waterSecurity
An important problem already affecting numerous coastal areas including small islands is salt water infiltration in soils or salinisation, especially on atoll countries such as Tuvalu, Maldives, or Kiribati.
Atolls get their freshwater supplies from rainfall or groundwater (rainfall filtered in the ground). Freshwater is lighter than salt water; a lens is formed under the atoll with freshwater on top. This reserve of freshwater is vulnerable to decrease in rainfall (as the lens cannot replenish) and over drilling which can contaminate the lens water with brackish water.
Freshwater lens. (Source: UNESCO Portal)
As projections from the IPCC have shown, there is strong evidence that water resources and distribution of rainfall on small islands will be compromised with climate change. In Kiribati, for instance, a 10% reduction in average rainfall by 2050 would lead to a 20% reduction in the size of the freshwater lens. In addition, increase frequency of extreme weather events, sea level rise and resulting land loss, are likely to increase the stress on freshwater lens on atolls. For example, studies in Tarawa, Kiribati, demonstrated that a 50 cm rise in sea level accompanied by a reduction in rainfall of 25% would reduce the freshwater lens by 65%.
These negative impacts of climate change cumulated with population increase put the availability of fresh water resources at risk. Water quality is likely to be degraded by salt water infiltration. This could lead to health problems related to the scarcity of freshwater, and to the spread of water born diseases. As freshwater runs scarce, life on islands will be more difficult to sustain. The inhabitants of the Carteret islands in Papua New Guinea are currently suffering increase water shortage and rely on coconut water since average precipitations have decreased and their freshwater supplies have been contaminated by saltwater infiltration.
Salt water infiltration has also severe adverse impacts on agricultural practices. As salt water infiltrates the aquifers and soils, many salt intolerant traditional crops, such as taro or pulaka, die from salt contamination, which affects the traditional diet of islanders. For example, across the Pacific, taro crop is a fundamental element of islanders’ diet. Because of salt contamination in soils, many island communities have been forced to relocate their plantations further inland or in higher grounds. For atolls, which culminate at less than 5 meters above sea level, the situation is even more precarious: some island communities, in Tuvalu for instance, have started growing traditional crops in tin cans since they are unable to relocate to higher grounds. Other communities are switching to salt resistant crops. However, these are expensive or difficult to obtain. Indeed, some require genetic modification to adapt to saline soils (tomato, rice), or others are not part of the traditional diet of the islanders. The implantation of such crops is, thus, modifying the diet and culture of islanders around the world.
Similarly, the import of foreign goods/foods (such as rice) to palliate the scarcity of locally grown goods from increased soil salinity has not erased all problems. Islands are often removed from major centers. As a result, these imported foods are often expensive and take time to be shipped to these islands. Therefore, the risk of food scarcity is a threat that constantly looming over islands’ communities.