Greenland's icesheet is being significantly eroded by winds and currents that drive warmer water into fiords, where it carves out the base of coastal glaciers, new studies say.

The icy mass sitting atop Greenland holds enough water to boost global sea levels by seven metres, potentially drowning low-lying coastal cities and deltas around the world.

At present, the ocean watermark is rising at about 3 millimetres per year, a figure that compares with 1.8 millimetres annually in the early 1960s.

But Greenland's contribution has more than doubled in the past decade, and scientists suspect climate change is largely to blame, although exactly how this is occurring is fiercely debated.

Some theories point to air temperatures, which are rising faster in far northern latitudes than the global average.

A rival idea is that shifting currents and subtropical ocean waters moving north are eroding the foundation of coastal glaciers, accelerating their slide into the sea, especially those inside Greenland's many fiords.

Agence France-Presse