The world is made up of 70% water, but only a measly 2.5% of that water is fresh. What’s even worse is that only 0.007% of that water is easily accessible to people. About 97% of the earth’s water is salt water, and while marine plants and animals have physically adapted to its high sodium content, seawater remains unsuitable for human consumption.
Salt water is unsuitable for drinking not only because it tastes bad, but also because it could cause a lot of damage to a person’s health. Sicknesses associated with drinking too much salt water are high blood pressure, nausea, brain damage and many others.
Ironically, instead of quenching a person’s thirst, seawater makes you even thirstier. The salinity in seawater is so much higher than what our bodies can usually take. Kidneys help get rid of excess salt by producing urine, but since freshwater is necessary to dilute the salt, ingesting a high amount of salt water without drinking freshwater may cause dehydration, and eventually lead to death.
Technological advancements, however, have made it possible to make salt water appropriate for consumption. A reverse osmosis water filter system, for example, can make salt water drinkable and safer to use.