Lakshadweep may soon become uninhabitable, scientists warn

Lakshadweep islands are among the atolls that run the risk of becoming uninhabitable within decades because of regular heavy flooding of the islands by rising sea waves, damaging its freshwater sources, US scientists have warned.

Lakshadweep is not alone. A similar fate awaits Maldives and Seychelles too in the Indian Ocean beside several others in the Pacific such as the Marshall Islands, Caroline Islands, Cook Islands, Gilbert Islands, Line Islands, Society Islands and the Spratly Islands.

The annual flooding of these islands by waves, exacerbated by the rising sea, is likely to damage the freshwater resources in such a way that it would not be possible to live in many of these atolls that are a tourist paradise.

The flooding will also impact terrestrial infrastructure and habitats, but, more importantly, it will also make the limited freshwater resources non-potable and, therefore, directly threaten the sustainability of human populations.

The study carried out by scientists at the US Geological Survey in collaboration with four other institutes, predict it would not take more than a few decades to witness such overwash in many of these atolls.

The tipping point may come between 2030-2060, depending on the extent of climate change and global warming.

“Island inhabitants will be unable to rely on groundwater, in many cases the sole source of fresh water, as a source of potable water in the next few decades, and thus, the islands will be uninhabitable by the middle of the 21st century — not by the end of the 21st century or the middle of the 22nd century as previously suggested,” scientists reported in the April 25 issue of the journal Science Advances.

Andaman and Nicobar islands wouldn't be affected so badly. But their reef-fronted, low-lying coastlines and associated infrastructure, agriculture, and habitats will be negatively impacted by similar wave-driven flooding. The same has also been projected for Hawaii, Guam, American Samoa and Puerto Rico.

While the scientists focused on Roi-Namur Island on Kwajalein Atoll in the Republic of the Marshall Islands for their site study, they concluded that the findings have relevance to many other islands including Lakshadweep.

The primary source of freshwater for populated atoll islands is rain that soaks into the ground and remains there as a layer of fresh groundwater that floats on top of denser saltwater. The overwash events result in salty ocean water seeping into the ground and contaminating the freshwater aquifer.

"Rainfall is not enough to flush out the saltwater and refresh the island's water supply before the next year's storms arrive repeating the overwash events," explained Stephen Gingerich, USGS hydrologist and co-author of the study.