Freshwater, defined as naturally occurring water with low concentrations of dissolved salts, represents a small fraction of the planet’s total water supply. Approximately 97 percent of all water on Earth is saline, leaving less than three percent as freshwater. This limited resource is not distributed equally across the globe, leading to significant regional variations in water security and availability.
Understanding Global Freshwater Storage Types
Before examining continental stores, it is helpful to understand the various forms freshwater takes and their relative sizes. The overwhelming majority of the world’s freshwater is not in a liquid state readily available in rivers or lakes. Instead, it exists in three primary storage forms: ice, groundwater, and surface water.
Ice caps and glaciers hold the largest share, accounting for just over two-thirds, or roughly 68 percent, of all freshwater on the planet. This frozen mass is concentrated in the polar regions and high mountainous areas. The second largest reservoir is groundwater, which makes up approximately 30 percent of the total freshwater supply.
This groundwater is stored in aquifers and rock layers beneath the Earth’s surface. Surface water, which includes the rivers, lakes, swamps, and atmospheric water vapor that people most frequently see and use, constitutes the smallest portion. Lakes and rivers combined account for less than one percent of the world’s total freshwater.
The Continent Holding the Greatest Total Volume
The continent that holds the greatest total volume of freshwater is Antarctica, which is entirely covered by a massive, permanent ice sheet. This ice mass contains approximately 70 percent of the world’s freshwater supply. The volume of ice is estimated to be over 27.6 million cubic kilometers.
This immense reserve is almost entirely frozen and therefore inaccessible for practical human consumption. The Antarctic ice sheet covers nearly 14 million square kilometers, an area almost twice the size of Australia. This accumulation of ice has been building for millions of years, reaching depths of up to 4,500 meters in some places.
If the entire Antarctic ice sheet were to melt, global sea levels would rise by an estimated 60 to 70 meters. This single continent’s frozen store dwarfs the combined freshwater resources of all other continents.
Continental Distribution of Liquid Freshwater
While Antarctica dominates the total volume, a different picture emerges when focusing on the distribution of liquid, usable freshwater. This distinction between frozen storage and accessible reserves highlights the continents with the largest liquid surface and groundwater resources. Liquid freshwater is primarily found in the large river basins, major lake systems, and extensive underground aquifers of the other continents.
South America possesses significant liquid water resources, largely due to the Amazon River Basin. The Amazon’s immense flow accounts for a substantial portion of the world’s total river discharge. This extensive system, combined with deep groundwater reserves, makes the continent a major holder of renewable liquid freshwater.
Asia also contains massive reserves, notably in the form of Lake Baikal in Russia. Lake Baikal alone holds about 20 percent of the world’s total unfrozen surface freshwater. Furthermore, the continent’s vast landmass contains some of the largest and deepest aquifer systems, though demand from its large population places heavy pressure on these resources.
North America is another continent with a significant store of liquid water, predominantly in its surface water bodies. The Great Lakes system, shared by the United States and Canada, holds a sizeable fraction of the world’s surface freshwater. This reserve, along with other major river systems, provides a relatively stable supply of readily accessible water across the continent.