Assess the impact of global warming on the coral life system with examples.
Approach · directive: “assess”
What it asks · Assess how rising sea temperature and related ocean changes damage coral reef ecosystems, with named reefs and events, and what follows for people and coasts.
The question has 3 parts — answer each
- Assess the impacts of global warming on coral reef systems: bleaching, acidification, storms and loss of recovery time
- Support the assessment with examples, global and Indian
- Bring out what follows for marine life, people and coasts
Open with · Corals live near their upper thermal limit; a sustained rise of about 1°C above the local summer maximum triggers bleaching, making reefs early casualties of global warming.
Cover
- Bleaching: heat stress makes corals expel symbiotic algae; mass bleaching in 1998, 2010 and 2014–17 hit reefs worldwide, including the Great Barrier Reef.
- Ocean acidification: absorbed carbon dioxide lowers carbonate availability, weakening skeletons and slowing reef growth, especially when bleaching repeats.
- Other stresses: sea-level rise, stronger cyclones and disease outbreaks; shorter gaps between heat events leave too little time for recovery.
- Indian examples: bleaching has been recorded on reefs of the Andaman and Nicobar Islands, Lakshadweep and the Gulf of Mannar in warm El Niño years.
- Ecological chain: loss of reef structure removes habitat for fish, hurting fisheries, tourism income and the natural shoreline protection of island and coastal communities.
- Shifts and thresholds: algae-dominated reefs replace coral, biodiversity falls, and recovery may not occur if warming continues; local pollution and destructive fishing add to stress.
- Response: emission cuts, marine protected areas, cleaner coastal waters, sustainable fishing, and restoration or research on heat-tolerant corals.
Close with · Only deep emission cuts, together with cleaner coastal waters and protected reefs, can give corals a chance to recover between heat events.
Question: UPSC's CS (Main) 2019, GS Paper I — paper ↗. Approach: Minimalist IAS, checked 30 Sept 2026 (how we verify) — UPSC publishes no model answers. ·
Model answer · 227 words (UPSC limit 150) · Minimalist IAS
Reef-building corals live close to their upper temperature limit: a sustained rise of about 1°C above the local summer maximum triggers bleaching, which makes reefs among the earliest casualties of global warming.
Impacts on the coral system
- Bleaching: heat stress makes corals expel their symbiotic algae, lose colour and starve; if the heat persists they die. Mass bleaching struck reefs worldwide in 1998, 2010 and 2014-17, including the Great Barrier Reef.
- Acidification: the ocean absorbs carbon dioxide, carbonate becomes scarcer, skeletons weaken and reef growth slows, compounding bleaching damage.
- Storms, sea level and disease: stronger cyclones break reef structure, rising seas and disease add stress, and shorter gaps between heat events leave too little time to recover.
- Regime shift: repeatedly bleached reefs turn algae-dominated and lose biodiversity; pollution and destructive fishing hasten the shift.
Indian examples
- Bleaching has been recorded in the Gulf of Mannar, Lakshadweep and the Andaman and Nicobar Islands in warm El Niño years, so India's reefs follow the global pattern.
What follows for people and coasts
- Loss of reef structure removes fish habitat, cutting fishery yields and tourism income, and strips island and coastal communities of a natural breakwater against surge and erosion.
Only deep emission cuts can end the heat events; meanwhile cleaner coastal waters, protected reefs, sustainable fishing and research on heat-tolerant corals give reefs a chance to recover between them.
Written by Minimalist IAS from facts checked at source (how we verify) — a little fuller than exam length, so every part of the question is covered; in the hall, keep the structure and trim the detail. UPSC publishes no model answers: compare your structure and coverage with this, then write your own.