Earth's Clean Water Supply


To understand what is happening to the current supply of clean water on earth.

Early Findings


  • The amount of clean water on earth "has remained fairly constant over time—continually recycled through the atmosphere and back into our cups".
  • Despite the fact that over 70 percent of the earth's surface is covered in water, only 2.5 percent of that number is "fresh" water, with the rest being saline- and ocean-based.
  • Further, an additional 1.5 percent of that water is inaccessible, meaning that only one person of the earth's total water sources are accessible, fresh water.
  • While water scarcity is a continuing and growing problem throughout the world, non-profit groups and charities have been working to combat its effects. "Through their efforts, the number of people drinking from ponds, rivers, swamps, and contaminated springs has fallen from approximately 16.5 percent of the global population to just 8 percent [1], impacting almost 500 million people."

    • The primary causes of water scarcity are population growth, urbanization, competition, climate, and war. Ultimately, water scarcity throughout the world is a result of a combination of these factors.
    • In addition to these causes, water scarcity is also partly due to inefficient use of water resources. Specifically, "water use has grown at more than twice the rate of population increase in the last century". This means that humans are using more water than we need, contributing to water scarcity for parts of the population.
    • While the amount of fresh water on earth has remained constant over time, the population has grown exponentially, resulting in the need for more clean water than has been necessary in the past.
    • In addition, climate change has also contributed significantly to water scarcity. Specifically, "climate change has disrupted the Earth’s hydrological cycle (water cycle), changing when, where, and how much precipitation falls. That has made water management planning far more challenging".


    • Currently, 844 million people are living without access to clean water.
    • This number is expected to grow to about 1.8 billion people by 2025, accounting for roughly half of the global population.
    • In areas experiencing water scarcity, the rates of disease and poverty are higher as well.
    • "Together, unsafe water and the inaccessibility of basic sanitation are leading contributors to extreme poverty."
    • Even for those who do have access to safe, clean water, there are barriers to accessing it. Specifically, "262 million [people] are drinking what’s classified as safe water, but they are traveling over 30 minutes to fetch it".

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