Pacific islands may be starved of water

Some Pacific islands may be starved of fresh water by the end of this century if a rain band that affects nearly a billion people continues to migrate north, according to research published in Nature Geoscience.

Julian Sachs of the University of Washington and colleagues analysed rainfall records in lake and lagoon sediments from four Pacific islands at or near the equator. They discovered evidence to suggest that during the Little Ice Age, many of the islands were considerably more arid than they are today, suggesting that the so-called intertropical convergence zone had shifted southward during that time. They then calculated that the rain band has been migrating north for more than 300 years at a rate of around 1.4 kilometres per year.

If the band continues to move at that rate, a number of islands will soon see dramatic reductions in rainfall. ‘Many people depend on the [rain band] as the source of their fresh water because there is no groundwater to speak of where they live,’ Sachs said. However, the researchers suggest that global warming could accelerate the pace of change, bringing regular drought conditions to equatorial regions.

Rebecca Yap

September 09