Overview
About 97.5 percent of the water on earth is salt water; the remaining 2.5 percent is fresh water. About two-thirds of the fresh water is locked up in ice sheets and glaciers. So that leaves only about 1.7 percent of the earth’s water in liquid form. But about 96 percent of that liquid fresh water is underground, so that leaves only about 0.07 percent in lakes, rivers and in the atmosphere in the form of water vapor and rain.
The ground water in aquifers is accessible from wells and springs, but many of those aquifers are not being recharged by surface water, and depletion continues without meaningful controls. When aquifers seize to be the dominant source of fresh water, humans will have to rely more and more on surface water, which currently is only a small fraction of the world’s supply of liquid fresh water. Conservation measures and alternative sources such as desalination are successfully being applied.
Some scientists consider the availability of fresh water resources to potentially be a greater global problem than that of climate change.
Wikipedia Water Resources
USGS Water Resources
GreenFacts
Supporting Viewpoints
Conservation measures and improved efficiency of water usage has the most potential for extending existing supplies of fresh water. Recycling of water on golf courses, capturing of rain water in holding ponds, injecting river water into shallow aquifers during winter periods of low usage, and xeriscaping homes outdoors are some of the conservation methods being applied.
In the Middle East and other parts of the world, desalination plants extract potable water from seawater where energy supplies are abundant. There are 13,080 desalination plants in operation worldwide. In Japan, India and Russia, nuclear reactors coupled to desalination plants are being used as a source of large quantities of potable water.
The city of Las Vegas has floated the idea of building desalination plants in California or Mexico in exchange for a greater share of the Colorado River water.
Supporting Websites
WaterandWastewater.com
Carlsbad Desalination Project
Clear Water Solutions
Opposing Viewpoints
Americans generally recognize that the world’s supply of fresh water resources are diminishing and have been supportive of conservation measures that support the common good. However, they have not made the leap to desalination plants because of both the high energy costs associated with extracting potable water using desalination technology, and also the resultant negative environmental impact if fossil fuels are used as a source of that energy.
In addition in some places like California, there is opposition to desalination plants because of the potential effect on the salinity of coastal waters as the salty brines extracted from the process are returned to the ocean.
Opposing Websites
Environmental Science and Technology
World Wildlife Fund
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