Human Population, Resource Use and Environmental Impact: Water, Energy, Waste, Land Use and Pollution
Domain 3 examines how population size, consumption and technology create environmental pressure, and how that pressure shows up in Malta's water, energy, waste and land-use data. Expect arithmetic on per-capita rates and questions asking you to classify a pollution source or rank a management option.
Population and impact
- Demographic transition: high birth/death rates → falling death rates → falling birth rates → low/low, usually with an ageing population.
- Malta's 2021 Census recorded 519,562 residents in about 316 km² - roughly 1,600 people per km², among the highest densities in the EU. Recent growth is driven mainly by inward migration of foreign workers.
- I = P × A × T: impact = population × affluence (consumption per person) × technology (impact per unit consumed). Cleaner technology can cut T while P and A rise.
Malta's resource profile
- Water: around 500 mm rainfall with high evapotranspiration; the mean sea level aquifer is over-abstracted, so reverse osmosis supplies over half of potable water. Sewage polishing at Ta' Barkat and Sant' Antnin returns treated water.
- Energy: no indigenous fossil fuels; a gas-fired plant at Delimara plus the 2015 interconnector to Sicily; solar PV is growing but from a low base.
- Waste: hierarchy - prevent, reuse, recycle, recover (including energy), dispose. ECOHIVE at Magħtab, the Għallis landfill, bring-in sites and the beverage container refund scheme.
- Land use: development pressure on rural land, quarrying, road expansion, coastal squeeze.
Worked example
A household of three uses 110 L per person per day: 330 L/day × 365 = 120,450 L ≈ 120 m³ per year. A 100 m² roof collecting 500 mm at 80% efficiency yields 100 × 0.500 × 0.8 = 40 m³ per year, about a third of demand. The method - convert mm to metres, multiply by area, apply collection efficiency - answers any rainwater-yield question.
Traps that cost marks
- Miscoding sources: reverse-osmosis brine outfall is a point source; nitrate leaching from fields is diffuse.
- Quoting kg per capita per year when the question asks for total tonnes (multiply by population).
- Assuming an ageing population automatically reduces impact - per-capita consumption dominates.
- Treating "renewable" as automatically low-impact (land take, brine, embedded materials).