Water Scarcity: The Cave’s Freshwater for Life Article Not many people realize that human life has been sustained by only 0.5% of freshwater on Earth. A very small part of this freshwater is hidden – unseen water that is stored deep under the earth in limestone, or karst aquifers. These water sources are now at serious risk due to mining activities, and local communities are trying to find creative ways to access and maintain their freshwater supply. By A.B. Rodhial Falah