Cambridge IGCSE Environmental Management 0680 — 2023 Oct/Nov Paper 2 · Variant 2

1 Halley is a British scientific research station in Antarctica. Halley is built on a floating ice shelf in the Weddell Sea. The ice shelf is 150 m thick. (a) 11% of the area of Antarctica is floating ice shelves. Calculate the area of Antarctica that is floating ice shelves. Give your answer to one decimal place. ........................................ million km2 [2] (b) The table shows temperature data for Halley. month minimum maximum average temperature / °C temperature / °C temperature / °C Jan –6.6 –2.5 –4.6 Feb –15.2 –6.5 –10.0 Mar –21.5 –10.3 –16.5 Apr –29.2 –14.5 –21.7 May –32.3 –16.4 –24.9 Jun –32.5 –19.6 –26.9 Jul –35.4 –22.7 –28.8 Aug –36.7 –19.9 –28.4 Sep –33.3 –16.7 –26.4 Oct –24.9 –14.1 –19.7 Nov –16.0 –8.5 –11.6 Dec –8.2 –3.5 –5.3 (i) Calculate the annual range in minimum temperature for Halley. ..................................................... °C [2] (ii) October to February are summer months in Antarctica. Plot a line graph of the average temperature for these summer months. [4] (iii) Explain why it is not possible to grow crops at Halley. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [4] (c) Halley is built on an ice shelf that moves 400 m further into the Weddell Sea every year. The depth of the ice at Halley increases by 1 m every year. The diagram shows part of the living accommodation at Halley. adjustable legs metal skis level of ice The accommodation is built on giant metal skis, with adjustable legs. Previous research stations were built on fixed legs that were buried in the ice sheet. (i) Suggest reasons why Halley is built on giant metal skis, with legs that can be adjusted. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [4] (ii) The accommodation is built using insulating material that is very good at reducing heat loss. Suggest two reasons why this is important at Halley. 1 ........................................................................................................................................ ........................................................................................................................................... 2 ........................................................................................................................................ ........................................................................................................................................... [2] (d) The waste management policy at Halley is to: • minimise the quantity of waste produced • reuse and recycle • remove all waste from Antarctica, apart from sewage and food waste. (i) Suggest reasons why it is important to minimise the quantity of waste produced at Halley. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (ii) Suggest why sewage and food waste are not removed from Antarctica. ........................................................................................................................................... ..................................................................................................................................... [1] (e) Sewage and food waste at Halley can be treated using a bioreactor. A bioreactor contains microorganisms. The diagram shows a bioreactor. gas in pressure release outlet sewage, food waste and microorganisms heated layer waste sewage sludge (i) The microorganisms in the bioreactor respire. State the name of the gas needed for the microorganisms to respire. ..................................................................................................................................... [1] (ii) Suggest one reason why pressure builds up in the bioreactor. ........................................................................................................................................... ..................................................................................................................................... [1] (iii) The microorganisms need an optimum temperature to work correctly. Temperature is an abiotic component in an ecosystem. State three other abiotic components in an ecosystem. 1 ........................................................................................................................................ 2 ........................................................................................................................................ 3 ........................................................................................................................................ [3] (iv) Waste sewage sludge can be dried and burnt. The ash produced can be collected. Suggest one environmental impact of burning waste sewage sludge. ........................................................................................................................................... ..................................................................................................................................... [1] (v) In many countries, waste sewage sludge is spread onto fields. Suggest one benefit of this practice to farmers. ........................................................................................................................................... ..................................................................................................................................... [1] (vi) Bioreactors are used to produce biofuels. Biofuels are a renewable energy resource. State two other renewable energy resources. 1 ........................................................................................................................................ 2 ........................................................................................................................................ [2] [Total: 30]

Mark scheme: Question Answer Marks 1(a) 14.2  0.11 or 1.562; 2 1.6; 1(b)(i) –36.7 AND –6.6; 2 30.1; 1(b)(ii) axes labelled with unit: x-axis (month and) Oct Nov Dec Jan Feb and y-axis (average) temperature and C; 4 sensible linear scale such that the data occupies half the grid area; data plotted correctly for Oct to Feb; plots connected with line or smooth curve; 1(b)(iii) any four from: 4 lack of sunlight; (extreme) cold; no, rain / precipitation; water trapped as ice / no available water; prevents photosynthesis; built on ice / no soil / ground frozen; 1(c)(i) any four from: 4 easily moved; height above ice can be increased; legs can be removed / stops it getting buried / stops legs getting stuck / reduces land pollution; increases surface area / stops sinking; idea of durability or strength of metal; 1(c)(ii) any two from: 2 cold temperatures / keep people warm; reducing energy use or energy resources / increased efficiency ; all energy resources must be brought in; (in cold) machinery stops working; 1(d)(i) any two from large amounts are: 2 costly to remove; difficult to store / reduces quantity to store; difficult to transport; less energy needed to remove the waste; prevents, visual /smell / water / atmospheric pollution; 1(d)(ii) any one from: 1 large amounts / difficult to transport / long distance to transport; idea that transportation increases risk of disease or water pollution; smell; 1(e)(i) oxygen; 1 1(e)(ii) carbon dioxide / gas (is produced); 1 1(e)(iii) any three from: 3 humidity / water; oxygen; salinity; light; pH; 1(e)(iv) any one from: 1 carbon dioxide / greenhouse gases, released; global warming / climate change; smell; 1(e)(v) any one from: 1 increases soil fertility / adds, nutrients or organic matter, to soil; (organic) fertiliser; increases crop yield; 1(e)(vi) any two from: 2 geothermal; hydro(electric) / HEP; tidal; wave; solar; wind;

2 A fact sheet about South Georgia is shown. South Georgia is an island in the Southern Ocean near Antarctica. 88% of the species in the Southern Ocean are found nowhere else on Earth. The island has an area of 3903 km2 and a population of 30 scientists and support staff. Tourists also visit the island. There are no trees or bushes. Birds nest on the ground. The land is often covered with snow and some areas have permanent glaciers. Rats were accidentally introduced to the island by whale hunters 200 years ago. The rats ate the eggs and chicks of seabirds. They threatened the pipit bird and the brown duck with extinction. (a) A rat-removal programme began in 2010. (i) Suggest reasons why rats needed to be removed from South Georgia. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (ii) A total of 300 tonnes of poisoned rat food were dropped on the island from the air over five years as part of the removal programme. Suggest why some scientists were concerned about this method of rat removal. ........................................................................................................................................... ..................................................................................................................................... [1] (b) In 2018, South Georgia Island was declared rat free. (i) Strategies are used to keep South Georgia Island rat free. They include: • keeping large tourist boats offshore • moving people to the island in smaller boats. Suggest how these strategies help to keep the island rat free. ........................................................................................................................................... ..................................................................................................................................... [1] (ii) After the poisoned rat food was dropped, two methods were used to find out if all the rats were removed. method 1: Three dogs were walked 2500 km around the island. The dogs were trained to identify rats by their smell. method 2: Thousands of chew sticks were installed around the island to detect signs of rat teeth-marks. Suggest limitations for each method. method 1 ........................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... method 2 ........................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... [3] (c) New Zealand consists of about 600 islands. It has a total area of 268 021 km2 and a population of approximately five million people. New Zealand plans to remove all their rats by 2050. Suggest reasons why the removal programme will be more difficult in New Zealand than on South Georgia. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [3] (d) Rats can spread bacterial diseases if their urine gets into drinking water. State two strategies to treat water that contains bacteria to make it safe to drink. 1 ................................................................................................................................................ 2 ................................................................................................................................................ [2] [Total: 12]

Mark scheme: 2(a)(i) any two from: 2 competition / outcompeting (native species); no natural predator; predators (to native species) / endanger populations (of native species); idea of ease of predation, e.g. eat nesting birds as no groundcover; 2(a)(ii) any one from: 1 can kill non-target species / other species eat rat poison; poison can enter water sources; 2(b)(i) any one from rats in small boats: 1 can’t hide; easier to see; easier to remove; 2(b)(ii) overall max three: 3 max two for dogs method 1: only walked part of the island / 3 dogs can’t cover all island; dogs might miss a rat / can’t smell them over a long distance / rats move around; dogs can only work for a limited period of time; cold weather conditions for dogs; max two for chew sticks method 2: costly, as thousands needed; time consuming / need to be inspected for chew marks other animals might chew them / difficult to interpret type of chew marks; rats may not use chew stick / chew stick not in area where rats are; same rat may have chewed on different sticks; chew sticks might get buried (by snow); 2(c) any three from in New Zealand: 3 larger area of land / more islands; people live there; trees / ground cover (for rats to hide); people may protest / concern over harm to people; more food sources; more people or ships arriving or leaving; 2(d) boiling; 2 chlorination;

3 Patagonian toothfish are found in the Southern Ocean. The fish grow slowly. It is 10 years before they become adult fish. They can live for up to 50 years. The fish can sell for $140 for 1 kg of fish. 2 m (a) Illegal fishing of the Patagonian toothfish occurs. This fishing is unsustainable. Explain what is meant by unsustainable fishing. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [2] (b) The graph shows the mass of total reported legal catch, estimated illegal catch and total estimated catch for Patagonian toothfish for a four-year period. Key estimated illegal catch total reported legal catch total estimated catch 120 000 100 000 80 000 mass 60 000 / tonnes 40 000 20 000 0 1 2 3 4 year (i) Calculate the mass of the total estimated catch for year 1. .............................................. tonnes [1] (ii) Suggest reasons why there is a large trade in illegal fishing of the Patagonian toothfish. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] (iii) State three ways the harvesting of marine species in the Southern Ocean can be managed. 1 ........................................................................................................................................ 2 ........................................................................................................................................ 3 ........................................................................................................................................ [3] (c) A food chain for the Patagonian toothfish is shown. phytoplankton krill squid Patagonian toothfish There are about 450 million tonnes of krill in the Southern Ocean. A report states that climate change could reduce the size of the krill population by up to 40%. (i) Suggest one impact on the population of Patagonian toothfish if the krill population is reduced. Give a reason for your answer. impact ................................................................................................................................ reason ............................................................................................................................... [1] (ii) Suggest reasons why climate change could reduce the size of the krill population. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] [Total: 12]

Mark scheme: 3(a) any two from: 2 fished at a greater rate than population can recover; eventually stocks run out / fish unavailable for future generations; young fish are caught / reproduction cannot occur; 3(b)(i) 104 000; 1 3(b)(ii) any three from: 3 difficult to patrol or monitor (fishing boats as ocean is large); worth a lot of money; so fishermen do not want to throw back; easily caught in nets / easily caught as bycatch; 3(b)(iii) any three from: 3 use smaller nets; use larger mesh size; limit size of boats; quotas / limit number of boats / licences; closed seasons; protected areas / reserves / no fish zones; laws / international agreements / legislation; monitoring / patrols; fines / enforcement; 3(c)(i) any one from: 1 (fish) population decrease and fewer squid or less food to eat; no effect and find a different food source; 3(c)(ii) any two from: 2 water too warm; change in ocean circulation; change in predators; change in availability of, food / phytoplankton / nutrients;

4 Snow builds up in layers in Antarctica every year. Over time, the buried snow is compressed by the weight of the snow above it. This forms layers of ice. Chemicals in the atmosphere are captured by falling snow and become part of the ice. Bubbles of air are also trapped in the ice layers. Samples of ice are taken by drilling down into the ice layers to remove ice cores. The photograph shows layers of ice in part of an ice core. youngest ice layer at top of ice core older ice layer deeper down the ice core (a) Ice cores are cut into thin slices and each slice is analysed to investigate the climate in the past. (i) Suggest why thin slices of an ice core are individually analysed rather than the whole length of the ice core. ........................................................................................................................................... ..................................................................................................................................... [1] (ii) Suggest how major volcanic eruptions are used to determine the age of a slice of an ice core. ........................................................................................................................................... ..................................................................................................................................... [1] (b) The graph shows data obtained from an ice core for the concentration of carbon dioxide in the atmosphere from 1760 to 2000. 370 360 350 340 330 concentration of CO2 320 / parts per million (ppm) 310 300 290 280 270 1760 1780 1800 1820 1840 1860 1880 1900 1920 1940 1960 1980 2000 year (i) Describe the trend shown by the graph. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (ii) Suggest reasons for the trend shown by the data. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (iii) Carbon dioxide is a greenhouse gas that is used to give information on climate change. State the names of two other greenhouse gases. 1 ........................................................................................................................................ 2 ........................................................................................................................................ [2] (iv) Explain why climate change is causing sea levels to rise. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] (c) The ozone hole is an area of depleted ozone in the atmosphere over Antarctica. It was discovered by Antarctic scientists in 1985. (i) Name the chemicals responsible for ozone depletion. ..................................................................................................................................... [1] (ii) Name the layer of the atmosphere where ozone depletion occurs. ..................................................................................................................................... [1] (iii) Explain why ozone depletion is a concern. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] [Total: 16]

Mark scheme: 4(a)(i) any one from: 1 individual years can be identified; each slice represents a different time period; 4(a)(ii) any one from: 1 idea that we know when the volcano occurred, so we know the age of the layer which contains ash; chemical evidence of the volcanic eruption (in the ice); 4(b)(i) increasing (CO2 concentration over time); 2 at faster rate / steeper gradient (in recent years); 4(b)(ii) any two from: 2 (use or combustion of) fossil fuels increased; increased population; increased, industrialisation / urbanisation / use of vehicles; deforestation; 4(b)(iii) any two from: 2 methane; water (vapour); AVP;; 4(b)(iv) melting, ice / ice sheets / glaciers / permafrost; 3 water in the seas is warming (due to atmospheric warming); causing: volume of water in seas or oceans expands; 4(c)(i) CFC(s) / chlorofluorocarbons; 1 4(c)(ii) stratosphere; 1 4(c)(iii) higher levels of, UV / ultraviolet radiation (reach Earth); 3 causing any two from: skin cancer; cataracts; damage to vegetation;

5 (a) Tourism to Antarctica is increasing. (i) In 2016, there were 43 915 Antarctic tourists. In 2017, this increased to 51 707. Calculate the percentage increase in tourist numbers. .......................................................% [2] (ii) Tourists travel to Antarctica by ship. They visit for one to three hours each day in groups of less than 100. They must be supervised by experts on Antarctic wildlife. Suggest how this strategy limits the impact of tourism on Antarctic wildlife. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (b) In 2009, large ships carrying tourists were banned from Antarctic waters. This was to reduce the risk of an oil spill from the ships. (i) Explain how a double-hulled ship can reduce the risk of an oil spill. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (ii) State one strategy for dealing with an oil spill. ..................................................................................................................................... [1] (c) Describe the impacts of an oil spill on marine mammals. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] [Total: 10]

Mark scheme: 5(a)(i) 51 707 − 43 915 or 7792; 2 17.7(43) / 18; 5(a)(ii) any two from: 2 prevents tourists feeding animals / touching animals / making noises / dropping litter / less waste; prevents disturbance of, breeding / feeding; educate the tourists about Antarctica; 5(b)(i) idea that: 2 outer / first, hull damaged; inner / second, hull prevents the oil entering the ocean; 5(b)(ii) boom / detergent (sprays) / skimmers; 1 5(c) any three from: 3 oil coats fur / skin; destroys insulating ability of fur; leads to hypothermia; oil ingested / taken in during feeding or when cleaning; toxic; bioaccumulation; oil inhaled / suffocation; oil gets in eyes; reduction in food;