The earth's surface consists of 70.9% water and 29.1% of land. As a result, the earth from space looks blue.
The water is distributed :
Seas and oceans 97.2%
Ice caps and glaciers 2.15%
Deep groundwater 0.31%
Superficial groundwater 0.31%
Capillary water 0.005%
Rivers 0.0001%
Saline and brackish lakes 0.008%
Freshwater lakes 0.009%
Water vapor in the air 0.0009%

Only 0.03% is available for consumption (accessible and not too dirty).
About 90% of the world supply of fresh water is located in Antarctica.
A large part of the people must walk at least 3 hours to get water.
Every day almost 10,000 children younger than 5 years die in Third World countries as a result of diseases by drinking impure water.

How much deeper would the ocean be without sponges?