So the moment that the important gas distribution system is de-pressurised, the grid-balancing system fails and power cuts ensue.
It’s unimaginable to gauge how extensive these power cuts can be, however the grid can be so seriously compromised, possibly fatally, that they might be widespread and everlasting.
Electricity demand would have rocketed through the switch to electric space heating, cooking and water-heating, and so it seems very likely that the sudden excess demand can be undeliverable, and subsequently that the grid would spiral into uncontrollability.
No electricity means no communication systems – no mobiles, no TV, and no running water. With no power and no heating, vulnerable people begin to die.
Initially just the elderly in their very own homes, then in hospitals when the diesel back-up generators run out of fuel, but then recent existential problems emerge for abnormal people in the shape of food availability and distribution.
Day 25 – I’m probably being generous with the timing here, but diesel and petrol are prone to have run out by day 25. Which means that food distribution would fail, and so the population, most of that are entirely depending on bought food, begin to starve.
In dire national emergencies, international help is usually forthcoming, but on this case, this scenario is happening, in largely equivalent ways and timing, across the developed and developing world. Only isolated rural communities, agriculturally self-sufficient, can be relatively unaffected. So no international rescue mission.
Day 50 – within the urban world, many individuals can be near death from starvation. Within the 50 days because the ending of fossil fuel supply, law and order would have broken down, and I think that mass conflict and slaughter would have been happening with the increasingly desperate seek for the technique of survival.
But disease can be on the rampage too, with no power, no water supply and no sewage flow, so cholera, dysentery and all the opposite Victorian diseases of crowding would take over.
Day 100 – just three months or so because the world just stopped oil – my guess is that around half of the world’s population (say 4 billion people) can be dead. The primary to die can be the urban poor; then the center and upper classes, with money and standing becoming increasingly irrelevant with the passage of time.
The survivors can be largely rural, in a position to live off local agricultural produce, or live off dwindling food stocks.
Accessing food and secure water for urban dwellers (about 55pc of the 2023 world population) can be nigh-on unimaginable, as all the conventional distribution routes for food would have failed, and storage facilities (chillers/freezers) would even have failed without electricity.
Pumped water can be unavailable, so access to wash water can be near unimaginable.