Is there a constant amount of water?
Question
Does the amount of water in the world remain the same, or does it increase and decrease? If it's the same amount, why do we have water shortages?
Ralph
Answer
** Definitive **
Name: John
Qualification: Chemist
Answer: When you start your car, you see steam coming out the exhaust pipe. When you burn hydro-carbon fuels, you mass-produce water and carbon dioxide. Equally, if you electrolyse water, you can get hydrogen and oxygen. So it can never be a simple balance - it would depend on how much fuel is burnt and how much you produce hydrogen and oxygen. Therefore, there is no precise balance of water. Water shortages aren't a lack of water - it's that the water is in the wrong location.
Name: Alex
Qualification: At Exeter University
Answer: The global hydrological cycle is a closed system. It does not have external inputs or outputs. There is therefore a fixed amount in the Earth's atmosphere, in whatever state it might exist.