There are approximately 1,4 billion km3 of water on earth. It is found in different environments and in three distinct phases.
Next time you drink a glass of ice water, consider that you are experiencing water in all three its phases. The solid ice cools the liquid in your glass, and the air you breathe is full of water vapour. This is possible because it can naturally exist in all three its phases in the temperature and pressure ranges that are common on earth.
Ice in the polar regions freezes and thaws with the seasons and plays a crucial role in regulating the earth’s climate. Water also has a remarkable ability to absorb and retain heat. The sun delivers a tremendous amount of energy to the earth every day and the tropical oceans absorb much of that energy. In addition, a lot of it goes to creating water vapour, which is the source of all rain and snow. The 13 trillion tons of water in the atmosphere is responsible for absorbing approximately 70% of all atmospheric radiation from the sun.
Water in different environments
Phase change depends on temperature and pressure. During each phase change a specific amount of latent heat is either absorbed or released without the sensible temperature changing. These different processes contribute to cooling and warming the air in the troposphere (Figure 1).
The oceans contain approximately 97,25% of the total volume of water on earth and cover 70,8% of the planet’s surface. The water in the oceans plays a key role in regulating temperatures across the globe.
Water on land consists of the following:
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