Climate change — Paper 2 · A Level Environmental Management (AS only) 8291

4 Fig. 4.1 is a series of photographs showing changes in the Grinnell Glacier, Montana, USA, between the years 1938 and 1998. 1938 1981 1998 Fig. 4.1 (a) Suggest how human activities might have led to the loss of the ice store shown in Fig. 4.1. [10] (b) Assess the impact of international protocols on the loss of natural water stores. Describe the difficulties in achieving such agreements. [30] [Total: 40]

40 marks

Mark scheme: 4(a) Global warming leading to climate change, resulting in an increase in average yearly temperatures, which has led to loss of ice over the decades and the glacier retreating. Melting rate has increased in recent years. Shrinking size of lake at foot of glacier. Some reference to increase in open water as ice retreats from the lake. Linked to human activities such as deforestation, increased burning of fossil fuels especially in vehicles, decomposition in landfills increasing, increased agriculture. Pollution from soot deposits from vehicles has reduced the reflective nature of the ice making melting more likely. Some mention of erosion due to tourist / climbing activity is relevant Please use level descriptors 1 10 4(b) The question requirements are: • To show understanding of the causes of water store loss • To explain the range of different water stores and how they are affected • To explain the problems in reaching international agreements Water stores are lost because of climate change leading to melting of glaciers, reduced precipitation preventing groundwater and aquifers from replenishing and deforestation increasing run-off and flooding. Increasing population also leads to reduction through over-use, increased demand and waste. Human activity pollutes the water stores. Pollution crosses international boundaries and so do water resources such as rivers. Consequently, internationally agreed protocols are vital to begin reducing the rate of water loss and begin the reversal process. Political, financial and water-wealth issues affect the chances of reaching agreement. These include the demands of rising populations, industrial development, territorial ambitions and the availability of potable water. Reference to existing international protocols aimed at reducing emissions and rein in climate change. Description of the difficulties in obtaining agreements and comment on potential effects if able to reduce loss of water stores Please use level descriptors 2 30

This question in 8291/21 May/June 2019

1 (a) Fig. 1.1 shows part of a local hydrological cycle before and after urban development. X runoff precipitation Diagram A: infiltration before urban development interception X runoff precipitation Diagram B: infiltration after urban development interception Key = movement of water width of arrow = relative volume of water Fig. 1.1 (i) Name the process labelled X in Fig. 1.1. … [1] (ii) Describe two changes in the movement of water after urban development shown in Fig. 1.1. … … … … [2] (iii) Explain how urban development may cause rivers to flood. … … … … … … … … [4] (b) Fig. 1.2 shows the severity of drought in areas of the USA for two different years. January 12, 2010 N January 10, 2017 Key abnormally dry moderate drought severe drought extreme drought exceptional drought Fig. 1.2 (i) State three differences in the drought conditions in the USA between 2010 and 2017 shown in Fig. 1.2. … … … … … … [3] (ii) Explain how changes in the hydrological cycle can lead to the development of drought conditions. … … … … … … … … [4] (iii) Describe strategies to manage the sustainable supply of water for domestic, industrial and agricultural use. … … … … … … … … … … … … [6] [Total: 20]

20 marks

Mark scheme: 1(a)(i) (evapo)transpiration 1 1(a)(ii) increased surface run-off; reduced (evapo)transpiration; reduced interception; reduced infiltration; max 2 1(a)(iii) increased building / infrastructure (using non-porous materials); reduces absorption / increases surface run-off; loss of trees; reduces evapotranspiration; less roots to slow the movement of water; greater volume of water enters rivers; more rapidly; increased amount raises river level too rapidly; max 4 1(b)(i) January 10th, 2017: there are more areas experiencing drought conditions; the drought areas are more widespread across the states; drought conditions are moving eastwards; drought conditions have spread south; there are more areas with the most extreme droughts; the area with the most extreme drought in 2010 is no longer experiencing that; max 3 1(b)(ii) patterns in local climate change; precipitation decreases; storm tracks change; increased temperatures; increase evaporation; max 4 Question Answer Marks 1(b)(iii) uses of natural supplies and new technologies; storing runoff in reservoirs; diverting flows from water-abundant to water-scarce regions; extracting aquifer resources; water reuse / use of grey water; desalination; rainwater harvesting; reducing high losses / waste from water supply distribution systems / households; education; max 6

This question in 8291/22 May/June 2019

1 (a) Fig. 1.1 shows part of a local hydrological cycle before and after urban development. X runoff precipitation Diagram A: infiltration before urban development interception X runoff precipitation Diagram B: infiltration after urban development interception Key = movement of water width of arrow = relative volume of water Fig. 1.1 (i) Name the process labelled X in Fig. 1.1. … [1] (ii) Describe two changes in the movement of water after urban development shown in Fig. 1.1. … … … … [2] (iii) Explain how urban development may cause rivers to flood. … … … … … … … … [4] (b) Fig. 1.2 shows the severity of drought in areas of the USA for two different years. January 12, 2010 N January 10, 2017 Key abnormally dry moderate drought severe drought extreme drought exceptional drought Fig. 1.2 (i) State three differences in the drought conditions in the USA between 2010 and 2017 shown in Fig. 1.2. … … … … … … [3] (ii) Explain how changes in the hydrological cycle can lead to the development of drought conditions. … … … … … … … … [4] (iii) Describe strategies to manage the sustainable supply of water for domestic, industrial and agricultural use. … … … … … … … … … … … … [6] [Total: 20]

20 marks

Mark scheme: 1(a)(i) (evapo)transpiration 1 1(a)(ii) increased surface run-off; reduced (evapo)transpiration; reduced interception; reduced infiltration; max 2 1(a)(iii) increased building / infrastructure (using non-porous materials); reduces absorption / increases surface run-off; loss of trees; reduces evapotranspiration; less roots to slow the movement of water; greater volume of water enters rivers; more rapidly; increased amount raises river level too rapidly; max 4 1(b)(i) January 10th, 2017: there are more areas experiencing drought conditions; the drought areas are more widespread across the states; drought conditions are moving eastwards; drought conditions have spread south; there are more areas with the most extreme droughts; the area with the most extreme drought in 2010 is no longer experiencing that; max 3 1(b)(ii) patterns in local climate change; precipitation decreases; storm tracks change; increased temperatures; increase evaporation; max 4 Question Answer Marks 1(b)(iii) uses of natural supplies and new technologies; storing runoff in reservoirs; diverting flows from water-abundant to water-scarce regions; extracting aquifer resources; water reuse / use of grey water; desalination; rainwater harvesting; reducing high losses / waste from water supply distribution systems / households; education; max 6

This question in 8291/23 May/June 2019

2 (a) Fig. 2.1 shows the flows and stores of water in the global hydrological cycle. A number is given to indicate the amount of water within each flow or store. atmosphere 12.7 ocean to land water vapour transport 40 ocean ocean land evapotrans- precipitation evaporation precipitation piration 373 413 113 73 ocean 1 335 040 rivers, lakes riverriver flowflow ice glaciers 26 350 178 3838 infiltration soil moisture 122 percolation ground water flow 2 ground water 15 300 permafrost 22 Key direction of flow store / arbitrary units Fig. 2.1 (i) State where most of the water that has evaporated from the oceans falls as precipitation shown in Fig. 2.1. … [1] (ii) Calculate the total amount of stored water in Fig. 2.1. … arbitrary units [2] (iii) The global hydrological cycle is a closed system. Explain reasons why a local hydrological cycle, such as in a drainage basin, can not be described as a closed system. … … … … … … … … [4] (iv) Describe two ways in which human activities can affect a local hydrological cycle. … … … … … … … … [4] (b) Fig. 2.2 is a map showing the predicted loss of land to the sea as a result of a rise in sea levels of 3 metres in Florida, United States of America. N Atlantic Ocean DaytonaDaytona BeachBeach StSt PetersburgPetersburg WestWest PalmPalm BeachBeach Key Gulf predicted land of MiamiMiami lost to the sea Mexico BeachBeach land predicted to remain above water water Fig. 2.2 (i) Suggest causes for the predicted rise in sea levels shown in Fig. 2.2. … … … … … … … … [4] (ii) Describe strategies that could be used to manage the effects of coastal inundation caused by a rise in sea level of 3 metres, such as that shown in Fig. 2.2. … … … … … … … … … … [5] [Total: 20]

20 marks

Mark scheme: 2(a)(i) ocean; 1 2(a)(ii) 1 377 024.7(arbitrary units); correct working ; 2 2(a)(iii) closed system does not lose water; local hydrological cycle loses / gains water; run-off into rivers; flows away from the region; groundwater can flow into rivers; water evaporates and can be blown away by winds; animals can migrate away from the region; effects of storms / climate change; max 4 4 2(a)(iv) increased carbon emissions; lead to climate change; weather patterns change; agricultural practices change evapotranspiration rates; drainage of land; increased urbanisation increases run-off; increased industrial / domestic use / overuse of boreholes and aquifers reduces stores; building of dams for reservoirs / HEP; leads to increased evaporation; max 4 4 2(b)(i) Increased carbon dioxide / methane emissions; lead to global warming / climate change; because heat is trapped / reflected back to Earth; increased melting of arctic ice / glaciers; increases volume of water in oceans / seas; max 4 4 Question Answer Marks 2(b)(ii) reduce emissions of carbon dioxide / methane; example e.g. factory scrubbers / catalytic converters / electric cars; move away from fossil fuels; increase reliance on renewable energy forms; named example; traffic management schemes / car pool / public transport; improve coastal defences; prepare / educate population; build levees / dykes; treat increased salinity of coastal soils to sustain agriculture; max 5 5

This question in 8291/22 Oct/Nov 2019

2 (a) Fig. 2.1 is a graph showing the demand for water by sector in China for 2005, 2015 and predicted demand for 2030. Key domestic industry 818 agriculture 133133 667 8888 555 265265 6868 194194 annual water 129129 usage billion m3 420420 358358 385385 2005 2015 2030 year Fig. 2.1 (i) State the sector shown in Fig. 2.1 which is predicted to have the largest increase in demand for water from 2005 to 2030. … [1] (ii) Suggest reasons for the increase in demand for water by the sector stated in (a)(i). … … … … … … [2] (iii) Describe four ways China might manage the increase in demand for water shown in Fig. 2.1. … … … … … … … … [4] (iv) Fig. 2.2 shows how the predicted demand for water will affect the water supply in different regions of China in 2030. Key surplus supply moderate shortage severe shortage Song Northwest Huang Liao Hai Huai Southwest Pearl Yangtze Southeast Fig. 2.2 Describe the impact of the predicted 2030 water supply for the Yangtze region of China. … … … … … … … … [4] (b) Fig. 2.3 is an extract from an English-language webpage published in China. Jade Dragon Snow Mountain Shrinks The melting of the glaciers at Jade Dragon Snow Mountain, in Lijiang city of China’s southwest Province, has accelerated. Fig. 2.3 (i) Suggest one reason for the accelerated melting of the glaciers described in Fig. 2.3. Explain your answer. … … … … [2] (ii) Glaciers and ice caps store more than 68% of the Earth’s freshwater. Describe three impacts of glaciers melting. … … … … … … [3] (c) Describe the impacts of pollution due to human activity on a named water store. Include the source of this pollution in your answer. … … … … … … … … [4] [Total: 20]

20 marks

Mark scheme: 2(a)(i) industry; 1 2(a)(ii) growing population; greater consumer demands; increasing industrialisation; growing economy; increasing manufacture for export; max 2 2(a)(iii) build reservoirs; use desalination methods; improve infrastructure; establish water grid system to move water to places in need; import water; reduce waste; education; max 4 2(a)(iv) severe shortage predicted; domestic use affected; (less) for drinking / washing / valid example; Industrial use affected; (less) for use in cooling / manufacturing processes / valid example; Agricultural use affected; (less) for watering crops / livestock / valid example; max 4 2(b)(i) increased release of greenhouse gases; accumulate in upper atmosphere; absorb infra-red / heat; emitted back to Earth; increasing temperatures; max 2 Question Answer Marks 2(b)(ii) affect the supply of drinking water / irrigation water; could lead to drought conditions; due to loss of annual melt flow; leads to rising sea levels; coastal and low-lying areas at risk; loss of reflective areas / decrease in albedo affects global temperatures; contributing to global warming; max 3 2(b)(c) named pollutant e.g. fertiliser / nutrient enrichment / sewage / named chemical; relevant method of pollution e.g. farming run-off / sewage pipes into the sea / chemical spills; relevant environmental impact or impacts; relevant health impact or impacts; 4

This question in 8291/21 May/June 2020

4 Fig. 4.1 is a graph of average Arctic sea ice extent for March each year from 1979 – 2019. 17.0 16.5 16.0 average sea ice 15.5 extent / millions km2 15.0 14.5 14.0 1980 1984 1988 1992 1996 2000 2004 2008 2012 2016 2020 year Fig. 4.1 (a) Describe and explain the changes in Arctic sea ice extent shown in Fig. 4.1. [10] (b) Using examples, evaluate the success of different international protocols in managing environmental change. [30] [Total: 40]

40 marks

Mark scheme: 4(a) Over time there is a general decrease in Arctic sea ice in March from 64 / million km2 to 14.5 / million km2 making a loss of approximately 50 / million km2. Representing a percentage loss of approximately 78%. The readings fluctuate from year to year with some significant variations (falls and rises) especially in 2004. Increasing temperatures as a result of human enhanced greenhouse effect lead to the melting of the sea ice. Gases such as carbon dioxide and methane accumulate in the atmosphere and contribute to rising temperature. Ocean temperatures are also increasing. Loss of sea ice affects the albedo further contributing to climate change. Generally decreasing. From 16.4 to 14.6 million km2. Fluctuations each year. Global warming explained. Fluctuations due to seasonal variations. 4(b) The question requirements are: • demonstrate knowledge of the international protocols • show understanding of the difficulty in achieving and monitoring the protocols • assess the relative success of chosen examples. Indicative content: Candidates should use a range of examples which could include Montreal (ozone and CFCs), Kyoto (carbon dioxide emissions) and Paris (climate change). More recent declarations are also valid. Understanding the need to reduce carbon dioxide and methane releases as well as other related policies. The difficulties in getting agreement between countries of differing levels of income, with different environmental policies and priorities, and different political ideologies as well as the problems of monitoring and enforcing these between borders and countries. Assessment of the relative success should be made. 30 please use level descriptors 1 please use level descriptors 2

This question in 8291/21 Oct/Nov 2021

4 Fig. 4.1 is a graph of average Arctic sea ice extent for March each year from 1979 – 2019. 17.0 16.5 16.0 average sea ice 15.5 extent / millions km2 15.0 14.5 14.0 1980 1984 1988 1992 1996 2000 2004 2008 2012 2016 2020 year Fig. 4.1 (a) Describe and explain the changes in Arctic sea ice extent shown in Fig. 4.1. [10] (b) Using examples, evaluate the success of different international protocols in managing environmental change. [30] [Total: 40]

40 marks

Mark scheme: 4(a) Over time there is a general decrease in Arctic sea ice in March from 64 / million km2 to 14.5 / million km2 making a loss of approximately 50 / million km2. Representing a percentage loss of approximately 78%. The readings fluctuate from year to year with some significant variations (falls and rises) especially in 2004. Increasing temperatures as a result of human enhanced greenhouse effect lead to the melting of the sea ice. Gases such as carbon dioxide and methane accumulate in the atmosphere and contribute to rising temperature. Ocean temperatures are also increasing. Loss of sea ice affects the albedo further contributing to climate change. Generally decreasing. From 16.4 to 14.6 million km2. Fluctuations each year. Global warming explained. Fluctuations due to seasonal variations. 4(b) The question requirements are: • demonstrate knowledge of the international protocols • show understanding of the difficulty in achieving and monitoring the protocols • assess the relative success of chosen examples. Indicative content: Candidates should use a range of examples which could include Montreal (ozone and CFCs), Kyoto (carbon dioxide emissions) and Paris (climate change). More recent declarations are also valid. Understanding the need to reduce carbon dioxide and methane releases as well as other related policies. The difficulties in getting agreement between countries of differing levels of income, with different environmental policies and priorities, and different political ideologies as well as the problems of monitoring and enforcing these between borders and countries. Assessment of the relative success should be made. 30 please use level descriptors 1 please use level descriptors 2

This question in 8291/23 Oct/Nov 2021

1 (a) In 2020, 83% of homes in the United Kingdom combusted natural gas (methane) for heating. In January 2020, a blend of 20% hydrogen gas and 80% natural gas was trialled in 100 homes. The trial cost more than $9 million. When hydrogen is combusted, it generates heat and water. It is estimated that switching to 100% hydrogen gas will save 6 million tonnes of carbon dioxide per year from being emitted into the atmosphere. (i) Explain why alternative fuels to methane are needed. … … … … … … [3] (ii) Suggest two reasons why the trial to replace methane might not be extended to the whole of the United Kingdom. 1 … … 2 … … [2] (iii) Hydrogen can be obtained from methane. This process emits carbon dioxide. State two strategies for removing carbon dioxide once it is in the atmosphere. 1 … … 2 … … [2] (b) Fig. 1.1 shows fossil fuel consumption as a percentage of total energy consumption for high-income economy countries (HICs) and low-income economy countries (LICs) between 1970 and 2015. 100 90 80 70 60 percentage of total energy 50 consumption 40 30 20 10 0 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 year Key HICs LICs Fig. 1.1 (i) Compare the trends shown in fossil fuel consumption for HICs and LICs shown in Fig. 1.1. … … … … … … … … [4] (ii) Some countries do not have a supply of fossil fuels. They have to import fossil fuels into their country. Explain how this can lead to energy insecurity. … … … … [2] [Total: 13]

13 marks

Mark scheme: 1(a)(i) any three from: (methane is a) greenhouse gas; (methane) contributes to climate change / global warming or described / enhanced greenhouse effect; methane has greater impact (on global warming) than CO2 / methane has higher global warming potential or higher GWP than CO2; (methane is) non-renewable / finite; (alternative source of fuel) increases energy security; non-CO2 emitting gases needed to meet carbon targets / investment in carbon neutral fuels / need to reduce carbon emissions for target / comply with international agreements; 1(a)(ii) any two from: economic reason; lack of infrastructure / may need new equipment; trial might be unsuccessful; alternative energy resources available; trial still uses, methane / greenhouse gas; people against the idea / lack of agreement / large population to convince; 2 1(a)(iii) any two from: carbon capture; named strategy; carbon, storage / sink; M2 named strategy e.g. underground, oceans, aquifers, fossil fuel seams; plant more trees / afforestation / reforestation; 2 Question Answer Marks 1(b)(i) any four comparative trends: higher or more overall consumption in HICs / HICs double; HICs starting % higher; HICs AND LICs overall decrease (from 1970–2015); HICs (steadier) decrease AND LICs fluctuates; comparative year trend or data quote from a HIC AND a LIC to support trend e.g. 1970–1985 LICs increase as HICs decrease / HIC 95(%) LIC at 33(%) in 1970 / HICs use 60–65% more / 1970–2015 or overall HICs slight fluctuation AND LICs more fluctuation; 4 1(b)(ii) any two from: economic issue; reliance on import / reliant on another country; conflict (between countries); delays or disruption in supply e.g. could be cut-of / embargo / restrictions on trade / instability in export country / natural disasters / new laws / climate change quotas; 2

This question in 8291/21 May/June 2022

2 (a) Fig. 2.1 shows a photograph of an area of densely forested land affected by human activity. Fig. 2.1 (i) Suggest reasons why there is a reduction in forest cover shown in Fig. 2.1. … … … … [2] (ii) Explain why forest fragmentation can lead to loss of biodiversity. … … … … … … [3] (b) Explain how trees absorb carbon dioxide from the atmosphere. … … … … … … [3] (c) Two types of tree, conifer and broadleaf, are considered for planting in a managed forest. The graph in Fig. 2.2 shows predicted data for the quantity of carbon stored by the two types of tree in a 50-hectare forest. The quantity of carbon stored is measured in carbon dioxide equivalent tonnes, tCO2e. 25 000 20 000 15 000 total carbon stored 10 000 / tCO2e 5 000 0 –5 000 2020 2025 2030 2035 2040 2045 2050 year Key conifer broadleaf Fig. 2.2 (i) Use Fig. 2.2 to calculate the percentage increase in quantity of carbon stored from 2020 to 2050 for conifer trees. percentage = … [2] (ii) Recommend which type of tree, conifer or broadleaf, should be planted in the managed forest. Give a reason for your answer. … … [1] (d) Table 2.1 shows historical data for forest areas planted in eight countries in 2015. Table 2.1 forest area country / million ha Brazil 8 China 79 India 12 Japan 10 Russia 20 Sweden 14 UK 3 USA 26 (i) Plot the data as a bar chart. [4] (ii) Suggest why some countries plant more trees than other countries. … … [1] [Total: 16]

16 marks

Mark scheme: 2(a)(i) any two from: 2 wood used for fuel / timber / export; increased human population; land cleared for: agriculture / mineral extraction / hydroelectric or reservoir projects / homes / buildings / roads; fire break; habitat loss; AVP; 2(a)(ii) any three from: 3 habitat loss; alters growing conditions, e.g. temperature / moisture / light / wind; increases isolation / separation between forest communities; movement of plants and animals is inhibited / some will migrate; trees are producers so less energy enters food chains; restricts breeding / gene flow; increase in invasive plants; 2(b) any three from: 3 by photosynthesis; chlorophyll (in leaves) / in chloroplasts; captures light energy / uses sunlight; carbon dioxide + water → oxygen + glucose OR 6CO2 + 6H2O → C6H12O6 + 6O2 ; 2(c)(i) M1 – 1000 − 23 000 OR 24 000; 2 ((M1  1000)  100 =) 2400; 2(c)(ii) any one from: 1 conifer AND absorbs / stores more carbon (dioxide); conifer AND grows all year round; 2(d)(i) suitable linear scale; 4 axis labels AND units; bars not touching AND of equal width; correct plotting of bars; 2(d)(ii) more land space / lower population density / more concerned about climate change / wealth / more suitable conditions / AVP; 1 grow trees for food;

This question in 8291/21 Oct/Nov 2022

4 (a) Fig. 4.1 shows the variation in minimum daily ozone over Antarctica from 1980 to 2019. 200 150 minimum daily ozone 100 / Dobson Units 50 0 1980 1985 1990 1995* 2000 2005 2010 2015 2020* * no data available year Fig. 4.1 (i) Describe the trend in minimum daily ozone over Antarctica from 1980 to 2019. … … … … … [3] (ii) Give reasons for the trend shown by the data in Fig. 4.1. … … … … [2] (iii) The ozone hole is defined as an area where the average concentration of ozone is less than 100 Dobson Units. Use the data in Fig. 4.1 to state the number of years where an ozone hole existed over Antarctica. … years [1] (iv) State two impacts of ozone depletion on human health. 1 … 2 … [2] (b) Scientists study data from Antarctic ice cores for information on climate change. Fig. 4.2 shows the estimated historic concentration of carbon dioxide in the atmosphere. 390 380 370 360 350 340 concentration of carbon dioxide 330 / ppmv 320 310 300 290 280 270 1000 1200 1400 1600 1800 2000 year Fig. 4.2 (i) Use Fig. 4.2 to describe the trend shown by the data for the concentration of carbon dioxide. … … … … [2] (ii) Mathematical models are used to predict future atmospheric concentrations of carbon dioxide. Outline the difficulties of predicting future atmospheric carbon dioxide concentrations. … … … … … … [3] (iii) Fig. 4.3 shows the estimated historic concentration of methane in the atmosphere from the year 1000 to 1600. 1800 1600 1400 1200 1000 concentration of methane 800 / ppbv 600 400 200 0 1000 1200 1400 1600 1800 2000 year Fig. 4.3 Complete Fig. 4.3 to suggest the shape of the graph for the concentration of methane from 1600 to 2000. [1] [Total: 14]

14 marks

Mark scheme: 4(a)(i) any three from: 3 high(est) 1981; low(est) 1994; (rapid) decreasing from 1981 to 1994; (from mid-1990s) plateaus; (since mid-1990s) gradual increase / fluctuates; unusually high in 2002; 4(a)(ii) any two from: 2 CFC use; reference to ozone destruction; CFC ban / phasing out; reference to CFCs staying (in stratosphere) for long time / ozone takes a long time to recover; fluctuation is part of a normal cycle; 4(a)(iii) 11; 1 4(a)(iv) any two from: 2 cataracts; skin cancer; sunburn; 4(b)(i) constant or steady concentration (of CO2) until 1800; 2 rapid increase after 1800; 4(b)(ii) any three from: 3 limited historical data (to base future predictions on); different variables used (by different models); model is only as good as the data it uses; climate feedback mechanisms are not fully understood; time delay between cause and effect; 4(b)(iii) same shape as carbon dioxide drawn; 1

This question in 8291/21 Oct/Nov 2022

2 (a) Fig. 2.1 shows a photograph of an area of densely forested land affected by human activity. Fig. 2.1 (i) Suggest reasons why there is a reduction in forest cover shown in Fig. 2.1. … … … … [2] (ii) Explain why forest fragmentation can lead to loss of biodiversity. … … … … … … [3] (b) Explain how trees absorb carbon dioxide from the atmosphere. … … … … … … [3] (c) Two types of tree, conifer and broadleaf, are considered for planting in a managed forest. The graph in Fig. 2.2 shows predicted data for the quantity of carbon stored by the two types of tree in a 50-hectare forest. The quantity of carbon stored is measured in carbon dioxide equivalent tonnes, tCO2e. 25 000 20 000 15 000 total carbon stored 10 000 / tCO2e 5 000 0 –5 000 2020 2025 2030 2035 2040 2045 2050 year Key conifer broadleaf Fig. 2.2 (i) Use Fig. 2.2 to calculate the percentage increase in quantity of carbon stored from 2020 to 2050 for conifer trees. percentage = … [2] (ii) Recommend which type of tree, conifer or broadleaf, should be planted in the managed forest. Give a reason for your answer. … … [1] (d) Table 2.1 shows historical data for forest areas planted in eight countries in 2015. Table 2.1 forest area country / million ha Brazil 8 China 79 India 12 Japan 10 Russia 20 Sweden 14 UK 3 USA 26 (i) Plot the data as a bar chart. [4] (ii) Suggest why some countries plant more trees than other countries. … … [1] [Total: 16]

16 marks

Mark scheme: 2(a)(i) any two from: 2 wood used for fuel / timber / export; increased human population; land cleared for: agriculture / mineral extraction / hydroelectric or reservoir projects / homes / buildings / roads; fire break; habitat loss; AVP; 2(a)(ii) any three from: 3 habitat loss; alters growing conditions, e.g. temperature / moisture / light / wind; increases isolation / separation between forest communities; movement of plants and animals is inhibited / some will migrate; trees are producers so less energy enters food chains; restricts breeding / gene flow; increase in invasive plants; 2(b) any three from: 3 by photosynthesis; chlorophyll (in leaves) / in chloroplasts; captures light energy / uses sunlight; carbon dioxide + water → oxygen + glucose OR 6CO2 + 6H2O → C6H12O6 + 6O2 ; 2(c)(i) M1 – 1000 − 23 000 OR 24 000; 2 ((M1  1000)  100 =) 2400; 2(c)(ii) any one from: 1 conifer AND absorbs / stores more carbon (dioxide); conifer AND grows all year round; 2(d)(i) suitable linear scale; 4 axis labels AND units; bars not touching AND of equal width; correct plotting of bars; 2(d)(ii) more land space / lower population density / more concerned about climate change / wealth / more suitable conditions / AVP; 1 grow trees for food;

This question in 8291/23 Oct/Nov 2022

4 (a) Fig. 4.1 shows the variation in minimum daily ozone over Antarctica from 1980 to 2019. 200 150 minimum daily ozone 100 / Dobson Units 50 0 1980 1985 1990 1995* 2000 2005 2010 2015 2020* * no data available year Fig. 4.1 (i) Describe the trend in minimum daily ozone over Antarctica from 1980 to 2019. … … … … … [3] (ii) Give reasons for the trend shown by the data in Fig. 4.1. … … … … [2] (iii) The ozone hole is defined as an area where the average concentration of ozone is less than 100 Dobson Units. Use the data in Fig. 4.1 to state the number of years where an ozone hole existed over Antarctica. … years [1] (iv) State two impacts of ozone depletion on human health. 1 … 2 … [2] (b) Scientists study data from Antarctic ice cores for information on climate change. Fig. 4.2 shows the estimated historic concentration of carbon dioxide in the atmosphere. 390 380 370 360 350 340 concentration of carbon dioxide 330 / ppmv 320 310 300 290 280 270 1000 1200 1400 1600 1800 2000 year Fig. 4.2 (i) Use Fig. 4.2 to describe the trend shown by the data for the concentration of carbon dioxide. … … … … [2] (ii) Mathematical models are used to predict future atmospheric concentrations of carbon dioxide. Outline the difficulties of predicting future atmospheric carbon dioxide concentrations. … … … … … … [3] (iii) Fig. 4.3 shows the estimated historic concentration of methane in the atmosphere from the year 1000 to 1600. 1800 1600 1400 1200 1000 concentration of methane 800 / ppbv 600 400 200 0 1000 1200 1400 1600 1800 2000 year Fig. 4.3 Complete Fig. 4.3 to suggest the shape of the graph for the concentration of methane from 1600 to 2000. [1] [Total: 14]

14 marks

Mark scheme: 4(a)(i) any three from: 3 high(est) 1981; low(est) 1994; (rapid) decreasing from 1981 to 1994; (from mid-1990s) plateaus; (since mid-1990s) gradual increase / fluctuates; unusually high in 2002; 4(a)(ii) any two from: 2 CFC use; reference to ozone destruction; CFC ban / phasing out; reference to CFCs staying (in stratosphere) for long time / ozone takes a long time to recover; fluctuation is part of a normal cycle; 4(a)(iii) 11; 1 4(a)(iv) any two from: 2 cataracts; skin cancer; sunburn; 4(b)(i) constant or steady concentration (of CO2) until 1800; 2 rapid increase after 1800; 4(b)(ii) any three from: 3 limited historical data (to base future predictions on); different variables used (by different models); model is only as good as the data it uses; climate feedback mechanisms are not fully understood; time delay between cause and effect; 4(b)(iii) same shape as carbon dioxide drawn; 1

This question in 8291/23 Oct/Nov 2022

1 Oil sands contain deposits of oil. Fig. 1.1 is an enlarged sketch of an oil sands sample. Each grain of sand is surrounded by a layer of water and a type of oil called bitumen. Key bitumen water sand 1 mm Fig. 1.1 (a) Oil is a fossil fuel. State two other fossil fuels. 1 … 2 … [2] (b) Extracting oil from oil sands uses large volumes of water. The waste water is stored in tailing ponds. 75% of the water in the tailing ponds is recycled back into the extraction process. (i) Suggest why the water is recycled back into the extraction process. … … … … … … [3] (ii) Suggest why some people are concerned about the storage of waste water in tailing ponds. … … … … … … [3] (c) Fig. 1.2 shows the location of oil sands deposits in Canada. These are some of the largest deposits of oil on Earth. Key N oil sands deposit river ALBERTA Edmonton Calgary Fig. 1.2 Use Fig. 1.2 to suggest the challenges of exporting oil from these oil sands locations. Give reasons for your answer. … … … … … … [3] (d) (i) Fig. 1.3 shows the oil production from oil sands and conventional oil sources in Canada from 2006 to 2019. Key oil production oil sands conventional oil sources 3.0 2.5 2.0 oil production / million barrels 1.5 per day 1.0 0.5 0.0 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 year Fig. 1.3 Use Fig. 1.3 to compare the trends in oil production from oil sands and oil production from conventional oil sources. … … … … … … [3] (ii) These oil sands deposits cover 142 200 km2. 4800 km2 of the oil sands deposits can be mined. The remaining area currently cannot be mined. Calculate the percentage of the oil sands deposits that can be mined. Give your answer to one decimal place. … % [2] (iii) Explain how a reliance on fossil fuels, such as oil, can lead to energy insecurity. … … … … [2] (e) A report stated that from 2000 to 2018 the emission rate of greenhouse gases in Canada from oil sands extraction decreased by 36%. These emissions account for 12% of Canada’s total greenhouse gas emissions. (i) Explain why greenhouse gas emissions are a concern. … … … … … … [3] (ii) Canada was one of the countries that signed the Paris Agreement in 2016. Explain why international agreements help to control greenhouse gas emissions. … … … … [2] (iii) International agreements have helped to reduce the emission rate of greenhouse gases. Suggest two other reasons why the emission rate of greenhouse gases from oil sands extraction has decreased. 1 … … 2 … … [2] (f) A pipeline for transporting oil was planned to run from Canada to the USA. Many people objected to the building of this pipeline. Suggest reasons why some people were in favour of building this pipeline. … … … … … … [3] [Total: 28]

28 marks

Mark scheme: 1(a) M1 natural gas; M2 coal; 2 1(b)(i) any three from: M1 reduce, use / wastage of water; M2 reduce risk of water insecurity; M3 reduce energy used; M4 reduce risk of energy insecurity; M5 reduce costs; 3 1(b)(ii) any three suggestions: M1 contamination of soil; M2 water pollution / pollution of named water source e.g. rivers / reservoir / drinking water supplies / groundwater; M3 (water pollution) toxic contents (to wildlife) / reduce biodiversity / disrupt food chains; M4 bioaccumulation; M5 description e.g. build up of toxins in an organism; M6 biomagnification; M7 description e.g. build up of toxins up a food chain; M8 (tail ponds) risk of collapse / flooding / stated flooding impact; 3 1(c) any three from: M1 land locked / not near a port / can’t export by sea; M2 (road transport) leads to congestion; M3 (road transport) leads to noise/visual/air, pollution or increased carbon emissions; M4 currently no pipeline; M5 (pipeline or oil spill) causes habitat / biodiversity, loss; M6 cost of oil to consumer becomes expensive / transport expensive (as remote location/transport); M7 risk of oil spills / risk of water pollution; M8 stated other negative reference to the rivers: idea of lots of rivers / surrounded by rivers / need to cross rivers / difficult to cross in winter / disruption to flow of rivers; M9 public / political, opposition; M10 idea of long distance to export country / crossing international borders; 3 Question Answer Marks 1(d)(i) any three comparisons from: M1 oil sands, starts lower / ends higher (than conventional) / ora; M2 similar trend / both have an (overall) increase; M3 oil sands increased AND conventional remains constant; M4 from 2011 oil sands increase more / ora; M5 both peak in 2019; M6 both fluctuate; M7 equal production in (end of) 2010 or 2011; M8 comparative paired quoted data; e.g. comparative, number of barrels / specific year trends 3 1(d)(ii) M1 4 800  142 200 (100) / 3.375527 / 3.376 / 3.38; M2 3.4; 2 1(d)(iii) M1 oil, is non-renewable / finite / will run out; M2 prices will increase as availability decreases / demand will be greater than supply; M3 idea of having to rely on imported fossil fuels or imported electricity / dependence on another country; 2 1(e)(i) any three from: M1 greenhouse gases absorb (infrared) radiation; M2 lead to enhanced greenhouse effect / increased global, temperatures / (global) warming; M3 causes climate change; M4 stated effect of climate change e.g. sea level rise, animal extinction / increased migration, reduction of ice sheets / wildfires / disrupt weather patterns; 3 1(e)(ii) any two from: M1 idea of, working together / global cooperation; M2 idea of, no borders in atmosphere / (greenhouse) emissions or pollutants are global; M3 finance / support, needed for LIC; M4 raises awareness; M5 incentive to follow agreement due to: financial penalties for countries who break the agreement / (international) enforcement / international standards / targets or limits or rules everyone must follow / international accountability / political or international pressure to follow the agreement; 2 Question Answer Marks 1(e)(iii) any two from: M1 improved or newer technology; M2 idea of more efficient extraction; M3 pressure from environmental groups (for emission reduction); M4 reduced extraction / limits on extraction; M5 AVP;; 2 1(f) any three from: M1 increased jobs; M2 greater availability of oil / increased energy security / more consistent supply of oil; M3 leading to lower oil prices / reduces import cost; M4 improved, local facilities / infrastructure; M5 reduces impacts of overland transport / less vehicles needed / less risk of stated pollution related to transport e.g. oil spill, air pollution, noise pollution; M6 reduces cost of transport; M7 idea of benefitting economy of country or company; 3

This question in 8291/21 May/June 2023

3 Fig. 3.1 shows a leatherback turtle. Fig. 3.1 (a) Fig. 3.2 shows the location of three populations of leatherback turtles. Key population Atlantic Eastern Pacific N Indian Tropic of Cancer Equator Tropic of Capricorn Fig. 3.2 Use Fig. 3.2 to describe the location of the population of Eastern Pacific leatherback turtles. … … … … [2] (b) Fig. 3.3 shows the mean number of turtle nests for two populations of leatherback turtles. Key population Eastern Pacific Northwest Atlantic past three turtle generations ago present measured in 2010 future predicted for year 2040 200 000 180 000 160 000 140 000 120 000 mean annual 100 000 number of nests 80 000 60 000 40 000 20 000 0 past present future time Fig. 3.3 Use Fig. 3.3 to compare the two populations of leatherback turtles. … … … … [2] (c) Climate change is a major threat to leatherback turtles. Higher sand temperature during egg incubation leads to a higher number of female turtles. (i) Explain why higher sand temperature can be a result of climate change. … … … … [2] (ii) Suggest the impact higher sand temperature has on the population of turtles. Give reasons for your answer. impact … reasons … … … [2] (iii) Suggest one other impact of climate change that could decrease the population of turtles. Give a reason for your answer. … … … … [2] (iv) Fig. 3.4 shows a turtle caught in a fishing net. Fig. 3.4 One conservation strategy for protecting turtles is reducing the accidental catch of turtles in fishing nets. Suggest how the accidental catch of turtles in fishing nets can be prevented. … … [1] (d) Captive breeding and release is another method of conserving the population of turtles. Outline the benefits and limitations of captive breeding and release. benefits … … … … limitations … … … … [4] [Total: 15]

15 marks

Mark scheme: 3(a) any two from: west coast of South America; west coast of Mexico; west coast of Central America; south tropic of Cancer; north/ south tropic of Capricorn; east Pacific Ocean; north and south of equator; 2 3(b) any two comparisons from: NW Atlantic population increasing AND E Pacific decreasing overall; past-present: NW Atlantic gradual increase AND E Pacific (gradual) decrease; present-future: sharp increase from present to future for NW Atlantic AND E Pacific (gradual) decrease; comparison of trend with both populations from past / present / future; 2 3(c)(i) any two from: more, greenhouse gases / carbon dioxide / methane in atmosphere; which absorb infrared radiation; increased (enhanced) greenhouse effect / global warming; 2 3(c)(ii) impact: (population decrease or increase) with any two valid reasons: greater number of females : males in the population; limited number of (suitable males) mates; higher temperatures may damage eggs; one male can mate with many females; 2 Question Answer Marks 3(c)(iii) any one impact and one reason: rising sea level / extreme weather; wash eggs away; habitat loss; loss of food sources; more invasive species; greater competition / predation; possible migration; ocean acidification; too acidic loss of food source of turtles; AVP; 2 3(c)(iv) any one from: legislation; use line fishing instead of nets; no fishing in areas where turtles live; education / awareness of dangers of trapping turtles in nets; 1 3(d) max [3] benefits from: no predation; diseases / illnesses can be treated; prior selection of mates; allows research of species; max [3] limitations from: expensive; difficult to support a large breeding programme; behaviour / breeding / eating pattern, of captive animals may be affected; conditions may never be suitable to release animals; eggs have to be harvested from the wild; AVP; 4

This question in 8291/22 May/June 2023

4 (a) CFCs such as CFC‑12 are not used in new equipment because of their ozone depletion potential. (i) Outline how CFCs cause ozone depletion. … … … … … … … … … … [5] (ii) Explain the meaning of the term ozone hole. … … … … [2] (b) Global warming potential (GWP) is a measure of the climate warming effect of a chemical compared to carbon dioxide. Carbon dioxide has a GWP of 1. Table 4.1 shows the GWP for chemicals used in aerosols. Table 4.1 chemical GWP CFC CFC‑12 10 900 HFC‑134a 1 430 alternative N2O (an oxide of nitrogen) 298 to CFCs HFC‑152a 124 HFO‑1234ze(E) 6 (i) Alternatives to CFCs were introduced to limit ozone depletion. Suggest other impacts associated with the use of some alternatives to CFCs. Use data from Table 4.1 to support your answer. … … … … … … … … [4] (ii) The use of CFCs was gradually phased out. Suggest reasons why a complete ban was not immediately introduced as soon as the evidence for their role in ozone depletion was understood. … … … … … … [3] [Total: 14]

14 marks

Mark scheme: 4(a)(i) any five from: CFCs are not broken down in the troposphere; CFCs move into the stratosphere; breakdown in the presence of UV light; to release a chlorine / Cl atom; rapid reactions between chlorine atoms and ozone / O3 form oxygen / O2; chlorine atoms remain in stratosphere and continue to destroy ozone; 4(a)(ii) an area (in the stratosphere) where the (average) concentration of ozone is less / depleted; than 100 Dobson units; 2 4(b)(i) max two data use from: compared to CFCs, all lower GWP / ORA; quoted data: e.g. HFC-134a is 7 times less than CFC-12; max three impacts from: contribute less to, climate change/global warming; less stated effect e.g. sea level rise; oxides of nitrogen leads to acid rain; stated effect e.g. damage crops / buildings; max [4] 4 4(b)(ii) any three from: initial evidence was not accepted / lack of initial experiment evidence; many appliances contained/used CFCs; no immediate replacement; gives time for countries to, implement ban / prepare for changes; cost implication; industry reluctance; would have led to inequality in LIC and HICs; no international agreement / Montreal agreement was not in place; AVP; 3

This question in 8291/22 May/June 2023

3 Fig. 3.1 shows a leatherback turtle. Fig. 3.1 (a) Fig. 3.2 shows the location of three populations of leatherback turtles. Key population Atlantic Eastern Pacific N Indian Tropic of Cancer Equator Tropic of Capricorn Fig. 3.2 Use Fig. 3.2 to describe the location of the population of Eastern Pacific leatherback turtles. … … … … [2] (b) Fig. 3.3 shows the mean number of turtle nests for two populations of leatherback turtles. Key population Eastern Pacific Northwest Atlantic past three turtle generations ago present measured in 2010 future predicted for year 2040 200 000 180 000 160 000 140 000 120 000 mean annual 100 000 number of nests 80 000 60 000 40 000 20 000 0 past present future time Fig. 3.3 Use Fig. 3.3 to compare the two populations of leatherback turtles. … … … … [2] (c) Climate change is a major threat to leatherback turtles. Higher sand temperature during egg incubation leads to a higher number of female turtles. (i) Explain why higher sand temperature can be a result of climate change. … … … … [2] (ii) Suggest the impact higher sand temperature has on the population of turtles. Give reasons for your answer. impact … reasons … … … [2] (iii) Suggest one other impact of climate change that could decrease the population of turtles. Give a reason for your answer. … … … … [2] (iv) Fig. 3.4 shows a turtle caught in a fishing net. Fig. 3.4 One conservation strategy for protecting turtles is reducing the accidental catch of turtles in fishing nets. Suggest how the accidental catch of turtles in fishing nets can be prevented. … … [1] (d) Captive breeding and release is another method of conserving the population of turtles. Outline the benefits and limitations of captive breeding and release. benefits … … … … limitations … … … … [4] [Total: 15]

15 marks

Mark scheme: 3(a) any two from: west coast of South America; west coast of Mexico; west coast of Central America; south tropic of Cancer; north/ south tropic of Capricorn; east Pacific Ocean; north and south of equator; 2 3(b) any two comparisons from: NW Atlantic population increasing AND E Pacific decreasing overall; past-present: NW Atlantic gradual increase AND E Pacific (gradual) decrease; present-future: sharp increase from present to future for NW Atlantic AND E Pacific (gradual) decrease; comparison of trend with both populations from past / present / future; 2 3(c)(i) any two from: more, greenhouse gases / carbon dioxide / methane in atmosphere; which absorb infrared radiation; increased (enhanced) greenhouse effect / global warming; 2 3(c)(ii) impact: (population decrease or increase) with any two valid reasons: greater number of females : males in the population; limited number of (suitable males) mates; higher temperatures may damage eggs; one male can mate with many females; 2 Question Answer Marks 3(c)(iii) any one impact and one reason: rising sea level / extreme weather; wash eggs away; habitat loss; loss of food sources; more invasive species; greater competition / predation; possible migration; ocean acidification; too acidic loss of food source of turtles; AVP; 2 3(c)(iv) any one from: legislation; use line fishing instead of nets; no fishing in areas where turtles live; education / awareness of dangers of trapping turtles in nets; 1 3(d) max [3] benefits from: no predation; diseases / illnesses can be treated; prior selection of mates; allows research of species; max [3] limitations from: expensive; difficult to support a large breeding programme; behaviour / breeding / eating pattern, of captive animals may be affected; conditions may never be suitable to release animals; eggs have to be harvested from the wild; AVP; 4

This question in 8291/23 May/June 2023

4 (a) CFCs such as CFC‑12 are not used in new equipment because of their ozone depletion potential. (i) Outline how CFCs cause ozone depletion. … … … … … … … … … … [5] (ii) Explain the meaning of the term ozone hole. … … … … [2] (b) Global warming potential (GWP) is a measure of the climate warming effect of a chemical compared to carbon dioxide. Carbon dioxide has a GWP of 1. Table 4.1 shows the GWP for chemicals used in aerosols. Table 4.1 chemical GWP CFC CFC‑12 10 900 HFC‑134a 1 430 alternative N2O (an oxide of nitrogen) 298 to CFCs HFC‑152a 124 HFO‑1234ze(E) 6 (i) Alternatives to CFCs were introduced to limit ozone depletion. Suggest other impacts associated with the use of some alternatives to CFCs. Use data from Table 4.1 to support your answer. … … … … … … … … [4] (ii) The use of CFCs was gradually phased out. Suggest reasons why a complete ban was not immediately introduced as soon as the evidence for their role in ozone depletion was understood. … … … … … … [3] [Total: 14]

14 marks

Mark scheme: 4(a)(i) any five from: CFCs are not broken down in the troposphere; CFCs move into the stratosphere; breakdown in the presence of UV light; to release a chlorine / Cl atom; rapid reactions between chlorine atoms and ozone / O3 form oxygen / O2; chlorine atoms remain in stratosphere and continue to destroy ozone; 4(a)(ii) an area (in the stratosphere) where the (average) concentration of ozone is less / depleted; than 100 Dobson units; 2 4(b)(i) max two data use from: compared to CFCs, all lower GWP / ORA; quoted data: e.g. HFC-134a is 7 times less than CFC-12; max three impacts from: contribute less to, climate change/global warming; less stated effect e.g. sea level rise; oxides of nitrogen leads to acid rain; stated effect e.g. damage crops / buildings; max [4] 4 4(b)(ii) any three from: initial evidence was not accepted / lack of initial experiment evidence; many appliances contained/used CFCs; no immediate replacement; gives time for countries to, implement ban / prepare for changes; cost implication; industry reluctance; would have led to inequality in LIC and HICs; no international agreement / Montreal agreement was not in place; AVP; 3

This question in 8291/23 May/June 2023

3 (a) Fig. 3.1 shows incoming and outgoing solar radiation. Key incoming solar radiation outgoing solar radiation Sun space reflector stratospheric aerosols high altitude stratospherestratosphere clouds tropospheretroposphere low altitude clouds land land snow and ice ocean Fig. 3.1 (i) Name the layer of the atmosphere directly above the stratosphere. … [1] (ii) Suggest why snow and ice increase surface albedo. … … [1] (iii) Some of the Sun’s energy is re-emitted back into the atmosphere as infrared radiation. Explain how some of this infrared radiation is prevented from leaving the Earth’s atmosphere. … … … … [2] (iv) Suggest how a space reflector could counteract climate change. … … … … [2] (b) Explain why eating a plant-based diet can reduce the impact of climate change. … … … … [2] (c) State the three major gases in Earth’s unpolluted atmosphere. 1 … 2 … 3 … [3] (d) Explain why international agreements are needed to control air pollution. … … … … [2] [Total: 13]

13 marks

Mark scheme: 3(a)(i) mesosphere; 1 3(a)(ii) white surfaces / snow and ice reflect (incoming) solar radiation / sunlight; 1 3(a)(iii) any two from: 2 (IR radiation) absorbed / trapped; by greenhouse gases / named gas e.g. carbon dioxide / methane / water; reflected by clouds / reflected back to surface; 3(a)(iv) any two from: 2 incoming solar radiation rays; reflect / bounce back; before it reaches Earth’s surface / before it gets trapped in atmosphere /; reduce temperature (of Earth’s surface); 3(b) any two from: 2 cattle/livestock produce methane; (produce methane which is a) greenhouse gas; livestock rearing requires more energy than growing crops; 3(c) nitrogen; 3 oxygen; carbon dioxide; 3(d) any two from: 2 air pollution knows no boundaries; carried by wind/air currents; pollution in one country effects pollution in others; reference to global issues e.g. ozone ‘hole’/climate change /acid deposition; needs co-operation between countries / countries need to work together;

This question in 8291/21 Oct/Nov 2023

3 Rice is the main food of three billion people and provides one fifth of the calories consumed globally. (a) Fig. 3.1 shows rice growing in paddy fields. Fig. 3.1 A rice paddy field is a flooded field of land with growing rice plants. This method of growing rice has been used for thousands of years. Methane and carbon dioxide are formed during this method. The annual carbon footprint of growing rice in paddy fields is equal to that of the air transport industry. (i) Suggest why some climate scientists are developing varieties of rice that do not need to be grown in paddy fields. Give reasons for your answers. … … … … … … [3] (ii) Suggest one benefit to rice farmers of growing rice in paddy fields. … … [1] (b) A farmer investigates different varieties of rice plants to compare the yield from each plant. The farmer uses this method: • select four different fields, A to D • plant a different variety of rice in each field • collect the rice crop and measure the mass of rice per hectare. Table 3.1 shows the results. Table 3.1 field mass / tonnes per ha A 4.3 B 5.7 C 0.5 D 6.0 (i) Suggest two pieces of information the farmer should record about each field for this investigation. 1 … 2 … [2] (ii) The farmer is concerned that one of the fields contains an insect pest. Suggest which field may contain an insect pest. Give a reason for your answer. field … reason … [1] (iii) The farmer uses a sweep net to survey the field for insect pests. Describe how to carry out a sweep net survey. You should include in your answer how to: • select where to survey • use a sweep net • prevent collected insects escaping. … … … … … … … … [4] (iv) Describe the limitations of using a sweep net to survey insects. … … … … [2] (v) The farmer concludes that the field contains insect pests. Outline the advantages and disadvantages of using a chemical insecticide to kill the insect pests rather than biological control. advantages … … … … disadvantages … … … … [4] (vi) The farmer groups the insect pests into four classifications and records the numbers of each insect. Table 3.2 shows the results. Table 3.2 classification of insect number of each insect, n grasshopper 167 earwig 231 aphid 48 thrips 95 Use the formula to calculate Simpson’s index of diversity, D. n 2 D = 1 – (Σ( N) ) Use the following steps: • calculate N, the total number of insects N = … n 2 • calculate for each classification ( N) grasshopper = … earwig = … aphid = … thrips = … n 2 • calculate Σ( N) n 2 = … Σ( N) • calculate D. D = … [4] [Total: 21]

21 marks

Mark scheme: 3(a)(i) any three from: 3 methane / carbon dioxide, are greenhouse gases; leads to, global warming / climate change; (growing new varieties) reduces carbon footprint; rice eaten by very large number of people / rice is a staple food; (growing new varieties) mean less water used / increases water security; 3(a)(ii) any one from: 1 no need to irrigate; farmers familiar with this method / traditional method; terracing prevents soil erosion; can be grown on limited / poor quality soil; water contains nutrients; high yield (per unit area); 3(b)(i) any two from: 2 size / area (of field); soil type; soil pH; moisture content of field; salinity / soil fertility; 3(b)(ii) C AND lowest yield / mass per ha; 1 3(b)(iii) total max four: 4 any one from: random sampling described: sample sites selected using grid and use a random number generator; OR systematic sampling described: divide the field into grid / transects and select every nth square / transect; any two from: method of sweeping: walk slowly up/down rows or across field; sweep from side to side / sweep through 180; use one sweep per step; avoid thorns/sharp bushes; sweep upper part of plant; count the number of insects / average number of insects; any one from: method of stopping insects escaping: turn the net so opening is face down / hold net closed above contents; let bottom of net drape over edge of a frame (to trap insects in net); 3(b)(iv) any two from: 2 some insects, missed / escape; insects missed close to, soil / ground; difficult to use in, water / paddy field; does not work well in short or dense vegetation; net is easily damaged; time consuming / hard work; 3(b)(v) total max four: 4 max [3] advantages: effective / efficient; quicker method / less labour intensive; prevents decrease in crop yield; reduces chance of food insecurity; do not need to reintroduce a predator; biological control can become invasive; max [3] disadvantages: affects non-target species / soil organisms; affects pollinators; can become resistant to insecticide; can enter water bodies / can enter food chain / bioaccumulation described / biomagnification described; 3(b)(vi) N = 541; 4 grasshopper = 0.095 AND earwig = 0.182 AND aphid = 0.0079 AND thrip = 0.031;  n  2 = 0.316 / 0.32;     N  D = 0.684 / 0.68;

This question in 8291/22 Oct/Nov 2023

3 (a) Fig. 3.1 shows incoming and outgoing solar radiation. Key incoming solar radiation outgoing solar radiation Sun space reflector stratospheric aerosols high altitude stratospherestratosphere clouds tropospheretroposphere low altitude clouds land land snow and ice ocean Fig. 3.1 (i) Name the layer of the atmosphere directly above the stratosphere. … [1] (ii) Suggest why snow and ice increase surface albedo. … … [1] (iii) Some of the Sun’s energy is re-emitted back into the atmosphere as infrared radiation. Explain how some of this infrared radiation is prevented from leaving the Earth’s atmosphere. … … … … [2] (iv) Suggest how a space reflector could counteract climate change. … … … … [2] (b) Explain why eating a plant-based diet can reduce the impact of climate change. … … … … [2] (c) State the three major gases in Earth’s unpolluted atmosphere. 1 … 2 … 3 … [3] (d) Explain why international agreements are needed to control air pollution. … … … … [2] [Total: 13]

13 marks

Mark scheme: 3(a)(i) mesosphere; 1 3(a)(ii) white surfaces / snow and ice reflect (incoming) solar radiation / sunlight; 1 3(a)(iii) any two from: 2 (IR radiation) absorbed / trapped; by greenhouse gases / named gas e.g. carbon dioxide / methane / water; reflected by clouds / reflected back to surface; 3(a)(iv) any two from: 2 incoming solar radiation rays; reflect / bounce back; before it reaches Earth’s surface / before it gets trapped in atmosphere /; reduce temperature (of Earth’s surface); 3(b) any two from: 2 cattle/livestock produce methane; (produce methane which is a) greenhouse gas; livestock rearing requires more energy than growing crops; 3(c) nitrogen; 3 oxygen; carbon dioxide; 3(d) any two from: 2 air pollution knows no boundaries; carried by wind/air currents; pollution in one country effects pollution in others; reference to global issues e.g. ozone ‘hole’/climate change /acid deposition; needs co-operation between countries / countries need to work together;

This question in 8291/23 Oct/Nov 2023

2 (a) In 2022, 80% of the timber used in the UK was imported. (i) Suggest one negative impact for the UK of importing timber. … [1] (ii) Financial incentives were offered to UK farmers to grow trees on agricultural land. Suggest two negative impacts of growing trees on agricultural land. 1 … … 2 … … [2] (b) Explain how growing more trees reduces the impact of carbon dioxide in the atmosphere. … … … … [2] (c) The photograph in Fig. 2.1 shows a forest, a road and a lake. Fig. 2.1 Describe how the photograph in Fig. 2.1 shows evidence of fragmentation. … … … … … … [3] (d) Pollinating insects enable trees to reproduce. Fig. 2.2 shows the broken-belted bumblebee, which is a pollinating insect. Fig. 2.2 The map in Fig. 2.3 shows the distribution of broken-belted bumblebees in part of the UK. Key N population of broken-belted bumblebee Scotland England Wales (i) Describe the distribution of broken-belted bumblebees shown in Fig. 2.3. … … … … [2] (ii) The data for the distribution map in Fig. 2.3 was collected using a survey. People completed an online survey for any species of bumblebee they observed. Fig. 2.4 shows the form used to collect the data. species: when you saw it: where you saw it: map grid reference: contact information: Fig. 2.4 Suggest the limitations of this type of bee population distribution survey. … … … … … … [3] (e) A scientist investigates the population of broken-belted bumblebees using a transect method. The transect is a measured straight line where the population of broken-belted bumblebees are located. The length of this transect line is 10 m. Describe how the scientist can use this transect line to estimate the population of broken- belted bumblebees. … … … … … … … … [4] (f) The diagram in Fig. 2.5 shows a natural bee nest in a tree. Fig. 2.5 Fig. 2.6 shows two types of artificial bee nest: a sun hive and a wooden hive. sun hive wooden hive Fig. 2.6 Suggest the benefits and limitations of the two artificial bee nests. … … … … … … … … … … [5] (g) The Asian hornet is an invasive species to the UK. Explain how the Asian hornet can endanger bumblebee populations in the UK. … … … … … … [3] [Total: 25]

25 marks

Mark scheme: 2(a)(i) any one from: prices can be increased (by other country); lack of self-reliance / reliance on other countries / idea of imbalance of supply and demand; not sustainable; stated economic impact (e.g. cost of transport / cost of importing / impact on UK timber industry; energy use of transport or using vehicles / transport has carbon footprint / atmospheric impact of use of transport / named air pollution linked to transport; may introduce, invasive species / disease; 1 2(a)(ii) any two or one developed from: livestock cannot graze on land / less space for livestock; food or crops, not grown or less grown / less yield or less space for food or crops; leads to food insecurity; long lead time / timber harvest will not be available for many years / trees take a long time to grow; 2 2(b) reference to (trees) photosynthesise; trees remove or store, carbon dioxide / carbon dioxide reactant (in photosynthesis) / carbon dioxide  water (→ glucose  oxygen); 2 Question Answer Marks 2(c) any three from: road separates or fragments the forest or habitat / one side of the forest is cut off by a road / road separates animals or organisms; power lines / pylons, separate or fragment forest / pylons separate animals or organisms; no access to the lake / animals have to cross the road to reach the lake; loss of trees at edges or barren land around edges of forest or edges road; 3 2(d)(i) idea of most in, (north) Scotland / north / few in England AND Wales; any one from population: dispersed / scattered / spread out; more along coast / more west (Wales) / few in east / few in central England or in centre / cluster south (England); 2 2(d)(ii) any three from: public are not experts / misidentification / wrong species counted; bees, may be missed / counted more than once / move around / difficult to see / difficult to get close to / miscounting / inputted incorrectly / counting errors / error in remembering number counted; no details on how the sightings were made e.g. random / systematic / stated conditions e.g. weather, temperature; some areas give more or less returns / no information on number of people reporting / no information on number of bees; difficulty in finding map grid reference / location may not be correct / wrong grid; need access to, smartphone / computer / internet; 3 Question Answer Marks 2(e) for max [4] at least one from each section (method, repeat, estimation) plus any other marking point: method: count the bees observed / count bees (along transect or line); within stated distance either side or along transect or line; e.g. 2 m repeat: repeat at different times (of day / year); repeat complete investigation AND average; estimation: idea of scaling up e.g. determine number of bees in 1 m or 1 m2 and multiply by total area; 4 Question Answer Marks 2(f) any five from: artificial hives / ORA natural nests: bees may not adapt to artificial hives / hives might not be suitable to bees’ needs; quality or quantity of honey may be different / different productivity in artificial hives; idea of cost of artificial hives; conditions controlled; bees can be, fed / given water; hives can be cleaned; disease can be treated; easier to collect honey / hive in convenient location / ease of maintenance or monitoring (for beekeeper); can hold larger population / hives are larger than nests / fixed size; last longer / more durable; protects from predators; sun hive: tree or location same as nest / location is in natural habitat; similar shape to natural nest; can get blown away / damaged by wind or weather / at risk due to deforestation; wooden hive: easier to monitor at ground level; wood destroyed by termites / wood rots; AVP; 5 2(g) any three from: (out)compete for, habitat / nesting sites / shelter / territory; (out)compete for stated resources e.g. food / disrupt food chain; carry disease; breed quicker (than bees); predators of bees / prey on bees; no known predators (for hornets); 3

This question in 8291/21 May/June 2024

3 Methane is an atmospheric pollutant. (a) Fig. 3.1 shows the concentration of methane gas in the atmosphere from 1983 to 2022. 1950 1900 1850 1800 methane concentration 1750 / parts per billion 1700 1650 1600 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 year Fig. 3.1 (i) Describe the atmospheric impacts of the trend shown in Fig. 3.1. … … … … [2] (ii) State two sources of methane. 1 … 2 … [2] (b) Sulfur dioxide is an atmospheric pollutant. In 1990, the USA introduced strategies for managing sulfur dioxide emissions. Fig. 3.2 and Fig. 3.3 show data for annual sulfur dioxide emissions for 1990 and 2020 in the USA. Key sulfur dioxide emissions N 270000 tonnes 90000 tonnes <18000 tonnes 1990 Fig. 3.2 2020 Fig. 3.3 (i) Evaluate the success of the strategies introduced to manage sulfur dioxide emissions. … … … … … … [3] (ii) Explain how sulfur dioxide forms acid deposition. … … … … [2] (iii) State one type of wet acid deposition and one type of dry acid deposition. wet acid deposition … dry acid deposition … [2] (iv) Combustion of fossil fuels contributes to acid deposition. Describe strategies to reduce the impact of acid deposition from the combustion of fossil fuels. … … … … … … [3] (c) Fig. 3.4 shows mustard greens, which are a food crop. 15–20cm Fig. 3.4 A scientist uses four different pH values of water to investigate the effect of acid deposition on the yield of mustard greens. The pH values are pH 6.0, 4.0, 3.5 and 3.0. The scientist uses this method. • Thoroughly mix 15 kg of soil. • Fill 10 pots, each with 1.5 kg of soil. • Put 1 mustard green plant in each pot. • Spray each of the 10 plants with pH 6.0 water continuously for 1.5 hours a day. • After 3 months, harvest and dry all the leaves. • Measure the mass of the leaves. • Repeat the method for each pH value. (i) Suggest why the 15 kg of soil must be thoroughly mixed. … … [1] (ii) Suggest why a pH value of 6.0 is used. … … [1] (iii) Identify the independent variable in this investigation. … [1] (iv) Suggest why 10 plants are used for each pH value. … … [1] (v) Suggest why the leaves are dried before their mass is measured. … … [1] (vi) Table 3.1 shows the mean dry mass of the leaves from the 10 plants at each pH value. Table 3.1 pH 6.0 4.0 3.5 3.0 mean dry mass 59.28 58.05 58.00 48.36 / g Write a suitable conclusion for the results. … … [1] (vii) Calculate the range for the mean dry mass of the leaves. Give your answer to two decimal places. range = … g [1] (viii) The scientist investigates the impact of acid deposition on leaf damage. Table 3.2 shows the results. Table 3.2 pH 6.0 4.0 3.5 3.0 percentage of leaf 0.0 0.0 4.3 10.4 damage Write a suitable conclusion for the results. … … [1] [Total: 22]

22 marks

Mark scheme: 3(a)(i) any two from: methane is a greenhouse gas / increase in greenhouse gases; (increase in enhanced) greenhouse effect; increase (global) temperature / climate change; 2 3(a)(ii) any two from: rice fields or paddies; livestock or named livestock (digestion); landfill; decomposition of vegetation / rotting of vegetation; released from melting permafrost; peat (bogs) / wetlands; mining / rock extraction / fracking; 2 3(b)(i) successful because: emissions decreased; no areas greater than 18 000 tonnes (in 2020) / idea of reduction in emissions in east / no 270 000 tonne emissions in 2020 less successful because: increase in emissions on west (coast); 3 3(b)(ii) (in the atmosphere SO2) reacts with (rain)water (and oxygen); forms sulfuric acid; 2 3(b)(iii) wet acid deposition: snow / rain / hail / fog; dry acid deposition: dust / gas(es); 2 Question Answer Marks 3(b)(iv) any three from or developed responses: use of renewable resources / stated example e.g. solar; fuel desulfurisation; flue gas desulfurisation; description gases dissolved in water; neutralised/reacted/removed with limestone or calcium carbonate or CaCO3; electrostatic removal (from emissions); catalytic convertors; restricting vehicle use / electric cars or EVs / use public transport / car pooling / idea of encouraging walking or cycling; international agreements / legislation / clean air zones / limits on emissions from factories; polluter pays principle / fines; idea of education or raising awareness; 3 3(c)(i) keep soil the same / same consistency / same composition / even distribution (of nutrients or particles or minerals); 1 3(c)(ii) any one from: pH of non-acid deposition; compare results with non-acid rain; control; 1 3(c)(iii) pH (of water); 1 3(c)(iv) identify anomalous result or outlier / trend can be identified / reduce impact of anomalous results / determine a mean; 1 3(c)(v) fair test / results are comparable / amount of water in each leaf is variable (in different plants or leaves); 1 Question Answer Marks 3(c)(vi) any one from: acid precipitation reduces crop yield; the lower the pH the lower the yield; the more acidic the pH the lower the yield / ORA; the greatest reduction in yield was for pH 3.0; highest yield at pH 6.0 / higher pH gives higher yield; 1 3(c)(vii) 10.92; 1 3(c)(viii) any one from: pH 3.5 and lower damages leaves; pH 4.0 and higher does not damage leaves; the more acidic / the lower the pH, the more damage / ORA; pH 3.0 / lowest pH, causes most damage; damage increases as pH decreases; 1

This question in 8291/21 May/June 2024

2 (a) Scientists use tree ring data to investigate tree growth in a local area. Each year a tree grows, a new tree ring forms. Wider tree rings form when trees grow more rapidly. The scientists make this hypothesis: ‘Emissions from a factory have a negative impact on tree growth in the local area.’ Fig. 2.1 shows tree ring data for one species of tree over an 80‑year period in the local area. The factory was opened at the start of the 80‑year period. tree ring width average tree ring width 0 20 40 60 80 year Fig. 2.1 The horizontal line represents the average tree ring width for this species of tree. Values above the horizontal line indicate higher than average tree ring width. (i) Discuss whether the data in Fig. 2.1 supports the scientists’ hypothesis. … … … … … … [3] (ii) Tree ring data is also used to reconstruct past climate conditions. State two other methods for reconstructing past climate conditions. 1 … 2 … [2] (b) A scientist uses a computer model to predict the effect of ground level ozone on plant growth over a 3‑year period. The model: • uses two concentrations of ozone, 20 and 120 parts per million (ppm) • predicts the mass of the plant stem every month for 3 years. Fig. 2.2 shows the results of the model. Key ozone concentration 20 ppm 120 ppm 280 270 260 250mass of plant stem / g 240 230 220 210 0 0.5 1.0 1.5 2.0 2.5 3.0 year Fig. 2.2 (i) Describe the results of the model shown in Fig. 2.2. … … … … [2] (ii) Another scientist wants to repeat the computer model. Suggest three pieces of additional information needed for the model to be repeated. 1 … 2 … 3 … [3] (c) Ground level ozone can form photochemical smog. (i) State the layer of the atmosphere which contains ground level ozone. … [1] (ii) Describe the formation of photochemical smog. … … … … … … [3] (iii) State two impacts of photochemical smog on human health. 1 … 2 … [2] (d) Table 2.1 shows the concentration of ground level ozone in ppm for a 24‑hour period in a USA city. Table 2.1 time ozone concentration / hour / ppm 0 0.10 3 0.10 6 0.30 9 0.34 12 0.62 15 0.92 18 0.84 21 0.18 24 0.10 (i) Plot the data as a line graph on the grid. Join each point with a straight line. [5] (ii) Calculate the range for ground level ozone concentration in the 24‑hour period. range = … ppm [1] (iii) A student concludes that the maximum ozone concentration in the 24‑hour period is 0.92 ppm. State whether the student’s conclusion is sensible. Justify your answer. … … [1] [Total: 23]

23 marks

Mark scheme: 2(a)(i) max two justifications: year 0 to 20: higher than average tree ring width; year 50 to 80: higher than average tree ring width; idea of significant fluctuations; max two conclusion: (no impact from factory because) more years with higher than average tree ring width / more years with above average growth; other factors impact tree growth / factor named e.g. drought / fire / temperature / disease; 2(a)(ii) ice cores; historical accounts; 2 2(b)(i) any two from: for both concentrations mass increases with time; increased ozone concentration decreases plant mass / the longer the plants are exposed to ozone the greater the difference in mass between 20 and 120 ppm; little effect in first year; relevant quoted comparative data e.g. after 3 years 25 g different; 2 2(b)(ii) any three from: total number of plants; species of plant; stated growing conditions ;;; e.g. soil pH, amount of light, volume of water, spacing, temperature, organic content of soil AVP; 3 2(c)(i) troposphere; 1 2(c)(ii) in the presence of sunlight; any two from reaction of ozone with: oxides of nitrogen ; particulates; volatile organic compounds / VOCs; 3 Question Answer Marks 2(c)(iii) any two from: eye irritation; respiratory irritation; 2 2(d)(i) axes labelled with units; time / hour AND concentration / ppm sensible linear scale with plotted points that cover at least half of grid; plotting 78 correct; plotting all 9 correct; straight line drawn with ruler between each point connecting AND not extrapolated beyond 24 hours; 5 2(d)(ii) 0.82; 1 2(d)(iii) no AND any one from: do not know concentration between hours 1518; data is not repeated; concentration at 15 could be anomalous; 1

This question in 8291/22 May/June 2024

2 (a) Scientists use tree ring data to investigate tree growth in a local area. Each year a tree grows, a new tree ring forms. Wider tree rings form when trees grow more rapidly. The scientists make this hypothesis: ‘Emissions from a factory have a negative impact on tree growth in the local area.’ Fig. 2.1 shows tree ring data for one species of tree over an 80‑year period in the local area. The factory was opened at the start of the 80‑year period. tree ring width average tree ring width 0 20 40 60 80 year Fig. 2.1 The horizontal line represents the average tree ring width for this species of tree. Values above the horizontal line indicate higher than average tree ring width. (i) Discuss whether the data in Fig. 2.1 supports the scientists’ hypothesis. … … … … … … [3] (ii) Tree ring data is also used to reconstruct past climate conditions. State two other methods for reconstructing past climate conditions. 1 … 2 … [2] (b) A scientist uses a computer model to predict the effect of ground level ozone on plant growth over a 3‑year period. The model: • uses two concentrations of ozone, 20 and 120 parts per million (ppm) • predicts the mass of the plant stem every month for 3 years. Fig. 2.2 shows the results of the model. Key ozone concentration 20 ppm 120 ppm 280 270 260 250mass of plant stem / g 240 230 220 210 0 0.5 1.0 1.5 2.0 2.5 3.0 year Fig. 2.2 (i) Describe the results of the model shown in Fig. 2.2. … … … … [2] (ii) Another scientist wants to repeat the computer model. Suggest three pieces of additional information needed for the model to be repeated. 1 … 2 … 3 … [3] (c) Ground level ozone can form photochemical smog. (i) State the layer of the atmosphere which contains ground level ozone. … [1] (ii) Describe the formation of photochemical smog. … … … … … … [3] (iii) State two impacts of photochemical smog on human health. 1 … 2 … [2] (d) Table 2.1 shows the concentration of ground level ozone in ppm for a 24‑hour period in a USA city. Table 2.1 time ozone concentration / hour / ppm 0 0.10 3 0.10 6 0.30 9 0.34 12 0.62 15 0.92 18 0.84 21 0.18 24 0.10 (i) Plot the data as a line graph on the grid. Join each point with a straight line. [5] (ii) Calculate the range for ground level ozone concentration in the 24‑hour period. range = … ppm [1] (iii) A student concludes that the maximum ozone concentration in the 24‑hour period is 0.92 ppm. State whether the student’s conclusion is sensible. Justify your answer. … … [1] [Total: 23]

23 marks

Mark scheme: 2(a)(i) max two justifications: year 0 to 20: higher than average tree ring width; year 50 to 80: higher than average tree ring width; idea of significant fluctuations; max two conclusion: (no impact from factory because) more years with higher than average tree ring width / more years with above average growth; other factors impact tree growth / factor named e.g. drought / fire / temperature / disease; 2(a)(ii) ice cores; historical accounts; 2 2(b)(i) any two from: for both concentrations mass increases with time; increased ozone concentration decreases plant mass / the longer the plants are exposed to ozone the greater the difference in mass between 20 and 120 ppm; little effect in first year; relevant quoted comparative data e.g. after 3 years 25 g different; 2 2(b)(ii) any three from: total number of plants; species of plant; stated growing conditions ;;; e.g. soil pH, amount of light, volume of water, spacing, temperature, organic content of soil AVP; 3 2(c)(i) troposphere; 1 2(c)(ii) in the presence of sunlight; any two from reaction of ozone with: oxides of nitrogen ; particulates; volatile organic compounds / VOCs; 3 Question Answer Marks 2(c)(iii) any two from: eye irritation; respiratory irritation; 2 2(d)(i) axes labelled with units; time / hour AND concentration / ppm sensible linear scale with plotted points that cover at least half of grid; plotting 78 correct; plotting all 9 correct; straight line drawn with ruler between each point connecting AND not extrapolated beyond 24 hours; 5 2(d)(ii) 0.82; 1 2(d)(iii) no AND any one from: do not know concentration between hours 1518; data is not repeated; concentration at 15 could be anomalous; 1

This question in 8291/23 May/June 2024

3 (a) A farmer investigates insect pests on soybean plants. Fig. 3.1 shows soybean plants. Fig. 3.1 The farmer investigates an area of soybean plants that is 7 rows by 7 columns. There is a total of 49 soybean plants. Fig. 3.2 shows the results from a random number generator. The farmer uses these results to select a sample of 6 soybean plants. Each number represents a row number and a column number. 56 71 29 56 33 22 32 60 53 28 23 72 13 Fig. 3.2 The farmer starts at number ‘56’. ‘56’ represents row 5 and column 6. The farmer circles this plant on Fig. 3.3. The farmer ignores a number in Fig. 3.2 if: • any part of the number is greater than 6 • a number is repeated. Fig. 3.3 shows the area of soybean plants the farmer investigates. column number 0 1 2 3 4 5 6 0 1 2 row 3 number 4 5 6 Fig. 3.3 (i) The farmer samples a total of 6 plants. The first 3 soybean plants selected from the random number generator are circled. Complete Fig. 3.3 by circling the 3 other soybean plants the farmer samples. [1] (ii) State one benefit of using a random number generator to select the soybean plants. … … [1] (b) The farmer uses a beating tray to investigate insect population. (i) Describe a beating tray method the student can use to estimate the total number of insects on the 49 soybean plants. … … … … … … … … … … [5] (ii) Describe two limitations of using a beating tray for investigating the insect population on soybean plants. 1 … … 2 … … [2] (c) The farmer concludes that the soybean plants are infested with aphids. Aphids are insects that eat soybean plants and reduce crop yield. The farmer introduces the harlequin beetle to the soybean plants. The harlequin beetle is a flying insect and is a predator of the aphids. Fig. 3.4 shows a harlequin beetle. 7 mm Fig. 3.4 The farmer records the population of aphids in 2 different fields. Fig. 3.5 shows the results. Key field 1: no predator field 2: predator added 300 250 200 mean number of aphids 150per leaf predator added to field 2 100 50 00 5 10 15 20 25 30 35 40 45 50 55 60 65 day Fig. 3.5 (i) Name the type of method for controlling the aphid population using a predator. … [1] (ii) Suggest why the predator was not added to field 1. … [1] (iii) Suggest why the aphid population was measured before the predator was added to field 2. … … [1] (iv) Write a conclusion using the data in Fig. 3.5. … … … … … … [3] (v) Suggest why the farmer covers the soybean plants with nets after the predator is added. … … … … [2] (d) The harlequin beetle was introduced to North America and Europe to control aphid populations. The harlequin beetle is now considered to be one of the world’s most invasive species. The harlequin beetle becomes inactive when temperatures are lower than 10 °C. Suggest why climate change could benefit the harlequin beetle. … … [1] (e) Increasing crop productivity by reducing pests is a strategy for managing food security. Hydroponics can also improve food security. (i) Explain how hydroponics improves food security. … … … … … … … … [4] (ii) Describe the limitations of large-scale food stockpiling as a method of reducing food insecurity. … … … … … … [3] (iii) Outline the impacts of food insecurity. … … … … … … … … [4] [Total: 29]

29 marks

Mark scheme: 3(a)(i) 3 plants circled correctly at 32, 60, 53; 1 3(a)(ii) avoids bias / equal chance of selection; 1 3(b)(i) method: 5 (on one plant) tap / hit / shake the plant (gently with a stick); collect falling insects on the beating tray; count (only) the insects; processing: repeat (the beating tray) method and take a mean; idea of scaling up; e.g. multiply the mean number of insects in the sampled area / plants sampled by the total number of plants 3(b)(ii) any two from: 2 soybean plants are close to ground so difficult to get lower insects in tray; beating can damage the plant; beating cannot be used on wet plants; flying insects fly away / some insects might escape; some insects left on plant / not all insects will fall on the tray; 3(c)(i) biological; 1 3(c)(ii) control / to compare the result; 1 3(c)(iii) any one from: 1 to ensure that field 1 and field 2 had a comparable number of aphids (at the start); to see if the predator has an effect; 3(c)(iv) predator reduces the aphid population; 3 predator takes 8–12 days to make an impact / it took 10 days for the introduced predator to work; relevant comparable quoted data e.g. difference in aphid population with no predator is 215 (255-40) by day 65; 3(c)(v) any two from: 2 prevents predator flying away; prevents new pests / insects landing on the plants; prevents new predators landing on the plants; (so that the farmer knows) it is the harlequin beetle predator that has reduced the aphid population; 3(d) any one from: 1 increased temperatures mean it will not become inactive; native species may die at hotter temperatures / in changed conditions; beetle competitors / predators might die; expand range of beetle; 3(e)(i) plants grown at high density / high crop yield (per unit area); 4 any three from: plants grown without soil / roots are in water that contains nutrients; plants less prone to soil pests; plants can be grown in areas with soil erosion / poor quality soil; plants can be grown inside; plants can be grown in controlled conditions; e.g. controlled lighting yields not dependent on weather conditions / rainfall; crops are not seasonal / can be grown all year; 3(e)(ii) any three from: 3 leads to food shortages; more likely to benefit rich; food could rot if not stored properly; danger of losing (large) quantity of food at one time; fresh food loses nutritional value if stored for long period; idea that food should be distributed to people who are hungry now; 3(e)(iii) any four from: 4 food scarcity; nutritional deficiency / malnutrition; famine / starvation; poverty; forces migration; conflict;

This question in 8291/21 Oct/Nov 2024

1 Fig. 1.1 shows a vertical aquaculture farm. Content removed due to copyright restrictions. Fig. 1.1 In Fig. 1.1, seaweed grows from ropes under the water. Shellfish such as mussels grow on chains. Scallops and oysters are farmed in nets and cages. Seaweed photosynthesises. Some species of seaweed grow up to 0.5 m in one day. The seaweed is harvested for use as human and animal food, organic fertiliser and biofuel; it is also used as an ingredient in natural medicines, cosmetics and bioplastics. Any seaweed that is not harvested falls to the sea floor and is covered by layers of sediment. (a) Vertical aquaculture farming is an example of adaptation to climate change. (i) Suggest why some crop farmers need to adapt to climate change by investing in aquaculture. … … … … … … [3] (ii) Suggest how vertical aquaculture can reduce the concentration of carbon dioxide in the atmosphere. … … … … … … [3] (iii) Suggest one benefit of vertical aquaculture farming other than reducing the impacts of climate change. … [1] (b) Fig. 1.2 shows the annual yield of seaweed from aquaculture farms in China from 1978 to 2014. 2.0 1.5 annual yield of 1.0 seaweed / million tonnes 0.5 0 1975 1985 1995 2005 2015 year Fig. 1.2 (i) Describe the trend in the annual yield of seaweed from aquaculture farms in China from 1978 to 2014. … … … … … … [3] (ii) Suggest one reason for a decrease in annual yield of seaweed from aquaculture farms. … … [1] (c) The seaweed aquaculture farming sector is predicted to grow. Fig. 1.3 shows three predictions for global yield of seaweed from aquaculture farms based on three different percentage growth rates. Key percentage growth rate per year 6% 12% 20% 12 000 10 000 annual 8000 yield of seaweed 6000 / million tonnes 4000 2000 0 2020 2025 2030 2035 2040 2045 2050 year Fig. 1.3 Table 1.1 shows the area of ocean required by 2050 for each percentage growth rate. Table 1.1 percentage growth rate area of ocean required by 2050 per year / km2 6 12 797 12 74 524 20 677 832 Suggest why there is concern about the impact of a 20% growth rate in global aquaculture. … … … … [2] (d) Overfishing impacts ecosystems. Describe strategies for reducing the impact of overfishing. … … … … … … [3] (e) The ocean is a source of salt water. (i) State three sources of surface fresh water. 1 … 2 … 3 … [3] (ii) The atmosphere contains water vapour. State three other gases in unpolluted air. 1 … 2 … 3 … [3] (f) Water is an abiotic component of an ecosystem. State three other abiotic components of an ecosystem. 1 … 2 … 3 … [3] [Total: 25]

25 marks

Mark scheme: Question Answer Marks 1(a)(i) any three from: 3 increasing global temperatures / global warming; extreme or severe weather; examples of extreme weather, e.g. drought / flooding / hurricanes; rising sea levels; (leading to) loss of land (for crops or agriculture); non-optimum conditions for crop growth (due to climate change); crop failure / reduced crop yield / less food; 1(a)(ii) any three from: 3 seaweed act as carbon sinks / stores / shellfish act as carbon sinks / stores; seaweed absorbs or uses carbon dioxide during photosynthesis; seaweed is fast growing so large volumes of carbon dioxide removed; provide an alternate food source other than meat based diet; (acts as raw ingredient in many products so) reduces need to extract other raw ingredients; (biofuels) reduce need for fossil fuels; 1(a)(iii) any one from: 1 habitat for marine wildlife; storm-surge protection; improved food security; high (aquatic) crop density or yield; 1(b)(i) any three from: 3 overall increase; 1978 to (1987–)1990 no change or little change / stable; decrease (2005–)2006 to 2007; relevant quoted data trend; 1(b)(ii) any one from: 1 extreme weather or description, e.g. storms / hurricanes; disease; unfavourable growing conditions or description; outcompeted by other species; competition from other ocean activities / industries; 1(c) any two from: 2 large area of ocean needed; limits (other) activities that can take place in ocean; competition with fishing / traditional marine harvesting; concern over impact on native species; increase in pollution (from boats); 1(d) any three from or developed: 3 legislation / international agreement; sustainable harvesting; protected areas; stated fisheries regulation: quotas / catch limits / closed seasons; changes to net size (protects juveniles) / changes to fishing method such as pole and line (reduces bycatch); 1(e)(i) any three from: 3 ice sheets; glaciers; lakes; rivers / streams; swamps; marshes; permafrost; 1(e)(ii) any three from: 3 nitrogen; oxygen; carbon dioxide; argon / noble gases; 1(f) any three from: 3 temperature; humidity; oxygen; carbon dioxide; salinity; (sun)light; pH;

This question in 8291/22 Oct/Nov 2024

3 (a) A farmer investigates insect pests on soybean plants. Fig. 3.1 shows soybean plants. Fig. 3.1 The farmer investigates an area of soybean plants that is 7 rows by 7 columns. There is a total of 49 soybean plants. Fig. 3.2 shows the results from a random number generator. The farmer uses these results to select a sample of 6 soybean plants. Each number represents a row number and a column number. 56 71 29 56 33 22 32 60 53 28 23 72 13 Fig. 3.2 The farmer starts at number ‘56’. ‘56’ represents row 5 and column 6. The farmer circles this plant on Fig. 3.3. The farmer ignores a number in Fig. 3.2 if: • any part of the number is greater than 6 • a number is repeated. Fig. 3.3 shows the area of soybean plants the farmer investigates. column number 0 1 2 3 4 5 6 0 1 2 row 3 number 4 5 6 Fig. 3.3 (i) The farmer samples a total of 6 plants. The first 3 soybean plants selected from the random number generator are circled. Complete Fig. 3.3 by circling the 3 other soybean plants the farmer samples. [1] (ii) State one benefit of using a random number generator to select the soybean plants. … … [1] (b) The farmer uses a beating tray to investigate insect population. (i) Describe a beating tray method the student can use to estimate the total number of insects on the 49 soybean plants. … … … … … … … … … … [5] (ii) Describe two limitations of using a beating tray for investigating the insect population on soybean plants. 1 … … 2 … … [2] (c) The farmer concludes that the soybean plants are infested with aphids. Aphids are insects that eat soybean plants and reduce crop yield. The farmer introduces the harlequin beetle to the soybean plants. The harlequin beetle is a flying insect and is a predator of the aphids. Fig. 3.4 shows a harlequin beetle. 7 mm Fig. 3.4 The farmer records the population of aphids in 2 different fields. Fig. 3.5 shows the results. Key field 1: no predator field 2: predator added 300 250 200 mean number of aphids 150per leaf predator added to field 2 100 50 00 5 10 15 20 25 30 35 40 45 50 55 60 65 day Fig. 3.5 (i) Name the type of method for controlling the aphid population using a predator. … [1] (ii) Suggest why the predator was not added to field 1. … [1] (iii) Suggest why the aphid population was measured before the predator was added to field 2. … … [1] (iv) Write a conclusion using the data in Fig. 3.5. … … … … … … [3] (v) Suggest why the farmer covers the soybean plants with nets after the predator is added. … … … … [2] (d) The harlequin beetle was introduced to North America and Europe to control aphid populations. The harlequin beetle is now considered to be one of the world’s most invasive species. The harlequin beetle becomes inactive when temperatures are lower than 10 °C. Suggest why climate change could benefit the harlequin beetle. … … [1] (e) Increasing crop productivity by reducing pests is a strategy for managing food security. Hydroponics can also improve food security. (i) Explain how hydroponics improves food security. … … … … … … … … [4] (ii) Describe the limitations of large-scale food stockpiling as a method of reducing food insecurity. … … … … … … [3] (iii) Outline the impacts of food insecurity. … … … … … … … … [4] [Total: 29]

29 marks

Mark scheme: 3(a)(i) 3 plants circled correctly at 32, 60, 53; 1 3(a)(ii) avoids bias / equal chance of selection; 1 3(b)(i) method: 5 (on one plant) tap / hit / shake the plant (gently with a stick); collect falling insects on the beating tray; count (only) the insects; processing: repeat (the beating tray) method and take a mean; idea of scaling up; e.g. multiply the mean number of insects in the sampled area / plants sampled by the total number of plants 3(b)(ii) any two from: 2 soybean plants are close to ground so difficult to get lower insects in tray; beating can damage the plant; beating cannot be used on wet plants; flying insects fly away / some insects might escape; some insects left on plant / not all insects will fall on the tray; 3(c)(i) biological; 1 3(c)(ii) control / to compare the result; 1 3(c)(iii) any one from: 1 to ensure that field 1 and field 2 had a comparable number of aphids (at the start); to see if the predator has an effect; 3(c)(iv) predator reduces the aphid population; 3 predator takes 8–12 days to make an impact / it took 10 days for the introduced predator to work; relevant comparable quoted data e.g. difference in aphid population with no predator is 215 (255-40) by day 65; 3(c)(v) any two from: 2 prevents predator flying away; prevents new pests / insects landing on the plants; prevents new predators landing on the plants; (so that the farmer knows) it is the harlequin beetle predator that has reduced the aphid population; 3(d) any one from: 1 increased temperatures mean it will not become inactive; native species may die at hotter temperatures / in changed conditions; beetle competitors / predators might die; expand range of beetle; 3(e)(i) plants grown at high density / high crop yield (per unit area); 4 any three from: plants grown without soil / roots are in water that contains nutrients; plants less prone to soil pests; plants can be grown in areas with soil erosion / poor quality soil; plants can be grown inside; plants can be grown in controlled conditions; e.g. controlled lighting yields not dependent on weather conditions / rainfall; crops are not seasonal / can be grown all year; 3(e)(ii) any three from: 3 leads to food shortages; more likely to benefit rich; food could rot if not stored properly; danger of losing (large) quantity of food at one time; fresh food loses nutritional value if stored for long period; idea that food should be distributed to people who are hungry now; 3(e)(iii) any four from: 4 food scarcity; nutritional deficiency / malnutrition; famine / starvation; poverty; forces migration; conflict;

This question in 8291/23 Oct/Nov 2024

3 An increase in wild fires is an impact of climate change. (a) Explain how climate change leads to wild fires. … … … … … … [3] (b) Table 3.1 shows the number of wild fires recorded in Brazil from 2013 to 2019. Table 3.1 Content removed due to copyright restrictions. (i) Plot the data in Table 3.1 as a bar chart. [4] (ii) Suggest why the actual number of wild fires in 2019 was greater than 80 500. … … [1] (c) Explain how climate change can cause extreme rainfall. … … … … … … [3] (d) In the year 2000, four different computer models were used to predict future changes to the mean global surface temperature. Fig. 3.1 shows these four predictions for global surface temperature compared to measured data from the year 2000. Key measured data model A model B model C model D 6 5 4 3 global surface temperature 2 change / °C 1 0 –1 –2 1900 1950 2000 2050 2100 year Fig. 3.1 (i) State what Fig. 3.1 shows about the global surface temperature before the year 2000. … [1] (ii) Suggest two reasons for the differences in the four predictions. 1 … … 2 … … [2] (e) Fig. 3.2 shows the locations of some research bases in Antarctica. Key research base Antarctic continent ice shelf Haakon VII Sea Weddell Sea Davis Sea Bellinghausen Sea South Pole Amundsen Mawson Sea Sea Ross Sea 0 1000 Dumont km D’urville Sea Fig. 3.2 (i) Suggest why climate change is a concern for Antarctica. … … [1] (ii) Describe how the impacts of tourism are controlled in Antarctica. … … … … … … [3] [Total: 18]

18 marks

Mark scheme: 3(a) any three from: 3 MP1 higher temperatures; MP2 drought; MP3 less rainfall; MP4 vegetation drier; 3(b)(i) MP1 axes labels e.g. y-axis label: number of (recorded) wild fires AND x-axis: year; 4 MP2 sensible linear scale, plotted points occupy half the grid; MP3 6–7 bars of correct height; MP4 bars drawn with a ruler and equal width and not touching; 3(b)(ii) any one from: 1 not all fires reported; AVP; 3(c) any three from: 3 MP1 global warming / increased temperatures; MP2 more evaporation; MP3 more convection; MP4 more moisture to form clouds; 3(d)(i) any one from: 1 MP1 lower value (than 2000 value); MP2 (from 1900 to 2000) gradually increasing; 3(d)(ii) any two from: 2 MP1 based on different theories / policies; MP2 different data used / stated example e.g. temperature; MP3 biased data; MP4 improved or different technology / knowledge; 3(e)(i) any one from: 1 MP1 increased temperatures can melt ice; MP2 many research bases on ice shelfs; MP3 loss of habitat / loss of biodiversity; 3(e)(ii) any three from: 3 MP1 Antarctic Treaty / legislation / international agreement; MP2 people not allowed to enter protected areas / restricted activities; MP3 waste management / waste taken away from Antarctica; MP4 permits for travel; MP5 guides required; MP6 restriction of tourist / ship numbers;

This question in 8291/23 May/June 2025

1 (a) Methane is a greenhouse gas. Greenhouse gases contribute to climate change. (i) Define the term greenhouse gas. … … [1] (ii) State one danger of a build-up of methane in the atmosphere other than climate change. … [1] (b) Computer models are used to estimate the global atmospheric methane budget measured in teragrams, Tg. 1 Tg = 1 × 109 kg. Sources add methane into the atmosphere and sinks remove methane from the atmosphere. Fig. 1.1 shows data for the global atmospheric methane budget. 600 250 500 200 400 mean global mean methane 150 300 global removal methane / Tg per emissions year / Tg per 100 200 year 50 100 0 0 fossil agriculture biomass wetland other chemical soils fuel and drainage natural reaction in production biofuel sources atmosphere production sink source Fig. 1.1 (i) Complete the bar for agriculture to show a value of 205 Tg per year. [2] (ii) The total methane emissions are 735 Tg per year. Calculate the difference in total emissions and total removal of methane. … Tg per year [1] (iii) Suggest two sources included within ‘other natural sources’ in Fig. 1.1. 1 … 2 … [2] (iv) Suggest three reasons why different computer models may give different values for methane removal. 1 … … 2 … … 3 … … [3] [Total: 10]

10 marks

Mark scheme: Question Answer Marks 1(a)(i) (gas that) absorbs infrared radiation; 1 1(a)(ii) explosion; 1 1(b)(i) M1 bar plotted at 205; 2 M2 same width and same gap between bars; 1(b)(ii) 110; 1 1(b)(iii) any two from: 2 M1 permafrost (melting); M2 oceans (outgassing); M3 decaying vegetation; M4 animals (waste or respiration); M5 volcanoes (outgassing or erupting); 1(b)(iv) any three from: 3 M1 different variables (fed into different models); M2 uncertainty over data (input or output); M3 feedback mechanisms not fully understood; M4 not all sources or sinks are known; M5 differences in technologies or advancements;

This question in 8291/21 Oct/Nov 2025

4 (a) Fig. 4.1 shows a mayfly nymph in a river. Fig. 4.1 A student wants to sample the population of mayfly nymphs in a river. Fig. 4.2 shows the river. Fig. 4.2 (i) Suggest two safety precautions the student should take before using this river to sample mayfly nymphs. 1 … … 2 … … [2] (ii) Describe how kick sampling is used to investigate the population of mayfly nymphs in the river. … … … … … … … … … … [5] (b) The population of mayfly nymphs in river water is used as an indication of water quality. Fig. 4.3 shows data for the population of mayfly nymphs in rivers in an area of India. 100 90 80 70 60 population of 50 mayfly nymphs 40 30 20 10 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec month Fig. 4.3 Fig. 4.4 shows data for the mean monthly pH of water from the same rivers in India. 10 9 8 7 6 water pH 5 4 3 2 1 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec month Fig. 4.4 The student concludes that a water pH value of 7 provides the best conditions for mayfly nymphs. Discuss whether this conclusion is correct. … … … … [2] (c) Acid deposition can affect aquatic environments. (i) Outline the formation of acid deposition from the combustion of fossil fuels. … … … … … … … … [4] (ii) State two impacts of acid deposition other than on aquatic environments. 1 … … 2 … … [2] [Total: 15]

15 marks

Mark scheme: 4(a)(i) any two from: 2 M1 consider safe access; M2 know the depth; M3 (know the) structure of river bed; M4 (know the) flow or velocity of water; M5 (know the) direction of water flow; M6 (know the) weather forecast / risk of flash flooding; M7 wear appropriate or protective clothing; e.g., closed shoes or boots / gloves 4(a)(ii) any five from: 5 method of disturbance: M1 disturb or kick, riverbed; M2 disturb or kick for stated period; method of sampling: M3 use systematic or random sampling of site / or method described; location: M4 sample collected downstream of disturbance; M5 (opening of) net facing upstream; method of counting and processing: M6 idea of decanting sample into bucket; M7 identify mayfly nymph and count sample; M8 repeat and average (at same location); M9 repeat and average at different, times / location; 4(b) any two from: 2 M1 yes and highest abundance in May and pH 7; M2 no and September low abundance and pH 7; M3 no and other factors also influence abundance; 4(c)(i) any four from: 4 M1 deposition can be wet or dry; M2 fossil fuels contain sulfur (compounds); M3 (combustion of fossil fuels) releases sulfur dioxide or SO2 gas; M4 (sulfur dioxide or SO2) reacts with water and oxygen; M5 forms, sulfuric acid / H2SO4; 4(c)(ii) any two from: 2 M1 defoliation / loss of leaves (of plants or crops); M2 reduced crop yield; M3 (enhanced) chemical weathering; M4 damage to, limestone buildings / marble statues / metal structures; M5 (dry acid deposition) causes named health issue e.g., respiratory lung disease, asthma, bronchitis;

This question in 8291/21 Oct/Nov 2025

1 (a) Methane is a greenhouse gas. Greenhouse gases contribute to climate change. (i) Define the term greenhouse gas. … … [1] (ii) State one danger of a build-up of methane in the atmosphere other than climate change. … [1] (b) Computer models are used to estimate the global atmospheric methane budget measured in teragrams, Tg. 1 Tg = 1 × 109 kg. Sources add methane into the atmosphere and sinks remove methane from the atmosphere. Fig. 1.1 shows data for the global atmospheric methane budget. 600 250 500 200 400 mean global mean methane 150 300 global removal methane / Tg per emissions year / Tg per 100 200 year 50 100 0 0 fossil agriculture biomass wetland other chemical soils fuel and drainage natural reaction in production biofuel sources atmosphere production sink source Fig. 1.1 (i) Complete the bar for agriculture to show a value of 205 Tg per year. [2] (ii) The total methane emissions are 735 Tg per year. Calculate the difference in total emissions and total removal of methane. … Tg per year [1] (iii) Suggest two sources included within ‘other natural sources’ in Fig. 1.1. 1 … 2 … [2] (iv) Suggest three reasons why different computer models may give different values for methane removal. 1 … … 2 … … 3 … … [3] [Total: 10]

10 marks

Mark scheme: Question Answer Marks 1(a)(i) (gas that) absorbs infrared radiation; 1 1(a)(ii) explosion; 1 1(b)(i) M1 bar plotted at 205; 2 M2 same width and same gap between bars; 1(b)(ii) 110; 1 1(b)(iii) any two from: 2 M1 permafrost (melting); M2 oceans (outgassing); M3 decaying vegetation; M4 animals (waste or respiration); M5 volcanoes (outgassing or erupting); 1(b)(iv) any three from: 3 M1 different variables (fed into different models); M2 uncertainty over data (input or output); M3 feedback mechanisms not fully understood; M4 not all sources or sinks are known; M5 differences in technologies or advancements;

This question in 8291/23 Oct/Nov 2025