What's the ultimate exit strategy if the worst happens? Like a sudden global pandemic, or some other kind of existential crisis that threatens humanity with extinction?
The sad truth is, if an apocalyptic outbreak comes, there may be no escape. But if you're in the right place when the catastrophe hits – like an island naturally isolated from the spread of contagion, say – you might be able to ride out the storm and help humanity rebuild in the aftermath.
With these cheery prospects in mind, scientists have identified and even ranked what they say are the best potential island refuges in such a crisis: places that might best ensure long-term human survival in the face of catastrophic pandemics and other potential existential threats.
It may sound like something out of a dystopian sci-fi movie, but the team warns that the dangers, while not imminent, are entirely plausible.
"Discoveries in biotechnology could see a genetically-engineered pandemic threaten the survival of our species," says public health physician Nick Wilson from the University of Otago in New Zealand.
"Though carriers of disease can easily circumvent land borders, a closed self-sufficient island could harbour an isolated, technologically-adept population that could repopulate the Earth following a disaster."
To identify the most effective refuges in this kind of crisis, the researchers didn't consider small islands. While isolated pockets of people might very well survive without assistance, tiny populations without a diverse range of technical experts wouldn't be able to effectively rebuild and recreate a modern technological civilisation, the researchers say.
Because of this – and the ultimate ambitious scale of rebuilding society – the team only considered independent sovereign states recognised by the United Nations, without any shared land borders with other states (and not connected to other nations by bridge), and with populations of over 250,000 people.
Beyond this, the researchers also had to take into account other features that would make for an effective island refuge in a doomsday scenario: population characteristics, the refuge's physical location, availability of natural resources, and the political and social features of the society.
When they scored nations on these attributes, they came up with a list of 20 places that make the most effective island refuges, but three in particular stood out based on their scores (an average from 0–1).
"The island nations of Australia (0.71) followed by New Zealand (0.68) and Iceland (0.64), appear most likely to have the features required to act as an effective refuge in the face of a catastrophic global pandemic, from which large-scale technological society can be successfully rebuilt," the authors write in their paper.
Aside from those three, all the other hypothetical island refuges in the top 20 scored less than 0.50, making Japan, Barbados, Cuba, Fiji, and Jamaica and many others ultimately less suitable for securing humanity's survival.
"Somewhat unsurprisingly, it was nations with high GDP, that are self-sufficient in food and/or energy production, and are somewhat remote, that fared best," the researchers explain.
Some countries might be able to improve their rankings if they can increase their food and energy production, the team says, whereas other island nations may be stuck in place, due to their political instability, or exposure to things like natural environmental hazards – which don't look good when scoring the ability to rebuild human civilisation.
"This will require post-catastrophe mobility, extensive resources, and a large population that can spread around the globe again," the authors write.
"Several of the island nations that were examined lacked independent resources, including energy supplies, and also lacked the social capital and political stability to make effective post-catastrophe cooperation likely."
The researchers acknowledge that their methodology may include a number of shortcomings that can be refined in further research, and say the ramifications of future climate change need to also be considered in more depth.
Hopefully, we'll never need to rely on a gloomy ranking like this, but that doesn't mean it's not extremely important to weigh up our options.
"It's like an insurance policy," Wilson says.
"You hope that you never need to use it, but if disaster strikes, then the strategy needs to have been in place ahead of time."
With that in mind, you now know the best places to ride out the viral, bacterial, or perhaps fungal apocalypse – knowledge that may well be enough to make you want to migrate. If that's the case, don't delay in getting your affairs in order.
Previous research from the same team concluded that complete border closures by island nations in the face of extreme pandemic situations were "probably warranted". So if you're thinking of bolting to a bolt-hole, bolt quick.
The findings are reported in Risk Analysis.