Reliable access to freshwater is one of the fundamental pillars on which society is built. It is a necessary prerequisite for ensuring food security and a functioning system of public health. For Small Island Developing States, securing adequate freshwater supplies for drinking, sanitation, and agriculture is a constant challenge and climate change is only making it more difficult.
Rainfall is the primary source of freshwater for most islands. While seemingly plentiful in some regions, rainfall is not as dependable a source of water as, for example, land-based glaciers; something that low-lying and low latitude islands lack. Instead, SIDS must rely on surface water and groundwater supplies, which themselves are recharged by rainfall. However, these sources are threatened by climate change in a number of ways.
First, shifts in rainfall patterns are expected to increase the frequency and intensity of droughts in some regions. A single prolonged drought can have disastrous consequences on pluvial agriculture and can lead to the rapid depletion of an island’s surface and groundwater resources. Second, rising sea level is leading to saltwater intrusion into the groundwater supply. This is an especially serious problem for atoll islands, which a permeable and prone to flooding from within. Saltwater intrusion has already forced some islands to switch from traditional subsistence crops to more salt-tolerant varieties. Additionally, higher air temperatures lead to higher rates of water evaporation, reducing soil moisture and decreasing the rate of groundwater recharge.
There are few good options available to Small Island Developing States. Desalinization is energy intensive and expensive. Importing freshwater to remote islands is also expensive and not practicable for supporting any meaningful agricultural activity. Building new freshwater storage facilities can help extend supplies to a certain extent, but even they would likely prove inadequate in the face of a severe drought. | more