Coral reefs are highly productive, biodiversity rich but highly threatened underwater ecosystems. They are formed by symbiosis of polyps and zooxanthellae algae.
Impact of global warming on coral life systems:
1. Coral bleaching: Caused due to expulsion of the algae, due to which the polyps lose their nutrients and die out. E.g., Great Barrier reef bleaching, 2018.
2. Ocean acidification: Due to increased CO2 uptake by water bodies, reducing calcification and weakening of reef structures.
3. Extreme climatic events: Like storms, tsunamis which increase in duration and intensity. Eg 50% reduction in the Coral Triangle of Indonesia.
4. Sedimentation and land-based pollutants: Causes bleaching and reduces water clarity, lowering photosynthesis and growth.
5. Warming of surface water: Corals tolerate a narrow band of temperature; excessive warming can be growth inhibiting E.g., Caribbean reefs.
6. Increased sea levels may submerge coral islands like Maldives completely by 2100.
7. Loss of coral reefs bring environmental and economic challenges.
Global efforts aimed at sustainable development (SDG 13) together with limiting temperature rise to 2 degrees would be critical in saving the coral systems from imminent global extinction by 2050.