Earth is made up of 70 per cent water, yet countries worldwide run the risk of water shortage as pressure increases on natural resources. This 71% includes both saltwater bodies like oceans and freshwater sources such as rivers, lakes, and glaciers. Scientists have now estimated how much water runs through Earth’s rivers, the rates at which it flows into the ocean, and how much both of those figures have fluctuated over time. The analysis has revealed regions depleted by heavy water use, including the Colorado River basin in the United