How much water in the earth’s surface is drinkable?
Well, you will be shocked if I tell you only 0.0076% of the water on the earth surface is available to drink. But, that’s the truth. As we know 71% of our earth is covered by water and 29% of the rest is land. 97.5% of earth’s water is SALT water which we can’t drink. Out of 2.5% of fresh water, only 0.3% of the available water is potential to drink.
Existence of fresh water can be found in air as water vapor, in lakes and rivers, on Mount Everest as icecaps and as glaciers in Antarctica or Alaska. All those water resources do not have the potential to reach us but because water never sits still and thanks to the water cycle, water is constantly active and moving from one place to another, forming as evaporation, condensation and rain. When it rains, water is absorbed into the ground and feeds aquifers, which are like large underground areas that store water. Rain water also seeps into the upper layers of the ground and is called ground water, which keeps our waterways flowing.
The Earth’s surface actually has more freshwater stored in the ground than there is on the surface. In the United States in 2010, we used about 275 billion gallons of surface water per day and about 79.3 billion gallons of groundwater per day. Although we used surface water to supply drinking water and to irrigate crops, groundwater is not only important to keep rivers and lakes full, it also provides water for people where visible water is scarce such as in desert towns of western region of United States like Arizona, Nevada or California.
Nature.com talks about how “ground water plays a central part in sustaining ecosystems and enabling human adaptation to climate variability and change.” The article points out that as climate change progresses the climate extremes such as droughts and floods will increase, impacting the amount of rain fall, which in turn will affect the groundwater and surface water. This will ripple out and ultimately impact global water ways and food security.
