See How They Grow

One of the most dire climate-change scenarios is that small island nations, such as the Maldives, could literally go under as sea levels creep upward. But the situation may not be as bad as people have feared, scientists say. In fact, an analysis has shown that many reef islands have actually been getting bigger in recent years.

Researchers studied aerial photographs and satellite images of 27 Pacific atoll islands, with datasets spanning 19 to 61 years. Forty-three percent of the islands stayed approximately the same size, and 43 percent grew larger. Meanwhile, a mere 14 percent got smaller, even though sea levels have been rising by 2 millimeters per year in that region.

How is this possible? Some of the islands’ shorelines did experience erosion, as one might expect. But sea level wasn’t the only factor affecting the land. For example, sediment may have accumulated on other parts of the islands as well, the authors say in a manuscript accepted for publication in Global and Planetary Change. So island nations will have to consider which types of changes are most likely to occur over the coming years. – Roberta Kwok

Source: Webb, A.P. & P.S. Kench. 2010. The dynamic response of reef islands to sea level rise: evidence from multi-decadal analysis of island change in the central Pacific. Global and Planetary Change DOI:10.1016/j.gloplacha.2010.05.003.

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