Potable water is a passion of mine. Specifically calling attention to the fact we're running out of it, and without it there is absolutely nothing. While reading an article about an ocean of water beneath the earth which may be three times the size of all the surface water in the world including the oceans.
I saw this side-bar.
While this is not the result of natural catastrophe or climate change, it will preview how it will start: One side controlling this resource vital for the lives of millions. It will end with a short ferocious war, killing countless people. Then the deaths from famine and disease will make that look like a trifle.
Sooner or later, this scenario will repeat itself. On the Himalayan/Tibetan plateau the glaciers are vanishing. There are seven great rivers which rise there and hundreds more which are vital to billions of Asian people.
Anyone remember Stephen King's "The Stand"? Remember "Captain Trips"? I saw an article about a Japanese team which genetically modified the "Spanish Flu" strain, which killed tens of millions of people in 1918-1919. They made it even MORE deadly.
I hate to be speculative beyond the likely. But I wonder how long before an emergent virus or drug resistant bug is part of a cascade of events such as prolonged drought and water shortages, conflict, famine -then pandemic?
I have at least positioned my genetic legacy where there will be water for at least 50 years.
I believe it will be a crap-shoot who what and where any of us survive the storm I believe is coming. This may be to some -even most- to be some paranoid fantasy of mine. Maybe it's a case of "truthiness". But I believe we've poisoned ourselves and have been whistling past the graveyard for decades.
Look around you.
Do your best. Try and save what you can in the next fifty years.