Resource Supply and Demand
- Resources, such as food, energy and water, are needed for basic human development
- Without enough nutritious food, people can become malnourished, making them more likely to get ill, stopping them from working and doing well at school
- A good supply of energy is needed for a basic standard of living; to provide lighting, heat for cooking and for industry and transport
- People need a constant supply of good, safe water for drinking, cooking and washing at home and to produce food, clothes and other products
- Consumption of food, energy and water around the world is increasing because of the rising population and economic development
- The global population is increasing; in 2011 it was just over 7 billion and is expected to reach 9 billion by 2040, meaning more people require more resources
- Death rates have fallen because of advances in medical knowledge and improved living conditions
- Birth rates in some countries remains high
- Increased demand for one resource can increase demands for another; more people means that more food needs to be grown, which increases demand for water
- Economic development means that people are getting wealthier, especially in EDCs and wealthier people have more disposable income
- They have more money to spend on food, often buying more than necessary and buying more luxurious foods
- They can afford cars, fridges, televisions etc., all of which use energy and require water and energy during manufacturing
- More people can afford flushing toilets, showers, dishwashers etc., increasing water usage
- The global population is increasing; in 2011 it was just over 7 billion and is expected to reach 9 billion by 2040, meaning more people require more resources
- Many countries are trying to increase supplies of food, water and energy however, climate, geology, conflict, poverty and natural hazards are some factors that limit supplies, meaning that supply can’t meet demand
- Some countries have very low rainfall, and others are impacted by climate change, so water supplies are limited; this also effects how much food they can grow
- In February 2007, 70,000 people in Mexico City protested the price of tortillas
- The price increased because Mexico had a poor corn harvest so there was less supply to make tortillas
- At the same time, demand for corn increased because it can also be used to make biofuels for cars
- In February 2007, 70,000 people in Mexico City protested the price of tortillas
- Some countries don’t have reserves of fossil fuels and may not have a suitable landscape for generating renewable energy; geology can also limit water supply as when rain falls on permeable rock, it flows into the rock and form underground water stores that are difficult to access
- War can disrupt transport of resources
- Some countries can’t afford the technology to exploit available natural resources
- Events such as tropical storms, earthquakes and volcanic eruptions can damage agricultural land and destroy infrastructure
- Some countries have very low rainfall, and others are impacted by climate change, so water supplies are limited; this also effects how much food they can grow
Human Use of the Environment
- Farming is becoming more mechanised
- Since the 1960s, there has been a growth in large-scale, industrial farming where processes are increasingly done by machines like tractors and combine harvesters than people
- Industrial farming can increase the amount of food that can be produced because processes such as milking, ploughing and harvesting can be done more quickly
- However, changes to farms have had impacts on ecosystems and the environment
- Fertilisers, herbicides and pesticides pollute the soil and leach into water sources causing eutrophication, and bioaccumulation
- Soil erosion increases due to heavy machinery and exposure to wind and rain
- Biodiversity is reduced by growing a single crop because the prior habitat is often destroyed, creating monoculture
- Soil nutrients are lost through over-farming and are drained away by water in a process called leaching
- Commercial fishing methods increase fish catches
- Global demand for fish is increasing; it was 9.9kg per person a year in the 1960s and was 19.2kg in 2012
- Most fish and seafood are provided by commercial fishing methods which include trawling and dredging the seabed to harvest shellfish
- Since the 1950s, fishing has become increasingly mechanised, meaning that boats can now carry bigger nets and haul in bigger catches than used to be possible, helping to meet demand for fish
- Aquaculture (fish farms) are also being used to breed fish and shellfish in contained spaces
- Commercial fishing is having a number of impacts on ecosystems and the environment
- Over-fishing of some fish means that some species are now endangered because they are taken faster than populations can recover
- Decreasing the number of one species in an ecosystem can have knock-on impacts on other species
- Species migrate further out meaning more fuel needs to be used to get to them, increasing fossil fuel consumption and water pollution
- By-catch can be 90% of a total catch and might include centuries-old pieces of coral, fish too small to eat, and large sea mammals
- Some throw back by-catch to meet quota
- Trawling and dredging can damage seafloor habitats and disturb organisms such as sea urchins and starfish
- Fish farms are overcrowded and often breed disease and lots of waste is produced which is flushed into the ocean
- Cyanide is sometimes used to make the fish easier to catch, however it kills whole ecosystems; for one fish caught, a square metre of coral reef is destroyed with this method
- Over-fishing of some fish means that some species are now endangered because they are taken faster than populations can recover
- Demand for energy is increasing deforestation
- Increasing energy demand increases deforestation as the trees are burnt as fuel or cleared to make way for power stations or to grow biofuels in
- In some countries where a large river runs through an area of forest, forest is being destroyed to make way for hydroelectric power stations which provide renewable energy to help meet the demands
- However, HEP stations involve building a dam, which floods large areas of forest
- Deforestation has many environmental impacts
- Trees remove CO2 from the atmosphere, and burning vegetation to clear forest releases CO2; this contributes to global warming
- Forests provide an important habitat; around 70% of all land-based plant and animal species live in forests, so if these habitats are lost species could become extinct
- Removing trees exposes the soil and makes it easier to erode; eroded soil can enter rivers and streams, damaging the habitats of fish and other freshwater organisms
- Trees intercept rainfall, so removing them makes flooding more likely, this can damage habitats
- Tree roots store water and nutrients and bind soils together; the loss of trees leads to leaching of soils, increased surface run-off and soil erosion, all of which reduce agricultural productivity
- Mining to provide energy has environmental impacts
- Fossil fuels are major sources of energy that are removed from the ground by mining
- Surface mining is where large areas of vegetation, soil and rock are stripped away so that miner can reach the surface they want
- Sub-surface mining involves digging deep shafts below ground surface
- Recently, a technique called fracking had been developed to extract shale gas (natural gas that is trapped inside shale rock); liquid is pumped into the rock at high pressure, causing the rock to fracture, releasing the gas which is then collected as it comes out of the production well
- Fossil fuels are major sources of energy that are removed from the ground by mining
- Mining has lots of impacts on the environment and ecosystems
- Waste from mines can pollute soil, rivers, oceans, groundwater and air; pollutants include mercury, sulphur, arsenic and lead, which are very toxic to plants, animals and people
- In the USA people living near fracking sites can set fire to their tap water because it contains large amounts of methane
- When the Deep Water Horizon oil well exploded in the Atlantic Ocean near Florida in 2010, about 4.9 million barrels worth of oil leaked into the ocean, affecting the ocean ecosystem severely
- Habitats are destroyed to make way for mines, leading to loss of biodiversity
- Mining uses a huge amount of water which is a limited resource creating drought
- Coal, oil and gas are unsustainable and non-renewable energy sources which release CO2 when burnt, contributing to global warming
- Sulphur dioxide and nitrogen oxides can cause acid rain
- Waste from mines can pollute soil, rivers, oceans, groundwater and air; pollutants include mercury, sulphur, arsenic and lead, which are very toxic to plants, animals and people
- Reservoirs can provide a reliable water supply
- Seasonal variations in rainfall or unpredictable rainfall can cause a water shortage at certain times of year, so water storage needs to be increased
- Building a dam across a river traps a large amount of water behind the dam, creating a reservoir which provides a reliable source of water all year
- However, dams and reservoirs have environmental impacts
- Reservoirs flood large amounts of land, destroying habitats and agricultural land
- The Three Gorges Dam in China has a reservoir nearly 650km long and when thousands of towns and villages were submerged, 1.3 million people were displaced for it
- Reservoirs impact local ecosystems; water is often released through the dam at regular intervals making the river flow much more uniform, this often reduces species biodiversity
- Dams act as a barrier to species’ movements, such as salmon which migrate upstream to lay eggs
- Reservoirs create new aquatic environments, which can become home to non-native species
- The natural flow of sediment downstream is disrupted, reducing the fertility of areas downstream
- Water temperatures could become warmer on the surface and colder deep down upstream whilst becoming warmer downstream, threatening extinction
- Extremely deep water could become a dead zone with too little oxygen to survive
- Reservoirs flood large amounts of land, destroying habitats and agricultural land
- Water transfer schemes move water to places where it’s needed
- Water is often not where it is most needed so water transfers use canals and pipes to move water from a river that has surplus water to a river that has a water shortage
- This can cause problems for ecosystems and the environment
- Large-scale engineering works are needed to create new channels; these can damage ecosystems
- There may be water shortages in areas where the water is coming from, particularly in dry years; this puts pressure on local ecosystems
- Lots of energy is needed to pump the water over long distances if there isn’t a natural downhill route; this can release greenhouse gases, adding to climate change
- Nutrient imbalances from the change of water could kill species
- The introduction of water to a new area can also spread non-native invasive species which can threaten the ecosystem
- Water transfer schemes often involve building dams and reservoirs