Most of Earth's freshwater (about 68.7%) is locked up in ice caps and glaciers. One concern about global warming is that it will melt the ice caps and cause the oceans around the world to rise, wreaking havoc on inhabitants of coastal regions.
Seventy-one percent of Earth's surface is covered by water. The oceans hold about 96.5% of this total value of water. Water also exists in the atmosphere as water vapor, in freshwater sources (rivers, streams, ponds, lakes, creeks, etc.), in icecaps, and in glaciers. Freshwater accounts for only 2.5% of all water on Earth, yet it is the only form that living things use for drinking. This is why it is so important not to contaminate our water sources with pollutants such as fertilizers, fuels, or pesticides.