Hydrosphere - The Earth's Hydrosphere

The terrestrial hydrosphere is one of the three instances that form the biosphere terrestrial – together with the lithosphere and the atmosphere. This is the set of water resources that make up our planet, including water in the oceans and rivers, the frozen waters of the poles and mountains and also the water present in the atmosphere in the form of steam.

Although planet Earth is abundant in water (70% of its surface) and although this resource is considered renewable, the availability of water becomes problematic. water resources on the planet, both for its distribution and for the small proportion of its own form of consumption: drinking water.

Of all available water, 97.5% is salty and 2.5% is fresh. And if we consider only this fresh water, 68.9% of the total is retained in the polar glaciers, with 60% on the Antarctic continent. Furthermore, 30.8% is in the soil and underground reserves, so that only 0.3% is available in rivers and lakes, many of which are now polluted.

In this sense, the entire problem surrounding the drought faced in various places emerges. After all, the total volume of existing water on the planet practically does not change over time, whereas what changes is its form of availability. With the pollution and, in some cases, extinction of rivers and lakes, in addition to the depletion of aquifers in several countries, many regions are experiencing dramatic situations for access to water.

In the midst of this debate, the concept of hydrical stress, when referring to those countries that consume water at a rate higher than the natural replacement capacity through its cycle. Some countries need to resort to importing this resource and to techniques such as desalination. Even Brazil, recognized for the abundance of its resources, is not free of this issue, since that most of the existing water in the country is found in less inhabited regions in the north and Midwest. Not by chance, the state of São Paulo, a few years ago, faced a severe water crisis.