If sea levels continue to rise as many climate scientists have predicted, island sanctuaries in the Pacific, including those in New Zealand could be submerged in water. According to a new study, the world's rarest animals could disappear along with the islands.

Researchers in the University of Auckland said conservation projects on islands free from pests could be undone since many of the low-lying islands may be underwater when sea level rises by up to 2.3 metres by 2100.

The new study was published in the international journal Trends in Ecology and Evolution. It revealed how 20,000 islands around the world could be swallowed by the ocean, threatening hundreds of species on the brink of extinction.

Out of 604 island sanctuaries, 26 are predicted to be completely submerged when sea levels rise. Dr James Russell, co-author of the study from the University of Auckland's School of Biological Sciences, said New Zealand is the world leader in eradicating pests and translocations for decades. Dr Russell added that the climate change will push New Zealand to focus on conservation projects in bigger islands like the Aotea or Great Barrier Island, Stewart Island and the New Zealand mainland.

Aside from rising sea levels, rare animal species will also face frequent cyclones with greater intensity, including bigger waves. Seawater flooding is predicted to also increase which may lead to loss of habitat.

Unlike the animals with the mainland as their natural habitat, island species have nowhere else to go. Mr Russell said the world may soon face the decision of relocating island animals to save the species. He has worked with other researchers from Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the University of Paris Sud.

The threat of rising sea levels is blamed on climate change and global warming. Scientists have observed that the Arctic is no longer as white and bright like before since more ice has melted into the ocean. The study revealed less of the sun's heat will reflect into space because of the Arctic's dark and open water in the summer.

According to the latest study published in the National Academy of Sciences, the Earth may be absorbing more heat than expected which contributes to global warming.