Case studies

China

  • China's One-Child Policy, implemented in 1979, was a strict anti-natalist policy designed to control rapid population growth. The policy restricted urban couples to having only one child, with exceptions for rural families if their first child was a girl or had disabilities, and for ethnic minorities.

  • To enforce this, the government used a combination of incentives and penalties:

    • Incentives: Families complying with the policy received benefits such as free education, healthcare, and priority housing.

    • Penalties: Violators faced fines, reduced employment opportunities, and loss of social benefits. In extreme cases, forced sterilizations or abortions occurred.

    • Enforcement: Local authorities, including the "Granny Police," monitored compliance, ensuring adherence through community surveillance.

  • The policy also included specific measures like raising the legal marriage age and requiring permits for childbirth. By the 2000s, it had significantly reduced China's fertility rate from 5.9 (1960s) to 1.6 (2016). However, it was relaxed in 2016 due to aging population concerns.

  • Impacts

  • China's One-Child Policy was put into place in 1980 and relaxed in 2016, as the government was anti-natal and aimed to reduce the population growth. By setting up incentives such as free education and easiness to find jobs and disincentives such as penalties and forced abortion, the fertility rate dropped from 5.9 in the 1960s to 1.6 in 2016. The strict enforcement lead to several issues: gender imbalances as well as an ageing population.

  • The annual babies born was also decreased, from 26.9 million on average per year between 1949 - 1957 before the policy to 15.84 million on average per year between 1981 - 1990 after the policy. The policy was relaxed in 2016 due to concerns on an ageing population as by 2023, 20% of China's population is over 60 and is projected to be 38% by 2050 and the fertility rate dropped further to 1.09 in 2023 and the annual birth fell from 18 million in 2016 to 9 million in 2023.

  • 90% of abandoned babies are girls due to gender preference. Due the shortage of women, 25% of men aged between 25-45 will never marry. The healthcare for elderly is projected to be 15% of GDP by 2050. Employment is also affected due to the ageing population, such as the Guangdong labour shortage.

Eyjafjallajökull

  • The 2010 eruption of Eyjafjallajökull in Iceland was caused by its location on a constructive plate boundary, where the North American and Eurasian plates diverge. As the plates moved apart, magma rose from the mantle to fill the gap, creating pressure beneath the volcano.

  • Key processes triggering the eruption:

    • Plate Movement: The plates separated at the Mid-Atlantic Ridge, allowing magma to pool in the magma chamber.

    • Pressure Build-Up: Increasing magma pressure fractured the overlying rock, creating a vent.

    • Subglacial Eruption: Eyjafjallajökull’s ice cap melted upon contact with magma, causing explosive phreatomagmatic eruptions (steam-driven blasts).

    • Place-Specific Detail: The eruption began on 20 March 2010 (fissure eruption) and escalated on 14 April (explosive summit eruption), producing an ash cloud reaching 9 kmhigh.

Hong Kong

  • Hong Kong, a densely populated urban area with limited natural freshwater resources, employs a multi-faceted approach to supply clean water for domestic use:

    • Dongjiang River Imports (Guangdong, China):

      • 80% of Hong Kong’s water is imported from the Dongjiang River under a long-term agreement with Guangdong Province.

      • Water is treated locally in Hong Kong’s treatment plants (e.g., Pak Kong Water Treatment Works) to meet WHO standards.

    • Reservoirs and Catchment Systems:

      • 17 reservoirs (e.g., Plover Cove, one of the world’s largest sea-fed reservoirs) store rainwater collected from protected catchment areas.

      • Accounts for 20–30% of supply, depending on rainfall.

    • Seawater Flushing:

      • Unique seawater flushing system (covering 80% of households) reduces freshwater demand for toilets, saving 750,000 m³/day.

    • Desalination:

      • Tseung Kwan O Desalination Plant (opened 2023) produces 135,000 m³/day using reverse osmosis, boosting drought resilience.

Niger

  • Niger, with the highest fertility rate globally (6.7 births per woman) and a population doubling every 20 years, faces severe challenges due to rapid growth:

    • Food Insecurity:

      • Over 80% of land is arid, yet agriculture employs 80% of the population. Overcrowding leads to overgrazing and soil degradation, worsening droughts (e.g., 2023 crisis left 3.3 million food-insecure).

    • Urban Squatter Settlements:

      • Capital Niamey’s population grows by 4.3% annually, forcing 60% of residents into informal settlements like Lazaret with no clean water or sanitation.

    • Pressure on Education:

      • Only 56% of children attend primary school due to overcrowded classrooms (e.g., 100:1 student-teacher ratios in rural areas like Zinder).

    • Water Scarcity:

      • 42% lack clean water access; the Niger River is overused, with pollution from untreated sewage (e.g., cholera outbreaks in Maradi, 2022).

    • Deforestation:

      • 100,000 hectares of forest lost yearly as families cut trees for fuel, accelerating desertification in regions like Tahoua.

Ganges

  • The Ganges River in India and Bangladesh frequently floods due to a combination of natural and human factors:

    • Heavy Monsoon Rainfall:

      • The Ganges Basin receives 80% of its annual rainfall during the monsoon season (June–September). In 2020, Bihar recorded 1,500 mm of rain in 3 weeks, overwhelming the river’s capacity.

    • Himalayan Snowmelt:

      • Rising temperatures accelerate glacial melt from the Gangotri Glacier, increasing discharge downstream.

    • Deforestation in the Terai Region:

      • 25% of Nepal’s forests have been lost since 1990, reducing interception and increasing surface runoff into tributaries like the Ghaghara River.

    • Urbanization and Poor Drainage:

      • Cities like Patna and Dhaka have concretised 60% of land, preventing infiltration. Clogged drains worsen flooding (e.g., 2019 Patna floods reached 2m deep).

    • Sedimentation and Siltation:

      • The Ganges carries 1.8 million tonnes of sediment annually, raising its bed and reducing channel capacity.

Hurricane Haiyan

  • Typhoon Haiyan (locally called Yolanda), which struck the Philippines on November 8, 2013, with winds of 315 km/h (one of the strongest ever recorded).

  1. Human impacts

  • Deaths & Injuries: Over 6,300 killed, 28,000 injured.

    • Place-specific: Tacloban City saw 90% of structures destroyed; storm surges reached 5 meters.

  • Displacement: 4 million homeless, with 1.9 million in evacuation centers (UN data).

  1. Infrastructure Damage

  • Buildings: 1.1 million houses damaged (half totally destroyed).

  • Transport: Roads/bridges collapsed in Eastern Visayas, isolating towns for weeks.

  • Utilities: Power outages lasted months in rural areas like Samar Island.

  • Guiuan: First hit→95% of buildings gone in minutes.

  • Samar Island: Isolated for 3 weeks due to blocked roads.

  • Tacloban Airport: Smashed by shipping containers flung by winds.

  1. Economic & Environmental Impacts

  • Agriculture: Rice fields in Leyte province flooded with saltwater, ruining crops.

  • Fishing Industry: 30,000 boats destroyed, crippling livelihoods.

  • Ecosystems: Mangrove forests in Guiuan eroded, increasing future flood risks.

  1. Long-Term Consequences

  • Disease: Contaminated water led to cholera outbreaks.

  • GDP Loss: $12.9 billion in damages (5% of Philippines’ GDP).

Yemen

  1. Human Impacts

  • Starvation & Death:

    • 85,000+ children under 5 died from acute malnutrition (UN, 2023).

    • Place-specific: In Hodeidah, 1 in 5 children are severely malnourished.

  • Disease:

    • Cholera outbreaks (2.5 million cases since 2016) due to contaminated water.

  1. Economic & Social Collapse

  • Poverty: 80% of Yemenis live below the poverty line; many sell possessions for food.

  • Crime: Looting of aid trucks and food riots in Sana’a.

  • Child Labor: Kids skip school to beg/work for food.

  1. Long-Term Consequences

  • Land Overuse: Farmers grow only qat (a narcotic plant) for profit, worsening soil erosion.

  • Aid Dependence: 70% rely on WFP food aid, but blockades delay deliveries.

  • "Lost Generation": Malnourished children face stunted growth (30% under height).