Estimates of groundwater are particularly difficult to make, and they vary widely. Freshwater exists in lakes, rivers, groundwater, and frozen as snow and ice. Only a thousandth of 1% of the water on Earth exists as water vapor in the atmosphere.įor human needs, the amount of freshwater on Earth-for drinking and agriculture-is particularly important. As for the rest, approximately 1.7% is stored in the polar icecaps, glaciers, and permanent snow, and another 1.7% is stored in groundwater, lakes, rivers, streams, and soil. In all, the Earth’s water content is about 1.39 billion cubic kilometers (331 million cubic miles), with the bulk of it, about 96.5%, being in the global oceans. Sometimes, all three states are even present in the same time and place, such as this wintertime eruption of a geyser in Yellowstone National Park. Water is the only common substance that can exist naturally as a gas, liquid, or solid at the relatively small range of temperatures and pressures found on the Earth’s surface. In particular, water appears to be a necessary ingredient for the development and nourishment of life. Believed to have initially arrived on Earth’s surface through the emissions of ancient volcanoes, water is a vital substance that sets the Earth apart from the rest of the planets in our solar system. ![]() Geologic evidence suggests that large amounts of water have likely flowed on Earth for the past 3.8 billion years-most of its existence. Viewed from space, one of the most striking features of our home planet is the water, in both liquid and frozen forms, that covers approximately 75% of the Earth’s surface. Water is practically everywhere on Earth. There are many ways in which the energy, water, and biogeochemical cycles (cycles of the elements that involve life, chemicals, and the solid Earth) interact and influence the Earth System. This flow of energy from the Sun, through the environment, and back into space is a major connection in the Earth system it defines Earth’s climate. Eventually, the energy that began as Sunshine (short-wave radiation) leaves the planet as Earthshine (light reflected by the Atmosphere and surface back into space) and infrared radiation (heat, also called longwave radiation) emitted by all parts of the planet which reaches the top of the Atmosphere. These motions, such as wind patterns and ocean currents redistribute energy throughout the environment. Differences in the amount of energy absorbed in different places set the Atmosphere and oceans in motion and help determine their overall temperature and chemical structure. ![]() ![]() This energy flows into the Atmosphere and heats this system up It also heats up the Hydrosphere and the land surface of the Geosphere, and fuels many processes in the Biosphere. Energy CycleĮnergy from the Sun is the driver of many Earth System processes. ![]() Diagram showing parts of the Earth system. Image Credit: NASA's Goddard Space Flight Center.Įxplore the energy and matter cycles found within the Earth System.
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