sun, creating the "dustbin lid effect." |
| conditions needed for a temperature inversion to form | - high air pressure (anticyclone) which causes the upper air to sink
- calm conditions resulting from high pressure (wind will disperse smog)
- valleys surrounded by steep-sided hills, which trap the smog |
| acid rain | pH<6, caused by sulphur and nitrogen oxides from burning fossil fuels and vehicle emissions. These gases mix with atmospheric water vapour and oxygen to form weak nitric and sulphuric acids. The wind carries these acids away from their source, resulting in "wet deposition." |
| ozone layer depletion | occurs when chlorofluorocarbons (CFCs) release chlorine that breaks down stratospheric ozone, which blocks harmful ultraviolet radiation. This creates the "ozone hole," more pronounced over Antarctica in winter due to chemical reactions in the polar vortex. In summer, the ozone hole temporarily recovers as chlorine converts to other compounds. |
| enhanced greenhouse effect | caused by human activities adding greenhouse gases like carbon dioxide, water vapour, and methane to the atmosphere, leading to more heat being retained and rising global temperatures, burning of fossil fuels is the largest contributor, deforestation also increases atmospheric carbon dioxide by reducing the number of trees that absorb it |
| effects of smog on humans | irritation of eyes and throat, increasing respiratory diseases such as asthma, fine particles carried into the lungs leading to lung cancer, strokes and heart attacks, breathing difficulties |
| effects of smog on the environment | ability of plants to make and store food through photosynthesis is reduced, growth reproduction and general health of plants decline making them more prone to disease and pests |
| effects of acid rain on humans | acidification of groundwater makes water undrinkable and can cause diarrhoea and stomach upsets, limestone buildings are chemically weathered |
| effects of acid rain on the environment | aquatic and animal life in lakes is poisoned and decreases as acidity levels increase, trees affected as foliage dies, acidification of groundwater damages tree roots, crop yields decline |
| effects of ozone depletion on humans | higher levels of UV radiation causes sun burn skin cancer retina damage and cataracts |
| effects of ozone depletion on the environment | damage to vegetation melting ice sheets, glaciers and permafrost can lead to a rise in sea-levels, extra UV radiation inhibits the reproductive cycle of phytoplankton which make up the lowest layer of some food webs so this could affect the populations of other animals |
| climate change effects on human | damage to low-lying countries from flooding would be disruptive with high financial costs, forced migration as people lose their homes and farmland from rising sea-levels, warmer weather may mean farmers grow different crops and have longer growing seasons, increased droughts could lead to desertification and famine |
| climate change effects on the environment | melting of ice sheets and glaciers, sea-level rise will lead to the loss of costal land and increased erosion, more severe storms or droughts |
| reduction of carbon footprint | Individuals can reduce their carbon footprint by using public transport, flying less, conserving energy at home, and using solar power |
| reduced use of fossil fuels | governments - renewable energy programmes for electricity production to replace coal and oil-fired power stations
individuals - can use public transport and take fewer plane trips to reduce fossil fuel use |
| energy efficiency | individuals - using energy saving devices, light bulbs and turning off lights and devices when not in use, 3R's to reduce the need for mineral extraction and save energy on making new products if the old ones are not thrown away but instead reused in a variety of ways
governments - can develop and encourage the use of renewable forms of electricity production |
| carbon capture and storage | government - waste carbon dioxide from power plants, captured and transported via pipelines to storage sites |
| transport policies | governments - developing safe cycle ways, higher road user charges, making public transport cheaper |
| CFC replacement | governments - ensure processes in place for the safe disposal of items containing CFCs such as old refrigerators, regulations that ban the use of CFCs in aerosol cans and making the use of alcohol and pump action sprays mandatory |
| catalytic converters | individuals - CEO’s of car companies deciding to use catalytic converters to reduce sulphur emissions from vehicles
governments - can make it compulsory for all diesel vehicles to be fitted with particulate filters to reduce air pollution and allow the sale of only fuel low in sulphur |
| flue-gas desulphurisation | governments - the mandatory use of flue gas desulfurisation measures such as scrubbers could be made law
measures such as scrubbers can remove up to 95% of sulphur dioxide emissions and lining chimneys with lime also helps |
| taxation | governments - taxation policies can incentivise businesses and individuals to reduce pollution and invest in cleaner technologies
taxation |
| reforestation and afforestation | governments - reforestation programmes can be set up by government departments, laws can be passed to reduce air pollution emissions from industries |
| earth structure | earth structure |
| inner core | temperature of 5000-6000oC, is solid due to the intense pressure from overlying rocks and is made from iron and nickel |
| outer core | temperature of 4000-5000oC, is liquid and is make from iron and nickel |
| mantle | temperature of 1000-1200oC, is liquid and flows slowly due to the convectional currents from the core and is made of mainly silicate minerals |
| ocean crust | made from silicate and magnesium minerals, mainly made from basalt, thin at a depth of 6km, younger and can sink and is continually being renewed and destroyed |
| continental crust | made from silicate and aluminium minerals, mainly made from granite, thick at a depth of 35km but can be up to 100km under mountain ranges, lighter as 2.6g cm-3, older and cannot sink and is neither destroyed nor renewed |
| tectonic plate | is a piece of lithosphere that moves slowly, it is made of crust and upper mantle. Where the convection currents rise to the surface, the plates move away from each other and where the convection currents sink, the plates move towards each other |
| plate boundary | where two or more plates meet, the three main types of plate boundaries are constructive, destructive and conservative |
| constructive (divergent) plate boundaries | When two oceanic plates pull apart, a gap forms, and magma rises due to convection currents. This magma cools and solidifies into new basaltic crust, a process called sea floor spreading or ridge push, which can trigger small earthquakes. Over time, the crust forms mid-ocean ridges and submarine volcanoes, which may emerge as volcanic islands. These are called shield volcanoes, known for non-explosive eruptions due to low pressure. . An example is the Mid-Atlantic Ridge between the Eurasian and North American plates. If continental plates pull apart, a rift valley can form as land drops between faults. |
| destructive (convergent) plate boundaries | when two plates move towards each other, the denser oceanic plate is subducted under the lighter continental plate, forming a trench, triggering earthquakes, and creating magma that rises to form explosive composite volcanoes. Fold mountains also form. If two continental plates collide, the sediments between them are compressed and pushed up, forming fold mountains. In oceanic plate collisions, volcanic island arcs can form. |
| fold mountains | are mountains created where two or more tectonic plates are pushed together, compressing the rocks and folding them upwards |
| conservative plate boundaries | occur when two plates slide past each other. They move at different speeds. The plates get locked together and pressure builds up until it is released as an earthquake. |
| magnitude | measures the strength of an earthquake. It is measured on the Richter scale |
| Richter scale | Richter scale |
| tropical cyclones requirements | ocean surface temperatures of at least 27oC, ocean depth of at least 60 meters, very little shear wind and these conditions must occur between 5o and 20o north or south of the equator to form |
| why tropical cyclones need those conditions | provides the energy to evaporate more water that rises, and condenses, releasing huge amounts of energy, the 5o and 20o north or south of the equator mean that there is an optimal amount of Coriolis force (rotation of the earth) to make the air spin fast enough, change in wind speed or direction prevents the stoppage of the vertical development. |
| how tropical cyclones start | Clusters of thunderstorms grow and spin as warm air rises, cools, and condenses, releasing heat. This intensifies the low-pressure area, drawing more air toward the storm's centre. Cumulonimbus clouds form, and cooler air sinks, creating the eye. Tropical cyclones gain energy from warm ocean moisture. Tropical cyclones form May-November in the Northern Hemisphere (spin clockwise) and November-May in the Southern Hemisphere (spin counterclockwise). |
| causes of flooding | weather, previous weather, soil and rock type, relief, earthquakes, volcanoes and tropical cyclones, deforestation, urbanisation, agriculture, climate change |
| weather - causes of flooding | heavy, intense rainfall can exceed the infiltration capacity of the soil and lead to an increase in overland flow. Steady prolonged rainfall can saturate the soil and caused the water table to rise, reducing infiltration capacity. Overland flow will occur if snow melt is rapid and the ground beneath frozen |
| previous weather - causes of flooding | antecedent soil moisture refers to the amount of water in the soil before a rainfall event. The more saturated the soil, the less infiltration and the more overland flow |
| soil and rock type - causes of flooding | Impermeable soils and rocks, such as clay or granite, have a low infiltration capacity and percolation rate, which leads to greater overland flow |
| relief - causes of flooding | Steeper gradients can lead to faster overland flow and water has little time to infiltrate |
| earthquakes volcanoes and tropical cyclones - causes of flooding | These natural hazards can produce tsunamis and storm surges that flood low-lying coastal areas |
| deforestation - causes of flooding | Cutting down trees reduces interception and infiltration |
| urbanisation - causes of flooding | Concrete and tarmac are impermeable surfaces that lead to more overland flow. Storm drains speed up the movement of water to the nearest river |
| agriculture - causes of flooding | overgrazing and leaving soil expose reduces interception. Ploughing down rather than across lopes quickly channels the water downwards. Heavy farm machinery compacts the soil, making it impermeable |
| climate change - causes of flooding | enhanced global warming may lead to a rise in sea levels, as well as more rainfall and storms in certain parts of the world |
| causes of drought | changes in atmospheric circulation patterns, air in high-pressure systems, El Niño, La Niña, warmer temp, agricultural practices, deforestation, building a dam |
| changes in atmospheric circulation - causes of drought | altering storm tracks and wind patterns. An example of this is patterns that prevent the northwards movement of the intertropical convergence zone into the Sahel region of Africa, which means that the moist rising air at the intertropical convergence zone does not move north to reach Sahel |
| air in high pressure systems - causes of flooding | sinks and rain clouds generally do not form. If the sinking air covers a large area than normal or becomes prolonged, droughts can occur |
| El Niño - causes of drought | weather event where the surface water in the Pacific Ocean along South America rises in temperature. These warmer waters change circulation patters and alter storm patters and can cause droughts in Australia |
| La Niña - causes of drought | is the counterpart to El Niño and is when the surface water in the Pacific Ocean along South America decreases in temperature. The cooler waters contribute to drier conditions in parts of north and South America |
| warmer temps - causes of drought | warmer temperatures worldwide from climate change leads to decreased rainfall and therefore leading to more drought events |
| agricultural practices - causes of drought | can make land more vulnerable to drought. Irrigation techniques have increased farmer's dependence on water. Overcultivation and overgrazing can lead to soil compaction, and the soil is less able to hold water. As the soil becomes drier, it is vulnerable to erosion and eventually desertification |
| deforestation - causes of drought | decreases soil infiltration and increases soil erosion |
| building a dam - causes of drought | building a dam on a large river can cause drought downstream of the dam by reducing the flow of water |
| impacts of natural hazards | tectonic events, tropical cyclones, flooding, drought |
| tectonic events - impacts of natural hazards | earthquake-resistant structures, fire prevention measures like smart meters reduce risks, while understanding volcanic patterns aids tsunami predictions for timely evacuations |
| tropical cyclones - impacts of natural hazards | Predicting and preparing for tropical cyclones by tracking them with satellites and implementing protective measures like cyclone shelters, elevated buildings, and coastal embankments directly mitigate impacts such as flooding, loss of life, financial losses, and damage to infrastructure. These strategies also help preserve crops and habitats by protecting agricultural areas and maintaining clean water supplies, thereby reducing the risk of water-related diseases |
| flooding - impacts of natural hazards | involves monitoring rainfall, use of flood barriers like dams, land-use planning prioritizes higher ground for settlements and uses sandbags |
| drought - impacts of natural hazards | include desalination, drought-tolerant crops, agricultural improvements such as bunds help mitigate impacts |
| strategies for managing natural hazards | tectonic, tropical cyclones, flooding, drought |
| tectonic - managing natural hazards | Prediction and preparation for tectonic events are vital for disaster management. Monitoring and warning systems provide early alerts, and land use zoning places essential services in low-risk areas. Constructing earthquake-resistant structures enhances resilience, while disaster preparation involves plans, drills, and emergency supplies. Clear evacuation plans enable swift relocations, and international aid supports recovery in affected regions. |
| tropical cyclones - managing natural hazards | Tropical cyclones are predicted through satellite tracking for monitoring and warning. Preparation includes cyclone shelters, stilted buildings, disaster plans, drills, and emergency supplies. Evacuation and rebuilding efforts, along with international aid, are vital after a cyclone, while coastal embankments and mangrove swamps help reduce storm surge impacts |
| flooding - managing natural hazards | Flood prediction relies on monitoring rainfall and river discharge with storm hydrographs for warnings. Preparation includes flood barriers and afforestation, while land use planning prioritizes higher ground. During floods, shelters and rescue operations are vital, with recovery focused on rebuilding and using sandbags and pumps |
| drought - managing natural hazards | Drought prediction relies on monitoring precipitation and temperature. Preparation includes ensuring emergency water supplies and increasing water supply through dams, reservoirs, wells, and aquifers. Conservation strategies involve using drought-tolerant crops and improving agricultural practices. Governments also stockpile water, food, and medicine, with international aid supporting affected regions. |
| advantages of natural hazards | Volcanoes produce fertile soils for high crop yields and offer opportunities for extraction of minerals like sulphur and gold, as well as geothermal energy resources. Flooding contributes to the deposition of silt on farmland, providing vital food and water sources and enabling building on adjacent flat land. |
| why we need to recycle rocks and minerals - sustainable use of rocks and minerals | recycling uses less energy than processing the ores and recycling also produces less waste and therefore reduces the risk of pollution |
| legislation - sustainable use of rocks and minerals | can be achieved by the government passing laws that require manufactures to become responsible for recycling and reusing |
| water rich countries | have plentiful fresh water supply |
| water poor countries | have scare fresh water supplies |
| water conflict | is conflict between countries, states, or groups over access to water resources |
| physical water scarcity | is a situation in which there is simply not enough water for human needs |
| economic water scarcity | is a situation in which there is enough water available, but the money does not exist to extract it and/or treat it for human needs |
| sanitation systems | which ensure that dirty water does not mix with water intended for human use and water treatment processes which ensure that the water supplied to people is safe to drink |
| urban areas access to drinking waters | have higher access to safe drinking water because there is more wealth/more wealthy people in cities, large numbers of people can work together to pressurise authorities to provide safe water, and it is cheaper to install piped water when people live closer together |
| why dams are sustainable | alternative for burning fossil fuels as no greenhouse gases are produced |
| why dams are unsustainable | reservoir can become silted due to material carried into it by rivers, dam structure under a lot of pressure can deteriorate and eventually fall, have negative effects on the environment and aquatic organisms |
| global inequalities in sewage and water treatment | means that undeveloped countries (LEDC’s) have difficulty treating water and sewage compared to developed countries (MEDC’s) as people aren’t as educated and can’t put pressure on the government |
| effect of acid rain on organisms in rivers and lakes | a lower pH makes the environment intolerable for aquatic life, fish egg laying is reduced, and young fish are malformed, leaching of heavy metals such as aluminium, lead and mercury from the soil into the water, aluminium clogs fish gills and causes suffocation, minerals essential for life are washed out of the lake or river therefore reducing algae growth and leaving less food for aquatic animals. |
