A New Zealand researcher says Pacific Islands still face serious threats from rising sea levels even though his research suggests most are not shrinking.
A study of 27 Pacific Islands has found 45 percent have maintained a stable surface area in the last 60 years, while 45 percent have grown.
Researchers, including Paul Kench from the University of Auckland, used historical aerial photos and high resolution satellite images to find just four islands had diminished in size since the 1950s.
He says rather than sinking as sea levels rise, some islands are growing or moving on their reef platform as waves move debris from the coral reefs around them.
He says more needs to be learnt about waves and whether coral reefs will continue to produce enough sand.
"There's at one level cause for optimism because I firmly believe that most of these nations will have land resources at their disposal in the next century, but at the next level I think what it actually places in front of these countries are very real and significant environmental threats."
Paul Kench says research is needed to find out which islands will remain habitable.
