Context: Recent scientific research using coral microatolls has revealed that sea-level rise (SLR) in the central Indian Ocean, particularly around the Maldives, Lakshadweep, and Chagos Archipelago is accelerating. Earlier studies suggested that significant acceleration started only in the 1990s, but new evidence shows that seas in this region have been rising since the late 1950s.
Relevance of the Topic: Mains: Implications of Climate Change.
Rising Sea Levels in Indian Ocean
- Rising sea levels are among the most visible and threatening consequences of global warming. The Indian Ocean, which is the third largest ocean basin in the world, has been experiencing sea-level rise at an accelerated pace.
- The Indian Ocean’s levels have been rising at around 3.3 millimetres per year, which is higher than the global average, which in turn amplifies changes in ocean dynamics and atmospheric circulation.
- These shifts have a direct impact on coral reefs, fisheries, and low-lying island nations such as the Maldives, Lakshadweep, and the Chagos Archipelago.
Key Findings of the Study:
A team of researchers from the National University of Singapore studied coral microatolls in the Maldives. The study reconstructed sea-level history from 1930 to 2019, extending the existing records by nearly 90 years. The findings showed that :
- Sea levels rose by around 0.3 metres over the 90-year period.
- The rate of rise has accelerated over time: it was between 1 and 1.84 mm/year from 1930 to 1959, and between 3.91 and 4.87 mm/year from 1990 to 2019. This indicates that sea-level rise in the Indian Ocean began accelerating in the late 1950s.
- The periods of coral growth interruption coincided with El Niño events, negative Indian Ocean Dipole events, and the 18.6-year lunar nodal cycle, all of which influence sea levels and stress corals.
Implications of Rising Sea Levels:
- Ecological: Coral reefs face bleaching due to reduced sunlight, warmer waters, and acidification, threatening biodiversity and marine productivity.
- Human & Economic: Low-lying islands risk inundation; livelihoods from fisheries and tourism are endangered; flooding, erosion, and storm surges increase vulnerability.
- Geopolitical & Security: Strategic islands like Maldives and Lakshadweep face displacement, migration, and sovereignty challenges, impacting maritime trade and security.
Way Forward
- Strengthening Scientific Monitoring: Expanding tide gauge networks, improving satellite observations, and using natural recorders such as coral microatolls can help fill critical gaps in sea-level data, and thus improve the accuracy of climate models and projections.
- Ecosystem-Based Adaptation: Restore mangroves, seagrasses, and coral reefs as natural buffers.
- Policy & Governance: Integrate sea-level rise into planning and disaster frameworks; secure climate finance and technology for island nations.
- Resilient Infrastructure: Build climate-proof housing, elevate infrastructure, and strengthen flood protection.
- Regional & Global Cooperation: Use IORA, UNFCCC, and regional platforms for joint monitoring, data sharing, and coordinated adaptation.