Assess the impact of global warming on the coral life system with examples.

Heat stress and bleaching

• When water stays about 1°C above the local summer maximum for weeks, corals expel zooxanthellae, turn white, and starve if the heat does not break.
• Mass bleaching hit the Great Barrier Reef in 1998, 2002, 2016, 2017, and later years, killing large stretches of shallow branching coral.
• El Niño years raise heat in the central and eastern Pacific and the Indian Ocean, which bleached reefs in the Maldives, Seychelles, Lakshadweep, and parts of Indonesia.
• India’s Gulf of Mannar, Andaman and Nicobar reefs, and Kachchh–Okha patches have recorded bleaching when the summer monsoon heat stays high.

Acidification, storms, and ecology

• Extra carbon dioxide makes seawater more acidic and lowers aragonite saturation, so skeletons of Acropora and other reef builders grow thinner and break more easily.
• Warmer seas feed stronger cyclones and wetter floods, which smash reefs and dump sediment and nutrients that let macroalgae take the space of coral.
• Disease and outbreaks such as crown-of-thorns starfish worsen on stressed reefs, which cuts fish nursery habitat and coastal protein.
• Some deeper or upwelling reefs bleach less, but they cannot replace the lost shallow system that protects islands and feeds artisanal fisheries.

Scale of reef damage

• The impact is not a slow even fade; it is repeated mortality pulses after marine heatwaves, with only partial recovery.
• Local sewage and overfishing make warming deadlier, so the coral life system fails first where heat and human pressure meet.