The total volume of water on Earth is about 1,400,000,000 cubic kilometers. Only 2.5% of that is fresh water. 70% of that fresh water is locked in the ice caps and glaciers. Nearly 30% of it is groundwater. Only about 0.3% of our fresh water is avaiable for use in lakes, streams, rivers, etc. So.... availability of fresh water will be a very serious, life or death, peace vs war, type of problem for everyone in the very near future.