Population and the Environment

Explain why the mid-latitude grasslands support productive agriculture and dense rural populations, while tropical rainforest soils often do not.

1. 01The grassland soils

   The mid-latitude grasslands developed deep, dark, humus-rich chernozem soils under grass, with a moderate climate and a distinct growing season - highly fertile for cereals.

2. 02The rainforest soils

   The rainforest's constant heat and heavy rain leach nutrients from the soil (latosols) and hold the nutrients in the biomass, so the soils are surprisingly infertile once cleared.

3. 03The population link

   So the grasslands can sustain productive, dense farming populations, while cleared rainforest quickly loses fertility - climate and soil together set the agricultural and demographic potential.

Result: Fertile, humus-rich grassland soils under a suitable climate support dense farming, whereas leached, infertile rainforest soils cannot - so climate and soil jointly set the potential for population.

A country has 30 per cent of its population aged 0-14, 6 per cent aged 65 and over, and 64 per cent aged 15-64. Calculate the dependency ratio and explain what it shows.

1. 01Add the dependants

   Dependants = young + old = 30 + 6 = 36 per cent.

2. 02Apply the formula

   Dependency ratio = (dependants / working age) x 100 = (36 / 64) x 100.

   $$\dfrac{36}{64} \times 100 = 56.25$$
3. 03Interpret

   About 56 dependants per 100 workers; because the young (30 per cent) far outnumber the old (6 per cent), this is a youthful population with a high child-dependency burden - demand for schooling and child healthcare.

Result: The dependency ratio is about 56; the high proportion of children means a youthful population with a heavy child-dependency burden.

A region's population is growing rapidly and its food output is under strain. Explain how a Malthusian and a Boserupian would each predict the outcome.

1. 01The Malthusian view

   Population is growing geometrically while food can only grow arithmetically, so the region will reach a ceiling where food cannot feed everyone, and positive checks (famine, disease) will cut the population back.

2. 02The Boserupian view

   The pressure of rising numbers and food scarcity will drive farmers to intensify and innovate - new crops, irrigation, fertilisers - raising food output to keep pace with the population.

3. 03The judgement

   The actual outcome depends on whether innovation and investment can be mobilised in time and whether resources and distribution allow it - so neither prediction is inevitable, and the result is place- and time-specific.

Result: The Malthusian predicts a checked catastrophe; the Boserupian predicts innovation keeping pace - the real outcome depends on the region's capacity to innovate and distribute food.

The world produces enough food in total to feed everyone, yet many people are food insecure. Explain how this is possible.

1. 01Availability is not enough

   Food security requires not just that enough food is produced, but that people can actually access it - physically and financially.

2. 02Access barriers

   Poverty prevents people buying food; poor infrastructure and conflict block distribution; and food is unevenly spread between and within countries.

3. 03Conclusion

   So hunger persists amid plenty because it is a problem of access, distribution and poverty as much as of production - raising output alone does not reach those who cannot obtain the food.

Result: Enough food exists globally, but poverty, poor distribution and unequal access mean many still cannot obtain it - food insecurity is a problem of access, not only production.

Explain why malaria is concentrated in tropical regions and why its impact is greater in poorer countries.

1. 01The physical control

   The malaria parasite is spread by the Anopheles mosquito, which needs warm temperatures and standing water to breed, so transmission is confined to warm, wet tropical and subtropical regions.

2. 02The human control

   Within those regions, poverty, poor housing and drainage increase exposure, while wealthier areas can drain breeding sites, provide treated nets, drugs and health care to reduce transmission.

3. 03The combined outcome

   So the environment sets where malaria can occur, but development and poverty determine how heavily it strikes - which is why the burden falls disproportionately on poorer tropical populations.

Result: Warmth and standing water confine malaria to the tropics (physical), while poverty and weak control raise its burden in poorer countries (human) - the two factors together explain its distribution.

A wealthy country with an ageing population considers raising the retirement age, encouraging immigration and offering incentives to raise the birth rate. Evaluate these responses.

1. 01The problem

   Low birth rates and rising life expectancy raise the old-age dependency ratio, increasing pension and care costs and shrinking the workforce.

2. 02Assess the responses

   Raising the retirement age keeps people working longer but is unpopular and unequal in effect; immigration can fill labour gaps quickly but raises political and integration issues; pro-natalist incentives act only slowly and are often weakly effective.

3. 03Reach a judgement

   No single measure solves the problem; a combination is needed, and each involves economic and social trade-offs - so a defensible conclusion is that ageing is manageable but only through a balanced package, not a single policy.

Result: Each response (later retirement, immigration, pro-natalism) helps but has trade-offs and none suffices alone, so managing ageing requires a balanced combination.