Island habitats, home to about 20 percent of the world's biodiversity, are under threat of total submersion with climate change, French researchers warn.

Researchers at the University of Paris Sud have modeled future scenarios to bring attention to the risks that lie ahead for some of the richest biodiversity hot spots worldwide, reporting their results in the journal Nature Conservation.

No global assessment of the consequences of sea level rises is available for island ecosystems, yet those are amongst the regions most vulnerable to potential increases and direct reductions of habitat, they said.

Several recent studies strongly suggest sea levels will rise substantially until the end of the century, with a worst-case scenario of ice sheet melting creating sea-level rises of a worrying 12 feet to 20 feet.

Such increases could lead to the total immersion of very large proportions of many islands with low elevation, wiping out completely self-contained ecosystems and their inhabitants, the researchers said.

Even an increase in sea levels of just three feet would see around roughly 10,800 islands entirely lost, they said.

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