In this never-ending cycle, the oceans on the Earth play a very important role in stabilizing the climate because they accumulate and give up enormous quantities of heat much more slowly than the atmosphere above it. The oceans cover approximately 70% of the Earth's surface and occupy a volume of 1 400 000 000 cubic kilometers. Their average level tends to remain constant, at least from year to year; however the variations in the quantities of water trapped in glaciers may produce small changes in the level from one century to another. In the past, during those periods of intense cold known as the glacial eras, a huge amount of water was present in the polar caps and over the continental masses in the form of ice, and the sea level was about one hundred meters lower than it is today. If on the other hand, for the sake of argument, all the ice on the Earth would melt and release its water into the oceans, the average level of the oceans would rise by 70 meters. That doesn't seem to be very much, but it would be enough to submerge all the ports that we know along with vast coastal areas. But the oceans are also affected by other variations in level: the tides, which depend on the gravitational attraction of the Moon and the Sun. The most intense tides occur when the Sun, the Moon and the Earth are all aligned; the smallest tides occur when the Sun, the Moon and the Earth form a right angle. The water in the oceans has a stratified structure, similar to the atmosphere, and, like in the atmosphere, variations in temperature and chemical composition produce those great movements of water called currents. Similar to huge rivers flowing on the surface, currents make it possible to exchange nutritional substances, which are fundamental for life in the oceans, and also to influence the climate on the continents that they contact. The most famous one is the Gulf Stream, one hundred billion tons of warm water that every hour move between Florida and the island of Cuba to reach the northern Atlantic, and from here the shores of western Europe, Great Britain and Iceland: if it weren't for this extraordinary oceanic river, the Atlantic coasts would be covered with ice and Europe as we know it today would never have existed, but instead would be similar to Alaska. However, there are also cold currents in the ocean, such as the Labrador Current, which from the Arctic Ocean moves to the shores of Greenland, or the icy antarctic currents that transport the polar water to the equator. However, this continuous mixing of the oceans only involves the surface layers. In general, salt water, which in addition to salts and organic substances also contains various types of dissolved gases such as oxygen, nitrogen and carbon dioxide, has a temperature that, except in the polar areas, tends to decrease with depth only up to 1 000 - 1 500 meters, after which it remains constant between 4 and 5 degrees.
In this never-ending cycle, the oceans on the Earth play a very important role in stabilizing the climate because they accumulate and give up enormous quantities of heat much more slowly than the atmosphere above it. The oceans cover approximately 70% of the Earth's surface and occupy a volume of 1 400 000 000 cubic kilometers. Their average level tends to remain constant, at least from year to year; however the variations in the quantities of water trapped in glaciers may produce small changes in the level from one century to another. In the past, during those periods of intense cold known as the glacial eras, a huge amount of water was present in the polar caps and over the continental masses in the form of ice, and the sea level was about one hundred meters lower than it is today. If on the other hand, for the sake of argument, all the ice on the Earth would melt and release its water into the oceans, the average level of the oceans would rise by 70 meters. That doesn't seem to be very much, but it would be enough to submerge all the ports that we know along with vast coastal areas. But the oceans are also affected by other variations in level: the tides, which depend on the gravitational attraction of the Moon and the Sun. The most intense tides occur when the Sun, the Moon and the Earth are all aligned; the smallest tides occur when the Sun, the Moon and the Earth form a right angle. The water in the oceans has a stratified structure, similar to the atmosphere, and, like in the atmosphere, variations in temperature and chemical composition produce those great movements of water called currents. Similar to huge rivers flowing on the surface, currents make it possible to exchange nutritional substances, which are fundamental for life in the oceans, and also to influence the climate on the continents that they contact. The most famous one is the Gulf Stream, one hundred billion tons of warm water that every hour move between Florida and the island of Cuba to reach the northern Atlantic, and from here the shores of western Europe, Great Britain and Iceland: if it weren't for this extraordinary oceanic river, the Atlantic coasts would be covered with ice and Europe as we know it today would never have existed, but instead would be similar to Alaska. However, there are also cold currents in the ocean, such as the Labrador Current, which from the Arctic Ocean moves to the shores of Greenland, or the icy antarctic currents that transport the polar water to the equator. However, this continuous mixing of the oceans only involves the surface layers. In general, salt water, which in addition to salts and organic substances also contains various types of dissolved gases such as oxygen, nitrogen and carbon dioxide, has a temperature that, except in the polar areas, tends to decrease with depth only up to 1 000 - 1 500 meters, after which it remains constant between 4 and 5 degrees.
