Core: Global resource consumption and security practice questions.

A national ecological footprint is reported in global hectares per person. What does that figure measure?

• The bioproductive area needed to supply consumption and absorb waste
• The total land area of the country divided by its population
• The area of farmland used to grow the food one person eats each year
• The share of a country's territory that has been degraded by human activity

Answer: The bioproductive area needed to supply consumption and absorb waste

The footprint converts every demand - cropland, grazing, forest products, built land and the forest needed to absorb carbon emissions - into one standardised productive area, which is why it can exceed the area a country actually owns.

In many semi-arid farming regions groundwater is lifted for irrigation by electric pumps, and the power stations supplying them need cooling water. Which idea does this best illustrate?

• Resource substitution, in which one resource simply replaces another
• The water-food-energy nexus of interdependent resource demands
• The demographic transition, in which resource use falls as families shrink
• Resource stewardship, in which resources are managed for future generations

Answer: The water-food-energy nexus of interdependent resource demands

The nexus idea is that securing one resource raises demand for the others, so a policy that solves food security by expanding irrigation can quietly create an energy and a water problem at the same time.

In 2022 the World Bank updated its international extreme poverty line to US$2.15 a day expressed in 2017 purchasing power parity terms. Why is the line stated in PPP dollars rather than at market exchange rates?

• PPP removes the effect of inflation between one year and the next
• PPP converts incomes into the currency of the country with the largest economy
• PPP measures the income of the middle class rather than of the poorest
• PPP adjusts for differences in what a dollar actually buys in each country

Answer: PPP adjusts for differences in what a dollar actually buys in each country

Non-traded goods such as housing, food staples and local services cost far less in lower-income economies, so a market exchange rate would overstate poverty there; PPP standardises purchasing power before the threshold is applied.

Since the 1960s the Aral Sea in Central Asia has lost most of its volume. Which change in resource use is the main direct cause?

• Diversion of the Amu Darya and Syr Darya for cotton irrigation
• A permanent fall in regional precipitation caused by global warming
• Increased evaporation from the building of hydroelectric reservoirs
• Over-abstraction of groundwater by expanding cities on the lake shore

Answer: Diversion of the Amu Darya and Syr Darya for cotton irrigation

The inflow rivers were tapped for irrigated cotton and rice, so the lake's water budget lost its input while evaporation continued; the exposed bed now supplies salt and pesticide-laden dust storms, a second-order impact of the same decision.

Discarded electronic equipment from high-income countries is dismantled in informal workshops in cities such as Accra, Ghana. Which combination of impacts is most characteristic of this trade?

• Higher recycling rates together with strict enforcement of workplace safety law
• Rising formal recycling capacity in Ghana together with falling global metal prices
• Income for informal workers together with heavy-metal contamination of soils
• Reduced demand for new devices and rising formal-sector employment

Answer: Income for informal workers together with heavy-metal contamination of soils

Burning cable insulation to recover copper releases dioxins and leaves lead and cadmium in the soil, yet the trade is also a livelihood; the impacts of consumption fall on people who never consumed the devices, which is the power dimension of waste flows.

Bitumen from the Athabasca oil sands in Alberta, Canada must be mined or heated with steam before it can be upgraded into synthetic crude oil. Compared with conventional light crude, what does this imply?

• More energy and more water are used per barrel produced
• Less energy is used per barrel because the deposit lies near the surface
• Emissions per barrel are lower because no drilling rig is needed
• The resource is renewable because bitumen re-forms in the deposit

Answer: More energy and more water are used per barrel produced

Bitumen is too viscous to flow to a well, so it has to be strip-mined or mobilised underground with injected steam and then upgraded, and those steps burn natural gas and use large volumes of water. Each barrel therefore carries higher energy, water and emissions costs than conventional light crude, and the deposit, formed over geological time, is non-renewable.