It’s not possible to use natural resources for food, water and energy on such a large scale without there being an impact on the the environment and ecosystems. Landscapes have been altered dramatically but with improving technology this impact can be managed and minimised to some extent.
Mechanisation of agriculture
- Since the 1960s there has been an increase in large-scale, industrial farming where work is increasingly done by machinery (e.g. tractors, combine harvesters) instead of people.
- Industrial farming can increase food production because processes such as milking become quicker and more efficient.
But, this has had an effect on environments and ecosystems. Field sizes have increased to accommodate machinery and allow more food to be produced. This has involved the removal of hedgerows which has led to a decrease in biodiversity. The increased use of heavy machinery causes soil erosion as well. Also, the amount of chemicals used has increased through the use of chemical fertilisers and pesticides. Animals are sometimes given special food to promote growth. If these chemicals are leached (washed) into water supplies then they can harm or kill organisms.
Commercial fishing to provide food
- Global demand for fish is increasing and to meet this demand most fish and seafood is caught by commercial fishing methods. These include trawling (towing huge nets behind boats) and dredging (draging a metal frame along the seabed to catch shellfish).
- In a similar way to farming, fishing has become increasing mechanised over the past 60 years. Boats can now carry bigger nets and bring home bigger catches to meet the increasing demand for fish.
- Fish farms are also used to breed fish and shellfish in contained spaces.
But, this has had an effect on environments and ecosystems. Overfishing of some species (e.g. cod) means that some species are now endangered. Lower numbers of one species can then affect the rest of the food chain and ecosystem. Dredging damages seafloor habitats and disturbs other organisms such as starfish. Fish farms can often be overcrowded and large numbers of fish produce large amounts of waste. If this is released into the environment it can cause large amounts of algae to build up. The algae absorbs lots of oxygen from the water causing other plants and animals to die from lack of oxygen.
Demand for energy is increasing deforestation
- Deforestation for fuel, construction materials or to use the land for farming has been carried out for thousands of years. However, the rate of deforestation has significantly increased. Temperate forests in the northern hemisphere have been reduced to a bare minimum and there is only 2% of tropical rainforest left worldwide.
- In some countries, where a large river runs through forest (e.g. the Amazon in Brazil), forest is being cut down to create space for hydroelectric power (HEP) stations. This provides renewable energy to meets our energy demands but the intial construction involves building a dam which means flooding large areas of forest.
Deforestation has many impacts on the environment and ecosystems. Trees remove carbon dioxide from the atmosphere so by reducing the amount less carbon dioxide is removed. Also burning trees to clear forest releases carbon dioxide further increasing the amount in the atmosphere. This contributes to global warming. Deforestation also destroys habitats; around 70% of all land-based plants and animals live in forests, if their habitats are destroyed they are at risk of extinction. Removing trees also exposes the soil to erosion; eroded soil can enter rivers damaging the habitats of fish and other freshwater organisms. Deforestation reduces interception making flooding more likely which can also damage habitats.
- Fossil fuels are a major source of energy, these are removed from the ground by mining. Surface mining is where a large amount of vegetation, rock and soil are stripped away so miners can reach the material they want. Sub-surface mining involves digging deep shafts below the ground’s surface.
- Fracking has been developed recently to extract shale gas (natural gas which is trapped in shale rock underground). Liquid is pumped into rock at high pressure causing the rock to fracture releasing the gas.
Mining has significant impacts on environments and ecosystems. Waste from mines pollutes soil, groundwater, drinking water and air. Pollutants include mercury and lead which are very toxic to plants, animals and humans. Habitats are destroyed to make way for the mines, reducing biodiversity. Coal, oil and gas are non-renewable sources and are therefore not sustainable. They release carbon dioxide when burned, contribuing to global warming.
Water transfer schemes to provide water.
- Water is often not where it is most needed (e.g. southeast UK has high population but low rainfall). To solve this issue canals and pipes are used to transfer water from areas of surplus to areas of deficit.
Water transfer causes problems for environments and ecosystems. Large-scale engineering is required to put these transfer schemes into place which can damage ecosystems. Water transfer can create water shortages in the areas where the water is coming from, particularly in drier years, increasing pressure on the ecosystem. Lots of energy is required to pump water over long distances if the route doesn’t naturally flow downhill. This can release greenhouse gases such as carbon dioxide, contributing to global warming. Water transfer schemes also often involve the construction of dams and reservoirs which have significant impacts on the environment and local ecosystem.