The Indian sub-continent may lose close to 14,000 sq.km. of land with the rise of a one metre of sea level due to climate change.
“Total area loss due to marine intrusion into coastal areas of the Indian sub-continent is estimated at approximately 13,973 sq.km. and 60,497 sq. km. of land area under 1m (metre) and 6m sea-level rise scenarios, respectively,” says a report published in the latest issue of Journal of Threatened Taxa.
Prepared by a group of ecologists led by Dr M Zafar-ul Islam, the study presents an overview of the potential consequences of 1m and 6m sea-level rise for coastal conservation areas on the Indian sub-continent.
Sea level is rising due to thermal expansion of the ocean, mountain glacier melting, and discharge from ice sheets as a result of global warming.
Several coastal eco-regions and conservation areas are predicted to lose over half of their land areas to marine intrusion, particularly under the 6m sea level rise scenario.
The report warns that marine intrusion might affect 18 of the 48 eco-regions in India.
“Under the 1m sea level rise scenario, estimates of eco-region inundation range from 19 per cent to 59 per cent. While under the 6m sea-level rise scenario, estimates of eco-region inundation range from 27-58 per cent,” it says.
Under the 1m sea level rise scenario, the Godavari-Krishna mangrove eco-region is predicted to lose more than a quarter of its area, while the UNESCO World Heritage site of Sundarbans in West Bengal is predicted to lose more than half of its area.
While under the 6m sea level rise scenario, three eco-regions (Sundarbans freshwater swamp forests, Andaman Islands rain forests and Maldives Lakshadweep-Chagos Archipelago tropical moist forest) are predicted to lose more than a quarter of their land areas.
Three more (Sundarbans mangroves, Godavari-Krishna mangroves, and Rann of Kutch seasonal salt marsh) are predicted to lose more than half of their land area.
Seven protected areas — Bhitarkanika, Chilka Lake, Point Calimere, Interview Island, Lothian Island, Sajnakhali and Pulicat Lake — are expected to experience more than 50 per cent inundation under 1m sea level rise, and an additional four protected areas — Kachchh Desert, Velavadar, Pulicat, and Nal Sarovar — join this list under 6m sea level rise.
Out of the 22 coastal conservation areas, nine will be spared from the effects of marine intrusion under 1m sea-level rise, but only one will be spared under a 6m sea-level rise scenario, says the report.
Hundreds of species of flora and fauna, including globally threatened species, depend upon low-lying coastal eco-systems for their survival.
Several important biodiversity areas, including in particular protected and non-protected IBAs (Important Bird Areas) in the Bay of Bengal and Arabian Sea, have already been stressed by numerous anthropogenic impacts as well as by invasive species.