IGCSE Environmental Management Past Papers & Drilling (Paper 1): Energy, Soil, Water and Air

Question 1

(a) Years of coal = 4800 / 160 = 30 years. (4 marks)

(b) Low-carbon share = 8% + 30% = 38%, still below the 62% from fossil fuels combined. (4 marks)

(c) Hydraulic fracturing needs large volumes of water and chemicals, so groundwater can be contaminated; flowback fluids and methane leakage add greenhouse gases; operations can also trigger minor earthquakes, use scarce water and damage surface habitats. (any two, 6 marks)

(d) Removing subsidies closes the cost gap between fossil fuels and renewables immediately, but can raise electricity prices and meet political resistance; a renewable quota guarantees capacity and demand within a set period but needs grid investment and back-up capacity. Used together they change both price signals and supply structure, whereas a single tool tends to shift emissions elsewhere. (6 marks)

Question 2

(a) Net erosion = 12.0 – 0.8 = 11.2 tonnes per hectare per year; over 20 years the loss is 11.2 x 20 = 224.0 tonnes per hectare. (5 marks)

(b) Topsoil mass = 0.15 x 1.35 x 1000 = 202.5 kg/m2; annual loss = 12.0 / 10 = 1.2 kg/m2, so complete loss would take 202.5 / 1.2 = about 169 years. (5 marks)

(c) Yield gap = (6.8 – 5.2) / 6.8 x 100 = about 23.5%. (3 marks)

(d) Contour ploughing cuts slope length and slows runoff, reducing sheet and rill erosion; cover crops protect the surface in fallow periods and raise organic matter and infiltration. Both are cheap and easy to spread, yet they give limited protection on steep slopes and in extreme storms, so they need terracing, grass strips and reduced tillage alongside them – and farmers may resist the extra labour and short-term yield loss. (7 marks)

Question 3

(a) Water per person = 3.2 x 10^9 / 2,400,000 = about 1333 m3 a year, below the 1700 m3 threshold, so the area is water stressed. (5 marks)

(b) Effluent BOD = 320 x (1 – 0.85) = 48.0 mg per litre; after mixing = (0.5 x 48.0 + 8.0 x 2.0) / (0.5 + 8.0) = about 4.7 mg per litre. (6 marks)

(c) Share = 8 / 400 x 100 = 2.0%. (3 marks)

(d) Tertiary treatment removes nitrogen, phosphorus and pathogens and can bring effluent up to reuse standards, but it is energy-intensive and costly, which low-income regions struggle to fund; cutting plastic at source (single-use bans, producer responsibility, deposit return) is more cost-effective and reduces both ocean plastic and microplastics, yet depends on enforcement and collection infrastructure. The two belong together: clean the end of the pipe while cutting what enters it. (6 marks)

Question 4

(a) Rise = (1900 – 700) / 700 x 100 = about 171.4%. (4 marks)

(b) Emissions after the cut = 12.0 x (1 – 0.40) = 7.2 million tonnes. (4 marks)

(c) Depletion = (300 – 220) / 300 x 100 = about 26.7%. (4 marks)

(d) 0.4 / 1.1 x 100 = about 36.4%. A mitigation example (cutting methane): repairing leaks in gas pipelines and wells, capturing landfill gas and changing rice paddy irrigation. Because methane has a much higher hundred-year warming potential than carbon dioxide, cutting it slows warming quickly, but leak rates need continuous monitoring and mandatory disclosure or the reduction stays on paper. (8 marks)

Question 1

Annual extraction per hectare = 2,400,000 / 320 = 7500 tonnes per hectare per year; restoration progress = 96 / 320 x 100 = 30%. Restoration must be staged during extraction, otherwise bare slopes increase soil loss and dust pollution.

Question 2

Irrigation efficiency = 3360 / 4800 x 100 = 70%. Improvements include drip or micro-spray irrigation, soil-moisture sensors that water on demand, and irrigating early in the morning to cut evaporation losses.