Millions of people in South America and Asia face chronic water shortages within decades as the world’s glaciers and ice caps are now in terminal decline because of climate change. A survey has revealed that the rate of melting across the world has sharply accelerated in recent years, placing even previously stable glaciers in jeopardy.

Georg Kaser, a glaciologist at the University of Innsbruck, Austria, who led the latest alarming scientific research, said that “99.99% of all glaciers” were now shrinking. “The glaciers are going to melt and melt until they are all gone. There are not any glaciers getting bigger any more”.

Shrinking glaciers in South America would deny major cities water supplies and put populations and food supplies at risk in Colombia, Peru, Chile, Venezuela, Ecuador, Argentina and Bolivia. Other countries are noticing effects too. Snow and ice cover in the eastern Himalayas has shrunk by about 30% since the 1970s.

So what are people going to drink when the water runs dry?