Flick a switch, fill a kettle, take a shower — three everyday actions that depend on two resources most of us never think about: energy and water. As countries develop and populations grow, demand for both soars, and how a nation meets that demand shapes its economy and environment.
Energy: renewable vs non-renewable
- Non-renewable (fossil fuels — coal, oil, gas — and nuclear) will run out; burning fossil fuels releases carbon dioxide.
- Renewable (solar, wind, hydro-electric, geothermal, tidal, biomass) will not run out and are mostly clean, but can be costly to build or intermittent.
| Source | Type | Main drawback |
|---|---|---|
| Coal | Non-renewable | Air pollution & CO2 |
| Nuclear | Non-renewable | Radioactive waste |
| Solar | Renewable | No power at night |
| Wind | Renewable | Only when windy |
| Hydro-electric | Renewable | Dams flood land |
Changing demand and the energy mix
Energy demand rises with population growth, industrialisation and higher living standards (more cars, appliances, air conditioning). A country's energy mix is the combination of sources it uses. Many countries are shifting from fossil fuels towards renewables to cut carbon emissions.
Water: supply, demand and scarcity
Water supply depends on rainfall, rivers, lakes and groundwater. Demand rises with population, farming (irrigation uses most of the world's water) and industry. Water scarcity occurs where demand exceeds reliable supply — either physical scarcity (not enough water, e.g. deserts) or economic scarcity (water exists but there is no money to access it).
Case study — the Three Gorges Dam, China
The Three Gorges Dam on the Yangtze River is the world's largest hydro-electric power scheme, a classic Cambridge water-management case study.
- Benefits: generates huge amounts of clean hydro-electricity, reducing coal use; controls flooding on the Yangtze that once killed thousands; allows larger ships further inland, boosting trade.
- Problems: the reservoir flooded towns and farmland, displacing over one million people; drowned historic and scenic sites; trapped sediment; and disturbed wildlife such as the river dolphin.
Water transfer schemes
Where water is plentiful in one area but scarce in another, water-transfer schemes move it by canal or pipeline (e.g. China's South–North Water Transfer Project). These help supply cities but are costly and can harm the source area.
Benefits: clean electricity cuts fossil-fuel use; flood control protects millions downstream; improved navigation boosts trade. Costs: over one million people displaced; farmland and heritage flooded; ecosystems damaged. Judgement: the dam brings large-scale power and flood protection, but at a heavy social and environmental cost — a strong answer reaches a supported conclusion.