Description
For millions of people, glaciers are a major source of fresh water, collecting it in the winter and then releasing it in the hotter dry season.
They keep rivers flowing, farmers farming and cities supplied with drinking water. This is much more than an environmental disaster.
We went to the Andes in South America to film the testing of glaciers there, to find out whether they are supplying as much water as they used to. We found some surprising results.