Why Is the Water Cycle Important to Life on Earth?

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The water cycle is responsible for distributing water across the earth through evaporation, condensation and precipitation, a process that is vital for sustaining life on earth by providing water to plants, animals and humans. It is also the driving force behind the earth's climate. Clouds are formed through condensation, and temperature is regulated through evaporation and water vapor in the air.

Water is continuously being re-circulated in a process that consists of three major steps. The first step is evaporation. Approximately 85 percent of the water vapor in the air is from the oceans, while the rest comes from the land and fresh water sources.

Next, the water vapor condenses into droplets. At ground level, this condensation accumulates on plants and soil as dew or frost, but higher in the atmosphere it forms clouds. Depending on the atmospheric conditions, clouds either disperse back into vapor or continue to condense until they must precipitate, which is the third step.

Precipitation happens as either rain or snow. As it hits the ground, some of it soaks into the soil to be stored in underground reservoirs, some is used by plants and animals and some rejoins the lakes, rivers and oceans. Then the water cycle begins again.