The Island Nations: Life on Coral Atoll Islands in a World of Rising Sea Level


The Maldive Islands in the Indian Ocean and other low-lying island nations such as the Marshall Islands in the Pacific Ocean are the “poster children” for extreme sea level rise risk. Both nations are made up of numerous coral atolls, which each include several islands of varying sizes. They are all very low profile, with elevations usually of no more than two meters. They are currently facing multiple sustainability issues due to sea level rise. There is the simple issue of frequent tidal flooding and accompanying shoreline erosion, and then there are more complex problems related to saltwater intrusion into the freshwater lenses that the islanders depend upon for their drinking water. Chapter 8 of Jeff Goodell’s book, “The Water Will Come” discusses in detail the issues of the Marshall Islands. He says of the groundwater supply: “The problem is, as seas rise, the salt water pushes up from below, leaving less and less room for freshwater (which, being more buoyant, rides on top of the salt water). In addition, as the seas rise, flooding from storm surges is likely to become more common. When an atoll is inundated, the salt water can seep into the freshwater lens, contaminating it. It can take years before it is suitable for drinking again." (Goodell, 2017).

Meanwhile, the Maldive Islands, which comprise 1,200 islands on 26 atolls, faces similar challenges. In fact, the capital of the Maldives, Malé, sits on the most densely populated island in the world. As Figure 6.3 illustrates, the whole island is completely developed. Drinking water is desalinated by reverse osmosis using brackish groundwater, which is pumped from 50-60 meter wells. Malé is the center of all commercial activities of the Maldives. The main industry of the Maldives is tourism, comprising 28% of the nation’s GDP.  According to the United Nations Development Programme (UNDP) “Given that these reefs support both the country’s tourism and fisheries industries upon which the people depend almost exclusively, climate change is a profound threat to its very economic base.”

Understandably, the government leaders of the island nations such as the Maldives and the Marshall Islands have a great interest in how the world is addressing climate change, since they are on the front line in the sea level rise battle, with everything to lose, while contributing very little to the anthropogenic causes of climate change. The approach has been to work hard to get the attention of the rest of the world and push for policies that reduce greenhouse gas emissions. This has had limited success and caused plenty of frustration.

Malé, capital of Maldives.
Figure 6.3: Aerial view of the whole of Malé proper on the eponymous island as seen from the southwest.
Credit: By Shahee Ilyas [GFDL or CC-BY-SA-3.0, from Wikimedia Commons]
Map of Atolls in the Maldives
Figure 6.4: Geographic distribution of Atolls in the Maldives chain in the Indian Ocean.
Credit: This work has been released into the public domain by its author, Mohonu at the Wikipedia project. This applies worldwide.

The New Scientist article, On front line of climate change as Maldives fights rising seas, discusses recent developments in the efforts in the Maldives to plan for the future. One plan is to reclaim land by pumping sediment for relocation as sea levels rise. The article sheds light on some of the conflicts that arise, including the destruction of already threatened coral reefs by sediment pumped onto atolls to create new land. It also mentions the conflict for residents who are displaced by these activities.  In addition, there is an intriguing plan by the Saudi government with which the Maldives government is negotiating a lucrative deal to lease the Faafal Atoll for shipping security purposes. These activities reveal the extreme lengths to which a low-lying nation of islands must go if it is to survive a future of rising sea levels.

The National Geographic article, Reef islands can grow and change shape as sediments shift, studies show, linked from the Module 6 Road Map as required reading provides a very clear description of the situation for the island nations. It also addresses an interesting contribution to the conversation about the future of coral atoll islands from coastal geomorphologist Paul Kench, of the University of Auckland's School of Environment, and colleagues in Australia and Fiji, who have been studying how coral atoll islands respond to sea level rise. Their thesis is that, left in their natural state, coral atolls can grow and keep pace with sea level rise. They have measured this growth and reported that only 20% of the islands studied decreased in size during the time period considered. The islands that are heavily populated and altered by human infrastructure, not surprisingly, are the ones deemed unsustainable in terms of ability to naturally keep up with environmental changes.

Learn More about the Maldive Islands