3: Global Water Resources and Use
WATER DISTRIBUTION AND PROPERTIES
Over 70% of Earth’s surface is covered by water. Oceans hold about 97% of all
water on Earth, while freshwater constitutes about 3%. Of the freshwater that is
available, most of it is trapped in glaciers and ice caps. The rest is found (in
descending order) in groundwater, lakes, soil moisture, atmospheric moisture,
rivers, and streams.
Figure 3.1 Distribution of Earth’s waterWater has many unique properties:
■ Strong hydrogen bonds hold water molecules to each other.
■ The temperature of water changes slowly due to its high specific heat
capacity.
■ Water has a high boiling point.