Hydrological cycle

The amounts of water that are moved through the hydrological cycle can also be estimated and evaluated in numerical terms. The tool we use is the global hydrogeological balance of the Earth. The total amount of water that evaporates from the surface of the oceans is more than the water that gets straight into them from precipitations. The difference is part of the amount of water that falls down on the continents. The total amount of water that falls on the continents actually consists of that which has evaporated, not only from the seas or oceans, but straight from the soil as well. The global hydrological balance differs according to climatic conditions – especially the extent of precipitations – and is different, therefore, in each region of our planet. If we take, for instance, the equatorial climate, we can see that there are no water shortages during the year: there is always plenty of water available since the precipitations can easily cover the losses. Conversely, in the hot desert climate, the high temperatures promote the evapo-transpiration that the few precipitations cannot make up for: in this case, there are serious shortages all through the year and little water available. The differences found between the hydrological balances of these two types of climates have immediate repercussions on the vegetal and animal species that live there, whose survival is closely linked to the amount of water that is available and usable.

Special reports

  • 15 April 2014

    How rich are we …. in blue gold?

    Water footprint, water availability and use on a planetary scale...

    26 February 2014

    How much water is on your plate?

    Water footprint and water consumption...

    8 July 2022

    Who’s coming to dinner

    A shark in my hamburger Summer is finally here! As usual, we have waited for it all year long and…

  • 13 May 2018

    Small steps, great footprints

    Have you ever wondered how much space is taken up by an apple or a steak?...

    7 October 2021

    Water grabbing

    “Clear, sweet fresh water,” wrote Petrarch, by many considered a precursor of Italian literature. Before him, St. Francis dedicated two…

    17 May 2021

    Lost ice

    According to a study conducted by a French and Swiss research team recently published in the leading journal Nature, continental…

  • 15 April 2021

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    The invisible invasion of microplastics...

    26 December 2019

    Life in Antarctica

    How is it possible to live and work in Antarctica...

    10 December 2019

    In the fridge of the world

    Antarctica is a continent with a very particular charm...

  • 15 April 2014

    How rich are we …. in blue gold?

    Water footprint, water availability and use on a planetary scale...

    26 February 2014

    How much water is on your plate?

    Water footprint and water consumption...

  • 8 July 2022

    Who’s coming to dinner

    A shark in my hamburger Summer is finally here! As usual, we have waited for it all year long and…

    13 May 2018

    Small steps, great footprints

    Have you ever wondered how much space is taken up by an apple or a steak?...

  • 7 October 2021

    Water grabbing

    “Clear, sweet fresh water,” wrote Petrarch, by many considered a precursor of Italian literature. Before him, St. Francis dedicated two…

    17 May 2021

    Lost ice

    According to a study conducted by a French and Swiss research team recently published in the leading journal Nature, continental…

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Facts