Almost three quarters of the Earth surface are covered with water. The vast majority of water is stored in oceans. Freshwater makes up only 2.5 % of total Earth water. By far the largest volume of water is in the Pacific Ocean. The overall proportion of water in rivers in global context is almost negligible (which, however, certainly does not mean that rivers are negligible as such), they account for only approx. 0.00015 % - if all the water in the world were a 150-liter bathtub, there would only be 20 ml in rivers. Most freshwater is stored in glaciers and ice caps, and most surface water is also made up of ice or stored in permanently frozen soil (permafrost).