According to the National Aeronautics and Space Administration’s Goddard Institute for Space Studies, humans alter the planet’s water cycle by changing stream flow patterns. These changes cause the alteration of the sea level and ocean salinity, as well as altering the land’s physical properties. Left unchecked, such disruptions could play a part in changing the planet’s climate.
Humans are reducing the amount of runoff water that reaches the world’s oceans. By changing the flow of rivers and removing vegetation from the land, humans have removed about one percent of the total yearly stream flow, which represents about 10 percent of the freshwater used by people in a single year.
These changes have already caused drastic results in some areas. For example, the Aral Sea’s water level has dropped by about 45 feet since the 1960s. Additionally, the coastline of Louisiana has experienced extreme amounts of erosion due to the human manipulation of the water cycle.
Interestingly, some of these changes are offsetting the rise in global sea level that is occurring due to anthropogenic climate change. Were it not for the reduction in sea level caused by human water use, the global sea level would be rising faster than it is.