Freshwater contains a low concentration of dissolved salts, making it suitable for most terrestrial life. This resource is fundamental to human civilization, supporting agriculture, industry, and direct consumption. Although the planet is covered by large bodies of water, the vast majority is saline. Understanding where usable freshwater is stored is paramount, as its total volume is small and its global distribution is highly uneven.
Global Freshwater Context
Freshwater makes up only about 2.5% of all the water on Earth. The majority of this volume is not in a readily usable liquid state on the surface. Approximately 68.7% of all freshwater is locked away in the form of ice caps, glaciers, and permanent snow. This cryospheric storage represents the largest pool of non-saline water globally.
The next largest store is subsurface groundwater, accounting for roughly 30.1% of the total, often saturating deep aquifers. Surface water, including lakes and rivers, makes up only a tiny fraction, about 1.2% of all freshwater.
The Continent with the Largest Reservoir
When considering total volume, the continent that contains the most freshwater is Antarctica. This continent holds approximately 70% of the world’s freshwater supply, almost entirely contained within the Antarctic Ice Sheet. The ice sheet blankets nearly 98% of the landmass and averages at least 1.6 kilometers in thickness. If this colossal frozen reservoir were to completely melt, global sea levels would rise by about 60 meters. This represents the largest single store of water on the planet.
Comparing Major Continental Reserves
While Antarctica holds the largest store of frozen water, other continents lead in terms of liquid or renewable freshwater resources. South America, for example, has the largest share of the world’s renewable freshwater. This is primarily due to the colossal drainage basin of the Amazon River, which accounts for a significant portion of the world’s annual river discharge.
Asia also contains a large volume of liquid freshwater, mostly concentrated in Lake Baikal in Russia. Lake Baikal, the deepest and oldest lake in the world, holds roughly 20% of the planet’s unfrozen surface freshwater. North America’s Great Lakes system represents another massive surface water reserve. These continental reserves rely on systems of flow, such as massive rivers or large liquid lakes, which offer a sharp contrast to Antarctica’s static, frozen mass.
Accessibility and Practical Use
The presence of vast water stores in Antarctica does not translate into a usable resource for human populations. The overwhelming majority of the continent’s water is locked in ice far from any major population centers, making it currently inaccessible for consumption or irrigation. Similarly, a significant portion of the world’s groundwater is stored in deep aquifers, which are difficult and costly to tap.
The water that is readily available for human use, which includes lakes, rivers, and shallow groundwater, constitutes a very small percentage of the global total. This readily accessible surface water sustains global agriculture, industry, and municipal supply. Therefore, a continent’s total water volume is a poor indicator of its importance for human consumption, which depends instead on the size and renewability of its liquid surface and shallow subsurface reserves.