Things have changed since my childhood. I’d guess cell phones are behind it. I’d have had to walk my bike home.
Going back to the decline of ancient Sumer, it’s my understanding that persistent drought is only one of several possible scenarios, with persistent drought being one of the more speculative. Dry summers and dependence upon floodwaters due to snow melt running down out of Turkey has always been the case. The shift from wheat to barley that is evident in archaelogical research and in cuneiform tablets, would seem to indicate salinization of soil over time, due to heavy reliance upon flooding and/or irrigation.
Actually, it goes back much, much further than that. Between 11,000 to 10,000 years ago in that area, there was a drought that lasted 1000 years.
From about 13,ooo years ago there had been warming, with acorn-rich oak forests spreading, surface water in the form or lakes and springs appearing, and hunting bands from the southeast migrated into the area of present day Syria. They eventually established communities based on gathering nuts from the oak and pistachio forests that stretched from the Euphrates River basin through Damascus and down into the Jordan River valley. After a couple thousand years communities had been established and populations had grown.
The drought hit these people very hard.
(The area of today’s Persian Gulf was dry land between 18,000 to 14,800 years ago. It did not flood with sea water completely until about 5,500 years ago, after which it subsided a bit. Pre-flood it was a low lying valley with a river running through it to below the present Strait of Hormuz. The Euprhrates and Tigris rivers join together before entering the present day Gulf waters, but underwater mapping has shown where two other rivers, now extinct, once joined with the ancient single river. This fits with the ancient Hebrew description of the Garden of Eden being located on a river below the congruence of four rivers.)
Sources for this information can be found in UNDERWORLD, by Graham Hancock (chapters 2 & 3); and THE LONG SUMMER: How Climate Changed Civilization, by Brian Fagan (chapter 5). Warning! These are boring books.