Now answering your question in what exactly would happen if we had no water: Well... Imagine all human beings need water to sustain themselves and hydrate the body and with no water we could easily die of thirst, second of all, all the fish and water creatures on rivers, oceans, etc. would die, etc. And water cannot be replaced by another substance or liquid. To add the global population is always increasing. As populations grow so do demands for water. People have to be fed, and agriculture must have water to grow crops and livestock. Without water flowers, trees, etc. would dry up. We humans would have nothing to eat. With no water, we wouldn't just die of thirst but also starvation since plants need water.
However you must have no fear of that ever happening because to us human beings awaits a grand future. Imagine a world without pollution or contaminations, lions will lie next to the sheep, the cobra will play with a child, all animals will be at peace with humans, etc. All these things will happen. How? I suggest you go to JW.ORG for more info on this. JW.ORG also helps when it comes to questions such as: what is the purpose of life? What happens when we die? Does evolution exist? What is the key to true happiness? Why do we suffer? And finally what future awaits for us human beings? It also gives some advice to questions many teenagers ask.
Hope this answers for question.
