Extensive land irrigation can, indeed, affect the weather. As of 2000, the total amount of land on Earth that has been irrigated is about 689 million acres. About 60 percent of the world’s fresh water supplies are used toward this purpose, representing 137 billion gallons (518.5 billion liters) of water daily. As one might imagine, when all of this water is spread over cropland, a certain amount of it will evaporate into the atmosphere. Hydrologists believe that this amount of evaporation is enough to increase the number of rainstorms that would otherwise occur.