What do you know about the amount of water on Earth? Learn the information below.
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Looking at our planet from space, she seems blue. This is due to the fact that water covers more than 70% of the earth's surface in the form of seas, rivers, lakes, oceans and glaciers.
What is a hydrosphere and what does it consist of?
Suffice it to say that the Pacific Ocean, which is the largest, has a large surface than the entire surface of the land of the Earth. However, data related to the volume of the Earth show that the hydrosphere is only an eight hundred of it: a very modest part. Most of the planet consists of rocky materials.
Why, then, if we look at the ground from space, does it seem light blue? Because water is collected on the surface.
- Hydrosphere It is a set of water present on our planet in any form (liquid, gaseous, solid, etc.). Therefore, not only oceans, seas, lakes and rivers, but also glaciers and water vapor, even if they represent a small part of the total amount of water on our planet, fall into the hydrosphere.
- Naturally, we are not talking about drinking water, but about all the reserves of the water present on Earth, and in any form. In this sense, it can be argued that the hydrosphere is an almost inexhaustible source. A separate discussion should be made in relation to drinking water. There are still people who die because they do not have sufficient reserves of drinking water, and therefore we must protect this precious resource as much as possible.
Most of the water present on Earth falls into the hollows, which are naturally found on the lithosphere on the hardest part of the planet. These cavities provoke the origin of lakes and rivers.
The presence of water on Earth is a prerequisite for the development and maintenance of life, as we know it. The volume of water on Earth is estimated at 1,400,000,000 km³. Approximately 71% of the surface of the planet is covered with water. This is a very small part from the entire volume of the Earth and is estimated at 1.08321 × 10¹² km ³:
- 96.5% of the total in oceans and seas
- about 2% in glaciers and polar ice
- about 2% in soil and groundwater
- about 0.02% fresh waters in lakes and rivers
- 0.001% is water vapor in the atmosphere
Fresh water is only 2.5% of the total on Earth, but two thirds of this water in the glaciers of the Antarctic and Greenland, which are the main reserves of fresh water on our planet. Thus, the water that we have is a very small percentage of the total amount.
Moreover, the melting of glaciers due to greenhouse effect and fever has a strong effect on the environment, both due to an increase in sea level and due to the disappearance of this reserve. In fact, when ice melts, fresh water is mixed with salt water, becoming unsuitable for a person.
For centuries and millennia, the hydrosphere remains almost unchanged, and this is thanks to the water cycle, which allows maintaining the perfect balance in the Earth’s ecosystem.
Hydrosphere and water cycle
The hydrosphere is always in perfect balance and is unchanged thanks to the water cycle. Basically, despite continuous changes in the condition and shape, the water evaporates, and then always returns to the ground. A complex dynamics connecting all 1400 billion cubic kilometers of the planet’s water is called a “hydrogeological cycle” in a continuous cycle, which is never interrupted and supports the perfect balance.
The water cycle works as follows:
- Water evaporates from rivers, lakes, oceans due to heat created by the sun turns into steam and rises.
- Steam condenses in the atmosphere, leading to the appearance of clouds.
- When the clouds reach certain conditions or are too charged, water crystals become larger, acquiring a larger volume and specific gravity.
- Water crystals descend to the soil of the earth in the form of rain, snow or hail.
- Rain, snow or hail feed lakes, rivers and glaciers, partially filtered in the bowels, forming groundwater.
- Water flows from rivers to the sea and returns to the initial situation.
This cycle is in a continuous and ideal balance and thanks to this complex natural mechanism, we can use water resources for energy production.
All the waters of the planets from oceans, rivers, subsoil and atmosphere are connected with each other. Everywhere water circulates and is updated with time. The average time of this cycle is really different. One water molecule for millennia remains in the deepest underground layers. In the oceans, this is a time for hundreds of years; In the atmosphere does not exceed 4 days. Atmospheric waters are completely updated every year 40 times.
How much water is there in the world?
Surface water map - water mass in motion for annual precipitation:
- North America: 18 300 km³
- South America: 28 400 km³
- Europe: 8.290 km³
- Africa: 22 300 km³
- Asia: 32 200 km³
- Australia: 7 080 km³
This means that on each continent there are thousands of cubic kilometers of moving water, only in the form of rains. Water that does not fall into the cycle by evaporation ranges from 45% in North America and Asia to 20% in Africa, where evaporation quota is the highest.
Video: How much water is on Earth?
