It is common to hear things like it takes one gallon of water to create a single almond, or watering a lawn can take X gallons per month/year, or it takes X gallons to make one pound of beef or yield X pounds of alfalfa.
My question is, is that water “gone forever”? Or does the water thats used return to the water table/cycle in some other form. When you water the lawn does a large amount of that seep into the ground, evaporate, and return to the atmosphere?
Or is the water used in these ways truly gone forever (in terms of humans being able to use it again)?
You can’t destroy it and it doesn’t go anywhere. It just gets moved around and used for different things at different times.
Water lawn > Grass uses water to grow more grass > humans mow lawn > grass clippings dry out > water returns to atmosphere
If everyone on earth died at once and decomposed, how much water would be returned to the environment?
Very little, tiny fractions of a tiny fraction of a percent of the water on the planet.
Maybe a few years, once the ISS crashes down to earth as that is one of our greatest of planet reserves
What about something like electrolysis where it’s separated?
If you keep them separate sure, but the moment you burn hydrogen it just turns back into water.
So then the truth of the matter is that we can create water from hydrogen and oxygen and we can also destroy water by reducing it to its elemental compounds. As such, water can be created and can be destroyed, meaning that the overall level of water available on earth can change over time, however our commonest uses for water have it not be destroyed and eventually return to the water cycle.
Technically, yes.
Realistically, any amount we split/convert is so small as to not matter to anything. The amount of water on the planet is absolutely ridiculous. 1233.91 quintillion liters to be more specific.