Question

How does the amount of freshwater in glaciers and ice caps compare to the amount of freshwater in sources that can be easily accessed and used? How does the amount of freshwater compare in general with the total amount of Earth’s water supply? (Site 1)

Answer 1

Short answer
- Most of Earth’s water is saltwater in the oceans (~97.5%). Freshwater is only about 2.5% of the total. (Source: USGS.)
- Of that small fresh‑water portion, about 68–69% is frozen in glaciers and ice caps. Groundwater holds about 30% and all surface fresh water (lakes, rivers, swamps, soil moisture, atmosphere) is only a few tenths of a percent of the freshwater supply.
- That means the easily accessed freshwater (rivers and lakes in particular) is a vanishingly small fraction of Earth’s total water — only a few hundredths of a percent of all water on Earth.

Numbers from the USGS (rounded)
- Total water on Earth ≈ 1.386 billion km³.
- Freshwater ≈ 35 million km³ (≈ 2.5% of total).
- Glaciers & ice caps ≈ 24 million km³ (≈ 68.7% of freshwater).
- Groundwater ≈ 10.5 million km³ (≈ 30.1% of freshwater).
- Surface water & other accessible freshwater (lakes, rivers, soil moisture, swamps, atmosphere) ≈ 140,000 km³ (≈ 0.4% of freshwater); rivers alone are only about 2,000 km³.

Implication
- Although most of Earth’s freshwater is in glaciers and ice caps, that water is not directly usable for most human needs without ice‑melting and transport. The relatively tiny amount in rivers and lakes (and the portion of groundwater that is renewable and reachable) is what people and ecosystems mainly rely on, which helps explain why water scarcity occurs even on a planet that appears “water rich.”

If you want, I can give the exact USGS source link or make a small chart comparing these percentages.