That gallon of water used to water that tree right now is not available to me to shower, drink, or flush right now. The water becomes immediately unavailable u

That gallon of water used to water that tree right now is not available to me to shower, drink, or flush right now. The water becomes immediately unavailable until it returns to the ground as rain somewhere or someWHEN else. Sure, looking at the big picture the water is never actually "lost". Until you can plumb my domestic water into the clouds directly, the big picture is irrelevant. All that matters is the water that is available in a potable form for me to drink right now. In financial systems, we might come to an arrangement that I will pay you Friday for a burger Tuesday. With water, it doesn't work like that. If I don't have water now at the time I need it, there is no use promising me water late next week. And when it comes to a decision between me having a litre of water today for me to survive on, or saving your thousand-dollar almond tree, I will unashamedly pick me.