My understanding is the population estimate for 300 AD was ~1 million, declining to ~800k in 400 AD, ~500k in 450 AD and down to ~100k in 500 AD.
It’s the timescale that makes it. I’m thinking Methyr Tydfel in the UK as a point of reference for similar fractional change in the first roughly century of decline, but peaking in the Industrial Age.
If this happened in NYC, I’d expect (say) Queens to turn to rubble while (say) Manhattan is getting freshly built skyscrapers. Plucky adventurers with assault rifles and bows looting tinned food from a suddenly abandoned Whole Foods is more of what I expect during hurricanes than as a standard result everywhere all at one.
Re:A Compass for the Politics of Collapse
by inglor_cz on Tuesday August 31, 2021 @03:04AM
(#28364781)
I think the bottom was reached around 800 AD with 20-50k people in entire Rome. Admittedly, it is not easy to estimate population development in a city like Rome that has been built several times over and people still live above the ruins. It must nevertheless been quite obvious to the early medieval inhabitants of Rome that the city used to be far bigger, far more populous and far richer.
If the same happened to New York, with the subway abandoned, whole neighbourhoods overgrown by poison ivy and the skyscrapers collapsing from lack of maintenance, "post-apocalyptic" would probably be a fitting word.
I am not sure how you can call such a massive loss of complexity and population something else than a collapse.