Who Am I?
Ninety years is a long time to adapt, so I think they could get away with a relatively low population, say 1% or so survivors. Depending on how people were alive before the invasion began, that would put the survivors in the tens of millions. That would be enough for an economically sustainable society, with the right technology.
As opposed to losing 99% of the world's pop overnight, which would be an unmitigated catastrophe.
"We learn from history that we do not learn from history."
Ok thanks.
In regards to times and population changes, most of the population drops occurred in the first 10-15 years, however they were spread unevenly across earth with the more powerful nations suffering significantly less. Very few of the cities inhabitants are from the now destroyed regions, most didn't have a chance to flee these areas.
During the fighting a lot of damage was done to the earth (radiation, poisoning, destruction of natural habitats) so as many died from starvation, loss of home as fighting the enemy. The destroyed regions crumbled away rather being quickly wiped out by attacks.
Threads makes the point that, unless the humans really saw it all coming, you could wipe them out in a generation.
But we'll let that slide. Putting them in cities would make them easy targets, and then there's the question of food and farmland (above-ground seems too vulnerable).
...letting those slide, the question is that of genetic diversity and fitness. So a lot depends on how damaged humanity has become through radiation and (childhood) malnutrition, for example.
I think an overall healthy population of 500,000 (Fresno, CA
) in each region would be a working estimate, but that's off the top of my head and assumes present-day tech and productivity. It would also depend on what the density actually is; if everyone is living in fortified cities, or if there are outlying areas as would normally be necessary for agriculture and industry (in which case Tucson, AZ might be a better example).
However, the 'central North America' and 'Far East' regions would have been hit hard by climate change before your timeframe - and likely made worse by the aliens' environmental damage - so I'd research those trends and move them as appropriate.
It'd also be helpful to know just what kind of war, and to what extent, the aliens have been engaging humanity in. Was their first move to reduce human population quickly by directly attacking cities and governmental facilities, or slowly through crop and water destruction? Etc.
The attacking aliens aren't the typical alien invaders, they behave more like xenomorphs from alien. They didn't choose to come to earth but were dumped on earth and haven't been active trying to destroy humanity but have instead been preying on them. They also carry a very infective disease which causes violent behaviour.
The cities exist because the same thing which brought the aliens to earth has also damaged earth's environment, by causing pollution, radioactivity and unusual weather. They function as much as large contained environments as military defences as earth outside the domed cities isn't safe. Most resources are gathered within the cities or salvaged from very nearby (crops and metal), those which aren't are collected at bases built similarly to the cities but smaller.
Most people are healthy, while there are periods of food shortage and much inequality these tend to just result in discomfort rather than serious health concerns. They are careful to control population levels to ensure starvation doesn't occur.
I chose America and East asia as they have the resources and capacity to build such a system and would be less affected by adverse climates. Many poorer regions were destroyed quickly by famine and illness before the aliens even arrived.
The timeline is that the first "attack" was the gradual deterioration of the environment with unpredictable weather, crop failure and then the aliens and radiation arrived 10 years after the start. The cities weren't an immediate response. Humanity attempted to survive outside for as long as possible but when it got too bad they moved into the cities.
edited 18th Sep '14 2:37:58 PM by aoide12
In one of my stories humanity is in the middle of an apocalyptic event but I'm not sure what is a reasonable population estimate for the world. I don't want to estimate too low and make it unrealistic for society to continue but guessing too high makes it feel less threatening.
Background:
It is the mid 22nd century and earth has been under attack from an alien species for ~90 years and humanity is losing. Most of earth is destroyed and humans live mainly in 3 major regions in Europe (UK to the borders of Russia), central America (the central states to mexico) and East asia (China to japan) where they live in giant cities (in between the cities is mostly uninhabited).
Within the setting it is accepted that humanity is at risk of extinction but there are still enough humans to hold onto normal life. Day to day life doesn't feel like the end is coming but everyone knows that any day the aliens could break through. The cities are similar to major 21st century cities (Tokyo, new York) and society is similar to today but with minor advances in technology. There are also more social problems because of the difficulty in supplying essentials and most cities have slum like areas.
Can anyone with a good idea of populations and societies suggest what sort of population levels are needed for such a setting?
Thanks