People, Development and Environment
People, Development and Environment
This domain joins ecology and pollution with development indicators and international agreements - roughly a tenth of Paper I.
Ecology and pollution
- Ecosystem components: producers, consumers, decomposers; energy flows one way while nutrients cycle (carbon, nitrogen, phosphorus).
- Ecological pyramids: numbers, biomass, energy; the energy pyramid is always upright.
- India's biodiversity hotspots (four): Himalaya, Western Ghats–Sri Lanka, Indo-Burma, Sundaland (Nicobar Islands).
- Ozone depletion is caused by CFCs and halons and is governed by the Montreal Protocol (1987); global warming is driven by CO₂, CH₄, N₂O and F-gases under the UNFCCC (1992), Kyoto Protocol (1997, binding targets for Annex-I) and Paris Agreement (2015, NDCs for all parties).
- Indian statutes: Water Act 1974, Forest Conservation Act 1980, Air Act 1981, Environment (Protection) Act 1986, Biological Diversity Act 2002, National Green Tribunal 2010.
Development
HDI (UNDP, from 1990; devised by Mahbub ul Haq with Amartya Sen) is the geometric mean of three dimension indices: health (life expectancy), education (mean and expected years of schooling), and standard of living (GNI per capita, PPP). Sustainable development was defined by the Brundtland Report (1987); the 17 SDGs replaced the MDGs in 2015, and NITI Aayog publishes the SDG India Index.
Worked example
If a country's GNI per capita doubles, its income index does not double. Income enters HDI after a logarithmic transformation against goalposts, so equal absolute gains matter more at low income - a deliberate design to stop rich countries dominating the index.
Traps
- Blaming CO₂ for the ozone hole, or CFCs for warming.
- Confusing Kyoto (Annex-I targets) with Paris (universal NDCs).
- Treating HDI as an arithmetic mean; it is geometric.