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How Would Changes in Weather Affect the Hydrologic Cycle?

Water on the surface of the planet evaporates into the air, accumulates in the atmosphere to form clouds and returns to the earth in the form of rain, snow or hail. This is the Earth's hydrological cycle. Changes in weather, such as temperature and the intensity and frequency of precipitation, can affect the water cycle.

  1. Intensified Water Cycle

    • As temperatures rise, so do the rates at which water evaporates and snow melts. When this happens, the entire hydrologic cycle speeds up; water is quickly returned to the atmosphere, meaning more frequent and intense periods of precipitation. Glaciers also affect the water cycle. Because glaciers reflect so much sunlight, they create their own weather patterns by warming the air directly above them. These pockets of warm air influence wind patterns; if the glaciers melt, there would be a further disruption in the weather.

    Flooding and Drought

    • If snow melts and evaporates too quickly, surface water will not have enough time to sink into the ground or travel into rivers, and the hydrologic cycle for a given area could be greatly altered. As weather patterns become more erratic, the distribution of the planet's water changes. Regions which used to have regular rainfall begin to experience long periods of drought. Rivers overloaded by a fast spring snow melt or a sudden, large amount of rainfall become swollen and overflow, resulting in a flood.

    Water Levels

    • Erratic and intense weather patterns have a direct effect on the availability of groundwater. When surface water and snow evaporate and melt quickly, it does not have time to percolate down into the aquifer and replenish groundwater. As icebergs melt into the ocean, sea levels rise. When this happens, much of the water cycle takes place on the surface of the earth and in the atmosphere, putting a greater strain on the hydrologic cycle.

    Impact on Human Life

    • If the earth's weather were to become more erratic, it could have implications for humans. A change in the hydrologic cycle could mean that an area which depends strongly on rainfall for agriculture could start to see differences in the duration and intensity of seasons, and farmers would have to plan for flooding or drought. Water quality will also be affected by changing weather patterns. When water levels are low, as in a drought, pollutants become concentrated. During flood conditions, sediments and others pollutants can wash into drinking water sources.

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