The global hydrological cycle in the atmosphere and ocean plays an important role in determination of the climatic state of the Earth. The atmosphere transfers to the continents about 40 th km3 of fresh water per year. Directly above the continents, this volume is supplemented with an additional amount of water due to evaporation and transpiration of vegetation. After precipitation above the continents occurs, the balanced reverting flow from them into the ocean will apparently make 40 th km3, largely composed of river run-off and a considerably lesser amount of ground water. The ocean transfers water by means of the "conveyor belt" mechanism from high and moderate latitudes to tropical zones, where they enter the atmosphere because of evaporation. The atmospheric processes transfer this water to moderate and high latitudes where it falls as precipitation onto oceans and continents, then the cycle repeats.