Small Island Nations' Freshwater Supplies in Danger

The first climate change refugees could likely come from small island states. Rising sea levels swallowing islands are often thought of as the culprit. However, island communities could disappear before the land does because of the absence of another key element to life: freshwater.

An estimated 50 million people inhabit over 8000 small islands around the globe. New research from the French Institute for Development Research (known by its French acronym IRD) shines a light on how fragile freshwater supplies are for a number of those people.

Many island communities rely heavily on lenses of freshwater that form in porous soils. For nations like the Maldives, Tuvalu, and Kirbati, which are located entirely on coral atolls, these lenses are the only sources of water for drinking, agriculture, and industrial activities. The lenses can form anywhere from 20 centimeters to 20 meters below the ground and sit atop a layer of saltwater. Their only source of recharge is rainfall.
Until now, the big picture of how the saltwater and freshwater interact and the recharge rates of lenses was still a mystery. IRD’s research shows that not all parts of a lens are created equal.
Contrary to what you might expect, researchers found that the concentration of saltwater was higher towards the center of the islands and not closer to the ocean. Upon further examination, they found plants were the cause. Islands tend to have more vegetation towards the center. They found that as the plants take up water and transpire it, more salts were left in the groundwater.
Salinity is also affected by freshwater lens recharge rates. The research shows the dense vegetation at the center of islands also contributes to lower recharge rates because the plants get first dibs on rainwater.
These factors can intersect with sea level rise to create a perilous situation for island communities. As the ocean covers the most readily rechargeable land, freshwater will dwindle. Without it, life will be impossible on small islands unless they invest in expensive desalinization equipment. Given that countries like the Maldives, Tuvalu, and Kiribati are classified as Least Developed Countries in the United Nations system, this would be next to impossible without funding from developed countries.
Combine this with the fact that parts of the South Pacific and Indian Ocean basins will likely see decreased rainfall due to climate change, and you’ve got a situation where a number of island nations can turn into ghost towns. The new research opens up the possibility for more detailed risk assessments of valuable freshwater resources. It also provides insights into possible techniques to preserve them for as long as possible while policymakers grapple with how to deal with climate refugees.
But as the Prime Minister of Samoa, Tuilaepa Sailele Malielegaoi, said at the Cancun climate talks, “Climate change for Samoa is not something that will happen in the future. We have already experienced destruction. We need to move quickly, rather than spend too much time talking." This new research gives even more precedence to that statement.
Photo Credit: Brian Kahn