Island Diversity in Danger of Total Submersion from Sea Level Rise

Sea level rise is a huge issue for low-lying island habitats. As the climate continues to change, though, nearly 20 percent of the world's biodiversity is in danger. Now, scientists have taken a closer look at rising sea levels, revealing the potential for a catastrophic future.

Climate change has received quite a bit of attention in recent years, but there has been no global assessment of the consequences of rising sea levels for island ecosystems. These regions, though, are the most vulnerable to potential sea level rise, which would result in a direct reduction of habitat.

In fact, recent studies have shown that sea levels will rise substantially until the end of the century, with estimates ranging from .5 m to 2.3 m increase. Worst case scenarios that involve ice sheet melting and sliding have led to estimates of massive 4 to 6 m increases. These increases could lead to the immersion of very large proportions of many islands with low elevation. In fact, in some cases this rise could lead to total submersion and wipe out completely self-contained ecosystems and their inhabitants.

In order to assess the impacts of sea level rise on islands, the scientists examined the 1,269 islands from different areas that France harbored. The French maritime domain is ranked as the second most important in the world; these islands in total hold a large proportion of the world's biodiversity.

So what did the researchers discover? It turns out that 5 percent of the number of islands could be permanent inundated under an increase of sea level by 1 meter. This figure rises to 8 percent and 11 percent under more pessimistic scenarios, such as 2 and 3 meters of sea level rise. In fact, roughly 10,800 islands could potentially be lost under the most optimistic scenario.

"Losses of insular habitats will thus be relatively important in the future, probably lead to a major impoverishment of insular biodiversity," said C. Bellard, one of the researchers, in a news release. "Given the implications of these results, decision makers are required to define island conservation priorities that accounts for sea level rise following climate change."

The findings are published in the journal Nature Conservation.