Global warming may wipe out three-quarters of Europe's alpine glaciers by 2100 and raise sea levels by four metres by the year 3000 through melting the West Antarctic ice sheet, two studies say.

The research places the spotlight on some of the least understood aspects of climate change: how, when and where warming will affect glaciers on which many millions depend for their water, and the problems faced by generations in the far distant future.

Pieces of ice fall from the Perito Moreno glacier near the city of El Calafate, in the Patagonian province of Santa Cruz. Credit:Reuters

The glacier study, published on Sunday, predicts mountain glaciers and icecaps will shrink by 15-27 per cent in volume terms on average by 2100.

"Ice loss on such a scale may have substantial impacts on regional hydrology and water availability," it warns.