While many scientists think warming air from climate change may speed the melting of polar ice glaciers, one group of researchers is keeping an eye on warming oceans beneath the glaciers.

Experts from the University of Arizona say warm water under the ice in Greenland and Antarctica could mean polar ice will melt faster than expected.

Lead researcher Jianjun Yin notes that an ice cube in a warm room takes several hours to melt, while a cube dropped in warm water will disappear in just minutes.

Yin and his team say the ocean near Greenland could warm as much as two degrees Celsius by the year 2100. Their study appears in the latest issue of the journal Nature Geoscience.

Some island nations are urging wealthier countries to do more to fight climate change, saying rising sea levels could wipe them out.