8.2 - How We Use Natural Resources
Mechanised farming and its environmental consequences
Mechanised farming has transformed food production since the 1960s, relying on machinery to boost efficiency. While this has increased food output, it has also introduced several environmental challenges.
Key features of mechanised farming
- Industrial scale operations - Large-scale farming has expanded, using machines like tractors and combine harvesters instead of manual labour.
- Increased field sizes - Larger fields have been created to make production more cost-effective, often by removing natural barriers.
- Speed of processes - Tasks such as ploughing, milking, and harvesting are completed much faster with machinery, raising overall food volume.
Environmental impacts of mechanised farming
- Biodiversity loss - The removal of hedgerows to enlarge fields reduces habitats for wildlife, leading to a decline in species diversity.
- Chemical pollution - Greater use of artificial fertilisers and pesticides contaminates water systems like streams, harming aquatic organisms.
- Specialised animal feed - Livestock are often fed growth-promoting substances.
- Soil erosion - Heavy machinery contributes to soil erosion, degrading land quality.
Commercial fishing and its effects on marine ecosystems
The rising global demand for fish has led to intensified commercial fishing practices, often mechanised for larger catches. While this meets food needs, it poses serious threats to marine environments.
Methods of commercial fishing
- Trawling - Involves dragging massive nets through the water to catch fish, capturing large quantities at once.
- Dredging - Uses metal frames dragged along the seabed to collect shellfish, disrupting underwater environments.
- Aquaculture - Fish farms breed fish and shellfish in controlled enclosures, aiming to supplement wild catches.
- Mechanisation - Since the 1950s, fishing has relied on bigger nets and advanced technology for increased efficiency.
Environmental impacts of commercial fishing
- Over-fishing - Excessive harvesting of species like haddock has endangered populations, disrupting food chains as other species are affected.
- Seafloor damage - Dredging destroys marine habitats on the ocean floor, disturbing organisms and altering ecosystems.
- Fish farm waste - Overcrowding in aquaculture leads to significant waste, which, when released, causes algae blooms that deplete oxygen in water.
- Oxygen depletion - Algae growth from farm waste reduces oxygen levels, leading to the death of other aquatic plants and animals.
Energy demands leading to deforestation and related impacts
Growing energy needs have driven deforestation, the large-scale removal of trees, to provide fuel and space for energy infrastructure. This practice significantly alters landscapes and contributes to broader environmental issues.
Causes of deforestation for energy
- Fuel source - Trees are cut and burnt as a direct source of energy in many regions.
- Power station construction - Forests are cleared to build facilities, including those for hydroelectric power (HEP).
- Hydroelectric projects - Large areas along rivers are deforested to make way for dams, supporting renewable energy generation.
Environmental impacts of deforestation
- Carbon emissions - Trees absorb carbon dioxide (CO2); their removal or burning releases CO2 into the atmosphere, contributing to global warming.
- Habitat loss - Forests host around 70% of terrestrial species; clearing them eliminates habitats, risking extinction for many plants and animals.
- Soil erosion - Without tree roots to anchor soil, exposed land erodes more easily, with sediment entering waterways and damaging aquatic habitats.
- Flooding risk - Trees intercept rainfall; their absence increases surface runoff, heightening the likelihood of floods in surrounding areas.
Mining activities and their environmental challenges
Mining extracts valuable resources like fossil fuels (coal, oil, and gas) to meet energy demands, but it disrupts ecosystems through various extraction methods.
Types of mining practices
- Surface mining - Removes vegetation, soil, and rock layers to access resources near the surface.
- Sub-surface mining - Involves creating deep shafts to reach underground deposits.
- Fracking - Extracts shale gas by injecting high-pressure liquid into rock to fracture it, releasing trapped gas.
Environmental impacts of mining
- Habitat destruction - Mining operations clear land, reducing biodiversity.
- Pollution - Waste from mining, including toxic substances like mercury and lead, contaminates soil, groundwater, drinking water, and air.
- Water consumption - Large volumes of water are used in mining processes, straining local supplies.
- Climate change contribution - Burning extracted fossil fuels releases CO2, exacerbating global warming, while the resources themselves are non-renewable and unsustainable.
Water management practices and their ecological effects
Managing water resources to address shortages or seasonal variability often involves large-scale engineering solutions. While these ensure a steady water supply, they can disrupt natural systems and affect biodiversity.
Strategies for water management
- Dams and reservoirs - Dams trap river water to form reservoirs, providing a consistent supply throughout the year.
- Water transfer systems - Canals and pipes move water from areas of surplus to regions facing shortages.
- Controlled river flow - Water is released from dams at regular intervals, creating a more uniform flow than natural river patterns.
Environmental impacts of water management
- Habitat flooding - Reservoirs submerge large areas of land, destroying terrestrial habitats and agricultural zones.
- Species migration barriers - Dams prevent species like trout from migrating upstream to spawn, disrupting life cycles.
- Reduced biodiversity - Uniform river flows from controlled releases alter ecosystems, often lowering species diversity.
- Sediment disruption - Reservoirs trap sediment, reducing downstream soil fertility.
- Non-native species - New aquatic environments in reservoirs can support invasive species, altering local ecosystems.
- Energy and emissions - Pumping water over long distances in transfer systems consumes significant energy, releasing greenhouse gases that contribute to climate change.
- Source area shortages - Transferring water can deplete supplies in donor regions, particularly during drier periods.
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