Oraquel » How many liters of water are there in the world?

According to scientists' calculations, there are 1.3 zetta liters of water on Earth (1 zetta = 1,000,000,000,000,000,000,000). At first glance, this number is impressive and may make you feel dizzy, but a deeper analysis shows that water is not equal to water and the vast majority of these resources cannot be used by humans for their needs. This is because:

as much as 97.5% of water resources are salty water from the seas and oceanstylko 2,5% wody na Ziemi to woda słodka,
only 2.5% of the water on Earth is fresh water,approximately 75% of freshwater is trapped in glaciers, polar ice and snowpacks
only 0.007 to 0.5% of all water in the world is drinking water, i.e. free from contamination and safe for humans and animals.

In short - although water covers a huge part of our planet, there are places where drinking it without any restrictions is a luxury available to a few. Moreover, not only African countries, where the climate is hot and unfavorable, are currently struggling with water shortages. Also in other regions of the world, including Western Europe and Poland, water is decreasing year by year, and summer droughts are becoming the norm. Therefore, if we do not start taking care of water, our ecosystem and human health will also be at risk.

How is the amount of water on Earth changing?

Information about the climate crisis and rapidly shrinking water resources in the world has been appearing in the media for a long time and many of us have become accustomed to it. Why? Because it is a problem that does not seem to directly affect us. After all, water still flows from the tap, the shelves in stores are full of bottles of crystal clear liquid, and on weekends and holidays we can still relax by the rivers or lakes. In addition, we often have in our heads another information from geography lessons that the amount of water on Earth has been almost identical for billions of years, because it circulates in nature in a closed hydrological cycle. Unfortunately, there is also a small "but" here. Various factors, such as climate, tectonic movements and, to a large extent, human activity, affect the amount of precipitation, evaporation and melting of ice, and consequently - the form and location of water on the planet. If it ends up in the atmosphere, soil or rivers, it will return to circulation relatively quickly and people will be able to use it for drinking. However, if it ends up in a salty sea or ocean, it will be "stuck" there for a very long time, because the larger the reservoir, the longer the exchange period with other reservoirs. How does it look in practice? Oceans "exchange" water with the atmosphere and land in the process of evaporation and condensation very slowly - water stays in them for about 3,200 years. The average time that water stays in glaciers is from 20 to 100 years, although in Antarctica water from as much as 20,000 years ago is trapped. The residence time of water in other places is as follows:

underground reservoirs - from 10 to 100,000 years
lakes - from 50 to 100 years
rivers - from 2 to 6 months
soil - from 1 to 2 months
atmosphere - about 9 days.

What exactly does this mean?

In practice, this means that there is not only relatively little freshwater, but it is also "trapped" for a long time in reservoirs that are difficult to access for people. In the coming years, it may also become scarce in more and more space. The only way to avoid this threat is to take greater care of the environment and implement actions to protect the climate and freshwater resources. Otherwise, the ability to drink natural water will be reserved only for a small percentage of the Earth's population. And we definitely don't want this, neither for ourselves nor for future generations.