permafrost

Canada and Russia, where large amounts of ice and permafrost are melting, are losing the most fresh water.

"The thawing of permafrost at very high elevation led to the collapse of the summit," he explains.

Climate change is causing the glaciers - frozen rivers of ice - to melt faster and faster, and the permafrost, often described as the glue that holds the high mountains together, is also thawing.

Should global warming cause the thick Arctic permafrost to thaw, the vault is still robust enough to preserve its contents he says.

There are still the thawing permafrost and melting ice sheets to take into account.