Much has been written, and continues to be written about the die off rates after a societal collapse. The truth is there is no possible way of knowing, and stating figures is pure conjecture. It’s the facts that need looking at.
There are many things that can happen to cause a collapse, but only two of those things, in my opinion, will have the remotest possibility of causing a mass die off of the human race. Total failure of the grid and a pandemic of a killer disease. Both of these things could have origins that are the result of natural occurrences, or that are man made. The origin of the cause is not important from the medical point of view, what is important is the effects it will have and how those effects can be dealt with.
A pandemic is an epidemic that has spread around the globe. The damage caused to the population depends on the disease, it’s mode of action and it’s morbidity and mortality rates. It is not automatic that a pandemic will kill millions, there are many variables that come into play that can alter the course of a pandemic, making it far less, or far more severe than was first thought. Novel H1n1-swine flu, highlights this point. It hit young healthy people the hardest, as did the 1918-1920 pandemic which was very similar in structure but was far more severe in nature than the 2009 pandemic.
Flu pandemics often come in three waves, sinusoidal waves corresponding with the flu season in a particular part of the world. For some reason, as yet unknown, the second wave, the second flu season is often worse than the first. The third wave sees far less deaths and by year four, there have been enough people who have survived it for there to be passive herd immunity and the flu subset becomes integrated into the range of flu viruses in circulation at any given time.
In order for a localised outbreak of a disease to turn into an epidemic, and for that epidemic to turn into a pandemic, the disease needs to be able to be passed from individual to individual with relative ease. The population, or the herd as it is referred to need to be close together, like in a city, in order for the disease to have enough hosts to spread into. The basis of vaccination is to provide herd immunity and therefore deny the disease a supply of suitable hosts, thus preventing an epidemic, and by default a pandemic. This is referred to as active immunity. Active immunity is not foolproof. Janet Parker, from Birmingham, West Midlands UK died of smallpox on September 11th 1978, she had been vaccinated against the disease in 1966. The Abid strain that killed her was rare and had not been discovered until years after she was immunised and therefore she was not protected. She was the last person to my knowledge to die of Smallpox. Her mother contracted the disease from her but survived the encounter.
For a pandemic to truly get to the point where mankind would be threatened it would most likely be an emerging disease that is either novel, as in not seen before, and would have to have a high morbidity and mortality rate, or a known emerging disease that as yet has no cure, vaccine or treatment available. Again it would have to have a high morbidity and mortality rate. Zoonotic diseases, those passed from animals to humans feature highly on the suspect list.
It is of course possible that a pandemic could be triggered by a pathogen escaping from a lab, or by a deliberate release. It is however considered by the medical profession to most likely be caused by just one person with a highly contagious condition, doing something completely normal like teaching a class of kids or arriving at a major international airport. Even this though does not guarantee a disease going global. Many lethal diseases, such as Ebola, have such blatant symptoms that although some people in direct contact would die, it is highly unlikely to be more than a localised incident, almost immediate containment would see to that. If any contact did go on to develop and spread the disease, containment again would kick in. There would never be enough hosts for it to get a foothold.
This is what happened in the Parker smallpox case, although highly contagious, swift treatment and containment limited the spread to two people, including Parker, and the other patient survived.
Microbiologists, virologists and bacteriologists around the world are in consensus that the biggest risk for pandemic comes from respiratory disorders. This is quite simply because they usually start off feeling like a cold, and progress to feeling like flu, by the time anyone is aware that it is a novel illness, many, many people are already infected and are passing it on to others. Microbiologists work on a 20 spread, that is each person with a highly contagious condition will infect approximately 20 people, the rest of those they come into contact with for some reason do not develop the condition. So, one teacher infects 20 kids, over the next day or week, depending on the disease, each of them infects 20 people, that takes us to 400. Each of those 400 infect on average 20 people each, that gives us 8000, and so on, you are now heading towards an epidemic. Global travel is an easy way for epidemics to turn into pandemics, if populations were static, pandemics would not occur. Even the plague pandemic in the middle ages arrived by sailing ship, it escaped from its local population and spread out.
There is no way to prevent a pandemic of an emerging or novel disease. The impact can be minimised by international co-operation on research and drug development but that is all. On an individual or family level, social distancing, that goes way beyond the government guidelines of not going to a ball game or to the cinema is the only effective way to deal with the situation. If you are not sharing air with people who may be infected, not touching the door handles that they touch, not sitting on chairs they sit in or telephones they have used, you greatly reduce your risk of becoming infected. Many pathogens can survive for 72 hours on hard surfaces, and 24 hours on soft surfaces such as bed linen and towels.
The flu pandemic of 1918-1920 killed between 30 and 50 million people, with some 675,000 Americans amongst the dead. The global population at that time was approximately 1.8 billion, so some 3% of the population died, and 500,000,000, or 27% were infected. Today the global population stands at 7 billion. If 3% of the population died in a pandemic, some 210,000,000 lives would be lost globally. Whilst a vast number, it would in no way wipe out the human race. If 30% died, that’s 2.1 billion
people, we would still have 4.9 billion neighbours, more than twice the amount alive in 1918.
Whilst it is not disputed that a major pandemic would be devastating, it is unlikely, at this point in time, to result in the extinction of the human race. That said, it should be noted that small nations could find themselves much more sparsely populated, and in some cases totally depopulated, after such an event as proportionally they may lose more of their inhabitants.
Losing five million people out of the 336,000,000 residents of the USA would be unthinkable, losing 4,895,000 people from Norway, leaves the country devoid of human life.
Looking at the bleakest possible scenario, a new, highly virulent diseases emerges and takes the world by storm, killing 90% of the global population. It is still highly likely that as a race we would survive. Something that new and that contagious would likely see countries blocking international, and maybe even interstate travel, this is purely a damage limitation exercise. That done, it would be expected that pockets of the world, the remoter areas of the planet would see humans surviving the disease, and even those living a remote lifestyle in large countries like the USA, Canada, Australia etc would have a good chance of surviving if they prevented contact with outsiders.
This bit needs a book all to itself but I’ll give it a go.
Depending on the severity of the pandemic, the aftermath will range from carrying on as normal whilst mourning people we may have lost, to a total infrastructure breakdown whereby normal services can not be resumed due to lack of people to run those systems.
A docudrama, shown in the UK two years ago called ‘Life After People’ looked at how long the planet would take to revert to nature if mankind were to simply vanish. They talked to experts about how long the bridges would take to fall down, the subways to flood etc. It seems the Hoover dam could keep running, with no intervention from humans for a year or more as it is mainly automated and there are so many turbines that even one or two breaking down would not mean the whole system fails. That’s the only example I have of something that is infrastructure related continuing to work without humans.
For those that survived the worst case scenario event, life would be extremely difficult. Many would have no family or support mechanism, the infrastructure has collapsed, unburied bodies lie in houses and hospitals all over the country. Packs of dogs roam the streets and vermin are spreading disease. These people would be refugees in their own land, and their only choice would be to migrate away from these areas if they wanted a shot at long term survival.
The only real plus for these survivors is that long term food supplies would be plentiful and there for the taking, fuel for cars and generators would be easy to come by, and medical supplies would be available in abundance. Having these things would give them a better chance than past generations of starting new colonies and settlements, and providing the gene mix was varied enough, it would be these groups that would, over many generations, repopulate the planet.
We have no way of knowing, should a pandemic occur, if it will be the worse case scenario or not, but, if looking at all past pandemics gives us clues to the future, future pandemics will fall somewhere between the worst case scenario and the 2009 pandemic, which for those of us untouched by it, was very much a good result, for most of us it was a mild disease with no lasting effects.
Research on novel, emerging and re-emerging disease continues around the world in the hope that when the time comes, and it most certainly will come, we have the ability to fight back. The real issue is not knowing what you are fighting against. Mother nature is a master of disguise, and something that effects only pigs today, could infect humans tomorrow. Something affecting only birds on Wednesday, could make the leap to humans on Friday. It is these zoonotic infections that most respiratory diseases arise from, and almost all flu infections started in animals and birds before making the jump to humans. As I said, you can’t stop these diseases spreading, and the only real advice is stock up, be aware and prepare…it’s all you can do.