The world’s floating ice is in “constant retreat”, showing an instability which will increase global sea levels, according to a report published in Geophysical Research Letters in April 2010.

Floating ice has disappeared at a steady rate over the past 10 years, according to the first measurement of its kind. That is greater than the loss of ice over land from the Greeanland and Antarctic ice sheets over the same time period, highlighting the impact of warming oceans on floating ice.

The study did not shed new light on how soon the North Pole may be ice-free in summer, which many climate experts say could happen by 2050, perhaps even earlier.

If all the world’s floating ice melted it would add about 4 centimeters to sea levels. But this could have a bigger effect by unblocking glaciers over land, which could slide faster into the sea, and also because open water reflects less sunlight than ice, warming the local sea.

If all the world’s polar ice melted it would raise sea levels by about 70 meters, scientists estimate.

Posted: April 2010; Source: Planet Ark