Most fresh water is ice
About two thirds of the fresh water on Earth is locked in ice sheets and glaciers, and almost all of that ice is in Antarctica.
Established2 min read
The ocean is about 97 percent of all water, and it is salty. Of what is left, inventories going back to Shiklomanov put roughly two thirds in the great ice and only a few tenths of a percent in lakes and rivers. Groundwater is the other large term.
Antarctica holds on the order of 90 percent of the ice. Greenland holds most of the rest. If either sheet returned fully to the ocean, sea level would rise by tens of metres. That is an accounting identity, not a forecast of when.
Caveats
- The fractions depend on what is counted as fresh. Some deep groundwater is brackish and is left out.
- Ice volume estimates improve as the sheets are surveyed. The 'about two thirds' is stable against those revisions.
Sources
- 1Shiklomanov I. A.. World fresh water resources. Water in Crisis (Gleick, ed.), 1993.