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2024 Cambridge IGCSE Environmental Management (0680) Practice Paper with Answers

Thinka Jun 2024 (V3) Cambridge IGCSE-Style Mock — Environmental Management (0680)

160 marks210 mins2024

An original Thinka practice paper modelled on the structure and difficulty of the Jun 2024 (V3) Cambridge IGCSE Environmental Management (0680) paper. Not affiliated with or reproduced from Cambridge.

Paper 1 Theory (0680/13)

Answer all questions. Show your working where required. Calculators are allowed.

8 Question · 80 marks

Question 1 · short_answer

10 marks

The table below shows information about global earthquakes recorded over a one-year period. Richter Magnitude: Minor (3.0 - 3.9), Average global frequency per year: 49000, Average damage: Rarely felt but recorded. Richter Magnitude: Moderate (5.0 - 5.9), Average global frequency per year: 800, Average damage: Significant damage to poorly built structures. Richter Magnitude: Major (7.0 - 7.9), Average global frequency per year: 18, Average damage: Serious damage over large areas. Richter Magnitude: Great (8.0 or higher), Average global frequency per year: 1, Average damage: Severe destruction across several hundred kilometres. (a) Describe the relationship shown in the table between Richter magnitude and the average global frequency per year. [2] (b) State two ways scientists can monitor a volcano to predict an eruption. [2] (c) Explain why the destructive effects of an earthquake of magnitude 6.5 might be much greater in a developing country (LEDC) than in a developed country (MEDC). [4] (d) Suggest why some people continue to live near active volcanoes. [2]

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Worked solution

(a) As the Richter magnitude increases, the average global frequency per year decreases. For example, Minor earthquakes (3.0-3.9) occur 49,000 times a year while Great earthquakes (8.0+) occur only once a year. (b) Monitoring seismic activity (using seismometers to detect mini-shocks) and measuring gas emissions (using spectrometers to detect changes in sulfur dioxide). (c) LEDCs often have poorer building infrastructure which collapses more easily. They may lack emergency services, early warning systems, and resources for quick rescue operations. High population densities in urban slums also increase casualties. (d) Volcanic soils are highly fertile and excellent for agriculture, geothermal energy can be harnessed, and tourism provides jobs.

Marking scheme

(a) [2 marks] 1 mark for stating that frequency decreases as magnitude increases. 1 mark for using comparative data from the table to support the statement. (b) [2 marks] 1 mark for each valid volcano monitoring method (e.g., gas analysis, seismology, ground deformation/tiltmeters, satellite thermal imaging). Max 2 marks. (c) [4 marks] Award up to 4 marks for explaining: low-quality building construction/lack of earthquake-proof designs [1], lack of emergency preparedness/rescue equipment [1], higher population density in vulnerable areas [1], limited medical facilities and financial resources for recovery [1]. (d) [2 marks] Award 1 mark for each valid reason (e.g., fertile volcanic ash for farming, geothermal energy, tourism industry, poverty/inability to move, mineral mining). Max 2.

Question 2 · short_answer

10 marks

(a) Define the term 'epicentre' of an earthquake. [1] (b) Explain how tectonic plate movement at a conservative plate boundary causes earthquakes but does not form volcanoes. [3] (c) Describe three ways in which tsunami waves, triggered by underwater earthquakes, cause widespread coastal damage. [3] (d) State three emergency plans a local government should implement immediately after an earthquake occurs. [3]

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Worked solution

(a) The point on the Earth's surface directly above the focus where the earthquake originates. (b) At conservative boundaries, plates slide past each other. Friction causes them to stick, building up stress. When the pressure is suddenly released, energy waves travel through the crust as an earthquake. No volcanoes form because plates are not subducted or pulled apart, so no magma is created or allowed to rise to the surface. (c) Flooding of coastal lands destroys crops, powerful water energy collapses buildings/bridges, and the returning wave drags debris and sewage into the sea, polluting coastal waters. (d) Set up temporary emergency shelters, coordinate search-and-rescue teams to locate survivors, and distribute clean drinking water and medical aid.

Marking scheme

(a) [1 mark] Correct definition stating the point on the surface directly above the focus/origin. (b) [3 marks] 1 mark for sliding plates building friction/stress. 1 mark for sudden release of energy causing the earthquake. 1 mark for explaining that there is no subduction or rifting, hence no magma generation for volcanoes. (c) [3 marks] 1 mark for each valid impact (e.g., drowning/loss of life, structural damage to roads/bridges, salinisation of agricultural soil, water-borne disease outbreaks from contamination). Max 3. (d) [3 marks] 1 mark for each valid emergency action (e.g., deploying rescue teams, establishing shelters, providing clean water/food, turning off gas/electricity mains to prevent fires, setting up field hospitals). Max 3.

Question 3 · short_answer

10 marks

In a marine management zone, the annual catch of Atlantic Cod was recorded over a ten-year period. Year 1: 800 thousand tonnes. Year 5: 450 thousand tonnes. Year 10: 200 thousand tonnes. (a) Calculate the percentage decrease in cod catch between Year 1 and Year 10. Show your working. [2] (b) Explain the term 'overfishing' in the context of sustainable yields. [2] (c) Describe how the implementation of 'minimum mesh sizes' for fishing nets helps to conserve fish stocks. [3] (d) Explain how 'closed seasons' can protect marine species during vulnerable stages of their life cycle. [3]

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Worked solution

(a) Decrease = 800 - 200 = 600 thousand tonnes. Percentage decrease = (600 / 800) * 100 = 75%. (b) Overfishing occurs when fish are caught at a faster rate than they can reproduce and replenish their population, reducing the fish stock below its sustainable level. (c) Minimum mesh sizes ensure that the holes in fishing nets are large enough for young, juvenile fish to escape. This allows them to reach breeding age and reproduce before being caught, sustaining the population. (d) Closed seasons ban fishing during specific months. This protects fish during their spawning season, ensuring they can lay eggs without disturbance, and protects young fry while they are growing.

Marking scheme

(a) [2 marks] 1 mark for correct working shown (e.g., 600 / 800 * 100). 1 mark for the correct answer of 75%. (b) [2 marks] 1 mark for identifying that catching exceeds reproduction rate. 1 mark for mentioning the long-term decline in fish stocks/threat to sustainability. (c) [3 marks] 1 mark for noting that small/young/juvenile fish escape. 1 mark for stating that these fish survive to reach sexual maturity/breeding age. 1 mark for explaining that this sustains or increases future fish populations. (d) [3 marks] 1 mark for identifying spawning/breeding times as the closed period. 1 mark for explaining that adult fish can reproduce undisturbed. 1 mark for noting that juvenile fish are protected from early capture, boosting recruitment rates.

Question 4 · short_answer

10 marks

(a) State two difficulties in enforcing international fishing quotas in the open ocean. [2] (b) Explain how marine reserves (no-take zones) can lead to a 'spillover effect' that benefits nearby commercial fishing areas. [3] (c) Describe three ecological impacts of using heavy bottom-trawling gear on seafloor ecosystems. [3] (d) State two methods, other than quotas or mesh sizes, used to reduce the amount of bycatch in commercial fishing. [2]

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Worked solution

(a) The vast size of the oceans makes physical patrolling difficult and expensive, and ships can easily operate under different flags to bypass laws. (b) Inside a marine reserve, fish populations grow and breed without human interference. As the reserve becomes crowded, adult fish and larvae migrate out of the protected boundaries into adjacent waters, where they can be sustainably caught by commercial fishers. (c) Bottom trawling scrapes and destroys coral reefs/seafloor habitats, stirs up sediment which blocks light for photosynthesis, and indiscriminately catches non-target benthic organisms. (d) Using pole-and-line fishing instead of nets, and installing turtle excluder devices (TEDs) on trawl nets.

Marking scheme

(a) [2 marks] 1 mark for each valid difficulty (e.g., high cost of patrol vessels, vast areas of open ocean, lack of jurisdiction in international waters, flag-of-convenience registration). Max 2. (b) [3 marks] 1 mark for explaining that fish populations breed and multiply rapidly inside the safe zone. 1 mark for noting the resulting high density of fish. 1 mark for explaining the migration/spillover of excess fish into harvestable areas. (c) [3 marks] 1 mark for each valid impact (e.g., physical destruction of coral/sponge habitats, turbidity/siltation blocking sunlight, non-selective bycatch of bottom-dwelling species, disruption of benthic food webs). Max 3. (d) [2 marks] 1 mark for each valid method (e.g., bird-scaring lines on longlines, turtle excluder devices (TEDs), acoustic deterrents/pingers, circle hooks, line fishing instead of netting). Max 2.

Question 5 · short_answer

10 marks

(a) Describe how electricity is generated in a geothermal power station. [3] (b) State two environmental advantages of using geothermal energy compared to burning fossil fuels. [2] (c) Suggest two reasons why geothermal energy cannot be used as a major energy source in all countries. [2] (d) Explain why geothermal energy is classified as a renewable energy resource. [3]

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Worked solution

(a) Cold water is pumped underground into hot volcanic rocks where it is heated and turns into steam. This high-pressure steam rises to the surface, turning a turbine, which powers a generator to produce electricity. (b) It releases virtually no carbon dioxide, preventing global warming, and does not emit sulfur dioxide, which reduces acid rain. (c) Many countries are not located near tectonic plate boundaries where hot rocks are close to the surface, and deep drilling is extremely expensive. (d) It relies on the heat generated naturally by radioactive decay deep within the Earth's core. This heat source is virtually infinite and will not run out, and the water used can be re-injected and reheated continuously.

Marking scheme

(a) [3 marks] 1 mark for identifying steam produced by underground hot rocks. 1 mark for steam turning a turbine. 1 mark for the turbine driving a generator to produce electricity. (b) [2 marks] 1 mark for each valid advantage (e.g., no/minimal greenhouse gas emissions, no sulfur dioxide/acid rain, small land footprint compared to coal mines, constant/reliable output). Max 2. (c) [2 marks] 1 mark for geographical limitations (must be near tectonic boundaries/hotspots). 1 mark for high initial capital costs of deep exploration and drilling. (d) [3 marks] 1 mark for stating that the heat source is internal and continuous (radioactive decay in the Earth). 1 mark for noting it will not run out/is non-finite. 1 mark for explaining that water can be recycled/re-injected back into the system.

Question 6 · short_answer

10 marks

(a) State two air pollutants, other than carbon dioxide, released by burning coal in a power station. [2] (b) Explain the term 'enhanced greenhouse effect'. [3] (c) Suggest two advantages and one disadvantage of using solar panels to generate electricity for a remote village. [3] (d) State two ways energy efficiency can be improved in domestic homes to reduce the overall demand for electricity. [2]

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Worked solution

(a) Sulfur dioxide and nitrogen oxides. (b) The enhanced greenhouse effect is the warming of the Earth's atmosphere caused by human activities (such as burning fossil fuels) that release excess greenhouse gases. These gases trap more outgoing infrared radiation, preventing it from escaping into space, which raises global temperatures. (c) Advantages: It is a renewable source with zero emissions during operation, and it reduces the need for expensive grid infrastructure. Disadvantage: It is intermittent because it does not generate power at night or during heavy cloud cover. (d) Installing double-glazed windows to reduce heat loss and using energy-efficient LED light bulbs.

Marking scheme

(a) [2 marks] 1 mark for each correct pollutant (e.g., sulfur dioxide, nitrogen oxides, carbon monoxide, soot/particulates). Max 2. (b) [3 marks] 1 mark for identifying human activities releasing excess greenhouse gases (e.g., CO2, methane). 1 mark for explaining that these gases build up and trap more outgoing thermal/infrared radiation. 1 mark for linking this to an increase in global temperatures/climate change. (c) [3 marks] 1 mark for each of the two advantages (e.g., clean/no emissions, low running costs, ideal for off-grid areas). 1 mark for the disadvantage (e.g., weather-dependent, high initial cost, battery storage needed for night use). (d) [2 marks] 1 mark for each valid action (e.g., loft insulation, double glazing, LED lighting, energy-efficient appliances, smart thermostats). Max 2.

Question 7 · short_answer

10 marks

(a) State two differences between organic fertilizers (such as manure) and inorganic chemical fertilizers. [2] (b) Explain how the practice of 'intercropping' (growing two or more crops close together) promotes sustainable agriculture. [3] (c) Describe how trickle drip irrigation reduces the risk of soil salinisation in arid regions. [3] (d) State two reasons why crop rotation can reduce the need for synthetic chemical pesticides. [2]

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Worked solution

(a) Organic fertilizers are made from natural biological materials and improve soil structure, whereas inorganic fertilizers are synthetically manufactured chemicals that do not add organic matter to the soil. (b) Intercropping maximizes land use efficiency, reduces soil erosion because the ground has better plant cover, and increases biodiversity which naturally controls pests and diseases. (c) Trickle drip irrigation delivers water slowly and directly to the roots of the plants. This minimizes the amount of water lost to evaporation, preventing dissolved salts from being drawn up to the soil surface to form a salty crust. (d) It breaks the life cycles of pests that are specific to one crop type, and different crops attract different beneficial predatory insects that naturally control pests.

Marking scheme

(a) [2 marks] 1 mark for organic being natural/improving soil organic matter/humus. 1 mark for inorganic being chemical/synthetic/not improving soil structure. (b) [3 marks] 1 mark for continuous soil cover reducing wind/water erosion. 1 mark for complementary nutrient uptake (e.g., legumes fixing nitrogen). 1 mark for pest suppression due to mixed crop architecture. (c) [3 marks] 1 mark for direct delivery of water to roots with minimal runoff/waste. 1 mark for reducing water evaporation from the soil surface. 1 mark for explaining that preventing high evaporation stops capillary action from bringing salts to the surface. (d) [2 marks] 1 mark for interrupting the pest life cycle (pest host-plant is removed). 1 mark for improving soil health/plant vigour, making crops less susceptible to pest damage, or promoting natural predators. Max 2.

Question 8 · short_answer

10 marks

(a) Describe three environmental impacts of opencast (surface) mining before any restoration takes place. [3] (b) Explain how 'land reclamation' can be used to restore a former mine site to a safe and useful state. [3] (c) Suggest why treating mine waste heaps with alkaline materials can help prevent water pollution. [2] (d) State two benefits to local communities of converting a closed quarry into a recreational lake or nature reserve. [2]

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Worked solution

(a) It causes complete destruction of vegetation and habitats, leading to biodiversity loss; creates severe noise and dust pollution from blasting; and results in visual scarring of the landscape. (b) The deep pits are filled with waste rock and covered with stored topsoil. The land is then graded to prevent erosion and planted with native vegetation or crops to restore biological productivity. (c) Mine waste often contains sulfide minerals that react with rainwater to form highly acidic runoff (acid mine drainage). Adding alkaline materials neutralizes the acid, preventing toxic heavy metals from dissolving and washing into nearby streams. (d) It provides a recreational area for water sports or walking, and creates new jobs in local tourism and conservation.

Marking scheme

(a) [3 marks] 1 mark for each valid impact (e.g., habitat destruction, loss of biodiversity, dust/noise pollution, soil erosion, water contamination/acid mine drainage, visual pollution). Max 3. (b) [3 marks] 1 mark for mentioning backfilling/regrading the landscape. 1 mark for replacing saved topsoil. 1 mark for revegetating/planting trees or crops to stabilize the soil and restore ecosystems. (c) [2 marks] 1 mark for identifying that mine waste can produce acid runoff (acid mine drainage). 1 mark for explaining that alkaline materials neutralize this acid, preventing heavy metals from leaching into water supplies. (d) [2 marks] 1 mark for each valid community benefit (e.g., educational/recreational space, improved aesthetics/visual appeal, economic opportunities via eco-tourism, improved local biodiversity/nature access). Max 2.

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Paper 2 Management in Context (0680/23)

Answer all questions based on the provided environmental scenario (New Zealand). Standard plotting and mathematical calculations required.

3 Question · 78 marks

Question 1 · Theory

26 marks

The Hoki Fishery on the West Coast of the South Island, New Zealand

Hoki (Macruronus novaezelandiae) is one of New Zealand's most important commercial fish species. It is mainly harvested using mid-water and bottom trawling off the west coast of the South Island.

(a) (i) Explain why the marine ecosystem around the South Island of New Zealand has high biological productivity. [2]
(ii) State two advantages of using a quota system, such as the Total Allowable Commercial Catch (TACC), to manage the Hoki fishery. [2]

(b) A research vessel collected data on the average length of Hoki caught in a specific fishing zone over a six-year period:
- Year 1: 65 cm
- Year 2: 62 cm
- Year 3: 58 cm
- Year 4: 55 cm
- Year 5: 54 cm
- Year 6: 54 cm

(i) Describe how a researcher would plot a line graph of these data, including details on scale selection and axis labeling. [4]
(ii) Describe the overall trend shown by the data. [2]
(iii) Suggest two reasons for the trend observed in the Hoki average length over the six-year period. [2]

(c) Some fishing companies have suggested using larger mesh sizes in their trawl nets.
(i) Explain how using a larger mesh size helps to maintain sustainable fish stocks. [3]
(ii) State three other management strategies, besides quotas and mesh size, used to prevent overfishing. [3]

(d) A local marine reserve was established near the coast of the South Island to protect biodiversity.
(i) Describe how marine reserves can benefit surrounding, unprotected fishing areas. [2]
(ii) Suggest why some commercial fishers might initially object to the creation of a marine reserve. [2]

(e) Calculate the percentage decrease in the average length of Hoki from Year 1 to Year 6. Show your working. [4]

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Worked solution

(a) (i) High biological productivity is caused by upwelling of cold, nutrient-rich deep ocean water to the sunlit surface, stimulating the growth of phytoplankton which forms the base of the marine food web. (ii) It limits the total biomass of fish removed, preventing overfishing; it can be adjusted yearly based on scientific stock assessments. (b) (i) The x-axis should be labeled 'Year' (scale 1 to 6, 1 unit per block), and the y-axis 'Average length of Hoki / cm' (scale 50 to 70 with 2 cm intervals per block). Points should be plotted accurately and connected with straight lines. (ii) The average length of Hoki decreases rapidly from Year 1 (65 cm) to Year 4 (55 cm), then stabilizes at 54 cm by Year 5 and 6. (iii) Heavy fishing pressure targets larger adult fish, leaving smaller immature fish; selective pressure favors fish that mature at smaller sizes. (c) (i) Larger mesh sizes allow smaller, juvenile fish to escape the nets so they can survive, reach reproductive age, and contribute to replenishing the population. (ii) Closed seasons, closed areas (no-take zones), restriction on vessel numbers/licenses, and bans on destructive fishing gear. (d) (i) Spillover effect: adult fish migrate out of the reserve into fished zones, and larvae/eggs are dispersed by currents to restock adjacent areas. (ii) They lose access to traditional, potentially lucrative fishing grounds, which may increase travel times and fuel costs to fish elsewhere. (e) Decrease = 65 - 54 = 11 cm. Percentage decrease = (11 / 65) * 100 = 16.9%.

Marking scheme

(a) (i) Upwelling / nutrient-rich waters [1]; stimulates phytoplankton growth / photosynthesis [1].
(a) (ii) Any two from: prevents overexploitation; easily enforceable; dynamically adjusted based on scientific assessments; encourages economic efficiency [2].
(b) (i) Axes labeled correctly with units: x-axis: Year, y-axis: Average length / cm [1]; suitable linear scales covering at least 50% of the grid [1]; all points plotted accurately [1]; points connected with straight lines [1].
(b) (ii) Initial rapid decrease [1]; stabilizes/levels off from Year 4/5 onwards [1].
(b) (iii) Selective removal of large individuals/overfishing [1]; fish maturing at smaller sizes/fewer mature adults left [1].
(c) (i) Small/juvenile fish escape [1]; grow to adult size/reach reproductive age [1]; spawn/replenish the population [1].
(c) (ii) Any three from: closed seasons; marine protected areas/no-take zones; restrictions on engine size/vessel size; limit on fishing days/hours; restrictions on sonar/bycatch [3].
(d) (i) Spillover effect/migration of adults [1]; larval export/currents carrying eggs and larvae to fished areas [1].
(d) (ii) Reduced fishing grounds [1]; increased competition in remaining open zones/longer travel times [1].
(e) Correct change calculated: 11 cm [1]; formula: (11 / 65) * 100 [1]; correct calculation: 16.9% (accept 17%) [1]; correct unit: % [1].

Question 2 · Theory

26 marks

Sustainable Agriculture and Soil Management in the Canterbury Plains, New Zealand

The Canterbury Plains are famous for high-production agriculture, but intensive dairy farming has raised concerns about nitrate leaching into groundwater and local streams.

(a) (i) Explain how intensive dairy farming can lead to the eutrophication of local freshwater streams. [4]
(ii) State two symptoms of eutrophication in a freshwater lake. [2]

(b) An agricultural scientist conducted an experiment to investigate the effect of different riparian buffer strips (vegetated zones alongside streams) on the concentration of nitrates in runoff water. She set up three experimental plots on a hillside:
- Plot A: Bare soil (no buffer strip)
- Plot B: Grass buffer strip (5 meters wide)
- Plot C: Native shrub and tree buffer strip (5 meters wide)
Each plot received the same volume of artificial rainfall and fertiliser application.

The nitrate concentration in the runoff water entering the stream was measured:
- Plot A: 45 mg/L
- Plot B: 18 mg/L
- Plot C: 9 mg/L

(i) Identify the independent variable and the dependent variable in this investigation. [2]
(ii) State three factors that must be kept constant (controlled variables) to ensure a fair test. [3]
(iii) Suggest why the scientist repeated the measurements three times for each plot. [1]
(iv) Calculate the percentage reduction in nitrate concentration achieved by the native shrub and tree buffer strip (Plot C) compared to the bare soil (Plot A). Show your working. [3]

(c) (i) Describe how planting shelterbelts (windbreaks) reduces soil erosion in Canterbury. [3]
(ii) Explain how organic fertilisers, such as manure, improve soil structure compared to inorganic chemical fertilisers. [3]

(d) (i) Suggest why drip irrigation is a more sustainable method of watering crops than overhead spray irrigation. [3]
(ii) State two ways climate change may affect future water availability for agriculture in Canterbury. [2]

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Worked solution

(a) (i) Nitrogen from cow urine/manure and chemical fertilisers washes off the land during rain (surface run-off) or leaches through the soil into groundwater. This runoff enters streams, increasing nutrient levels, causing rapid growth of algae (algal bloom). The algae block sunlight, causing aquatic plants to die; decomposers (bacteria) feed on dead material, multiplying rapidly and consuming dissolved oxygen, leading to the suffocation of fish. (ii) Algal blooms and low dissolved oxygen levels (or death of fish). (b) (i) Independent: type of buffer strip. Dependent: nitrate concentration in runoff water. (ii) Volume of artificial rainfall, slope angle of the plots, quantity/type of fertiliser applied. (iii) To increase the reliability of the results and identify anomalies. (iv) Reduction = 45 - 9 = 36 mg/L. Percentage reduction = (36 / 45) * 100 = 80%. (c) (i) Tree roots bind the soil; the physical barrier of trees reduces wind speed at ground level, preventing loose topsoil from being blown away. (ii) Organic matter binds soil particles into aggregates, improves water retention, and provides humus which feeds soil organisms like earthworms. (d) (i) Drip irrigation applies water directly to the root zone, reducing evaporation losses, minimizing weed growth, and preventing waterlogging/salinization. (ii) Increased frequency of severe droughts, and reduced river flows due to declining snowpack/glaciers in the Southern Alps.

Marking scheme

(a) (i) Runoff/leaching of animal waste or chemical fertilisers [1]; nutrients stimulate rapid algal growth / algal blooms [1]; light is blocked causing sub-surface plants to die [1]; aerobic bacteria decompose dead plants and deplete dissolved oxygen [1].
(a) (ii) Any two from: algal blooms; green/turbid water; anaerobic conditions/foul smell; death of fish/biodiversity loss [2].
(b) (i) Independent variable: Type of buffer strip / vegetation type [1]; Dependent variable: Nitrate concentration in runoff water [1].
(b) (ii) Any three from: slope angle; soil type; volume of water applied; concentration/type of fertiliser applied; duration of rainfall [3].
(b) (iii) To increase reliability / minimize experimental error / find anomalies [1].
(b) (iv) Correct reduction: 36 mg/L [1]; calculation: (36 / 45) * 100 [1]; final answer: 80% [1].
(c) (i) Physical barrier reduces wind speed [1]; roots bind soil particles together [1]; leaf litter adds organic matter to hold soil [1].
(c) (ii) Adds organic matter/humus [1]; improves soil crumb structure/aeration [1]; increases water-holding capacity / feeds beneficial soil decomposers [1].
(d) (i) Water delivered directly to roots [1]; less water lost to evaporation [1]; prevents surface runoff/erosion [1].
(d) (ii) Any two from: reduced river flow/recharge from glaciers; increased evaporation due to higher temperatures; changing rainfall patterns/more frequent droughts [2].

Question 3 · Theory

26 marks

Managing the Impact of Rock Extraction and Renewable Energy in Taupō, New Zealand

The Taupō region is characterized by unique volcanic geology, which provides opportunities for geothermal energy but also attracts mining interest.

(a) (i) Distinguish between open-pit (surface) mining and sub-surface mining in terms of environmental impact. [3]
(ii) Describe three methods used to restore a mine site after open-pit mining has ended. [3]

(b) A mining company proposes to build a new gold processing facility near Taupō.
(i) State why an Environmental Impact Assessment (EIA) must be conducted before a mining license is granted. [2]
(ii) Suggest three potential negative impacts of the gold processing facility on the local community. [3]

(c) The Taupō region has significant geothermal energy resources. The table shows the electricity generation by source in New Zealand for 2022:
- Hydroelectric: 60%
- Geothermal: 18%
- Wind: 7%
- Natural Gas: 10%
- Coal: 3%
- Other (solar, biomass): 2%

(i) Describe how a researcher would construct a bar chart to represent these data, detailing the axis labels, scale selection, and plotting. [4]
(ii) Suggest why geothermal energy is considered a reliable 'baseload' power source compared to wind power. [2]
(iii) Explain how geothermal energy extraction can have localized environmental impacts. [3]

(d) Some environmentalists argue that New Zealand should phase out fossil fuels entirely.
(i) Calculate the total percentage of electricity generated from non-renewable sources in New Zealand in 2022 using the data provided. [2]
(ii) To what extent do you agree with the statement: "Relying 100% on renewable energy for electricity is achievable for all countries"? Give reasons for your answer. [4]

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Worked solution

(a) (i) Open-pit mining removes large amounts of overburden, destroying all surface vegetation and habitats, and creating massive visual scars. Sub-surface mining has a much smaller surface footprint but can lead to ground subsidence and deep aquifer contamination. (ii) Backfilling the pit with waste rock, spreading stored topsoil and replanting native vegetation, or flooding the pit to create a recreational lake/wetland. (b) (i) To identify potential environmental damage before it occurs and to outline mitigation plans to protect local ecosystems. (ii) Toxic chemical spills (e.g., cyanide used in gold extraction), noise pollution from heavy machinery, and increased heavy vehicle traffic. (c) (i) The x-axis is labeled 'Energy Source' (categories: Hydro, Geothermal, Wind, Gas, Coal, Other), and the y-axis is labeled 'Percentage of electricity generated / %' (scale from 0 to 60, with 10% intervals). Bars should be of equal width with gaps between them. (ii) Geothermal energy is available 24/7 regardless of weather conditions, whereas wind power is intermittent and dependent on wind speed. (iii) It can cause land subsidence as fluids are extracted, release trace greenhouse gases (like carbon dioxide and hydrogen sulfide), and discharge hot, mineral-rich wastewater into local ecosystems if not reinjected. (d) (i) Non-renewable sources: Natural Gas (10%) + Coal (3%) = 13%. (ii) I agree to some extent. Countries with abundant geothermal, wind, solar, or hydro resources (like New Zealand) can achieve high renewable percentages. However, many landlocked or fossil-fuel-dependent countries face high infrastructure costs, lack of geographical resources, and need reliable battery storage technology to manage intermittent renewables, making 100% renewable electricity difficult to achieve immediately.

Marking scheme

(a) (i) Open-pit has greater habitat destruction/deforestation [1]; open-pit causes severe visual pollution/landscape scarring [1]; sub-surface has smaller surface area but risks underground water contamination/subsidence [1].
(a) (ii) Any three from: backfilling the pit; contouring the land to match surroundings; spreading topsoil; revegetation/planting native species; bioremediation of toxic soils; creating a lake/wetland [3].
(b) (i) Identify environmental impacts/hazards before project begins [1]; suggest mitigation strategies/conditions to minimize damage [1].
(b) (ii) Any three from: toxic chemical leaks (e.g. cyanide); dust/air pollution; noise pollution; visual impact; traffic congestion; loss of property value [3].
(c) (i) Clear label on both axes with unit on y-axis (%) [1]; appropriate scale occupying >50% of the grid [1]; all 6 bars plotted accurately [1]; bars of equal width with clear spaces between them [1].
(c) (ii) Continuous/constant generation [1]; not dependent on weather/climatic variables [1].
(c) (iii) Any three from: land subsidence/sinkholes; thermal pollution of local waterways; release of sulfur dioxide/hydrogen sulfide/CO2; contamination of local groundwater with heavy metals [3].
(d) (i) Correct identification of fossil fuels (Gas + Coal) [1]; calculation: 10% + 3% = 13% [1].
(d) (ii) Max [4] marks. Balanced argument: achievable for countries with strong geographical potential (e.g. hydro, solar, geothermal) [1]; difficult for countries lacking these resources [1]; challenge of intermittency requires massive battery storage infrastructure [1]; high initial capital cost for developing countries [1].

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