There are 7.4 billion people on the planet 鈥� nearly three times as many as there were 60 years ago. The UN estimates that in another 60 years we will be approaching 11 billion. Others say that population will peak soon, then fall gradually as we hit resource limits.
There is another possibility: that hitting those limits causes our surprisingly fragile civilisation to collapse, triggering a global die-off.
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Civilisation may appear robust, but is actually a juggling act. We keep all the balls in the air using densely coupled networks of manufacturing, trade, money, employment, food, water, transport, energy, technology, healthcare, geopolitics and law and order. Each network depends on all the others through many feedback loops.
In other words, civilisation is an adaptive, complex system 鈥� and such systems are susceptible to catastrophic failure. Loss of any essential subsystem can cause the entire edifice to crash, says Yaneer Bar-Yam of the New England Complex Systems Institute in Cambridge, Massachusetts. Even small glitches are big trouble, as we saw in 2008 when local financial failures cascaded though coupled systems to cause the global crisis we are still feeling.
With civilisation itself, we don鈥檛 know what subsystems, or how much loss, would be enough to get us in serious trouble. But we have some idea what might trigger collapse.
If global warming, for example, causes methane release from frozen deposits, we could get positive feedback: further warming, further release and runaway rising temperatures. Farming systems would fail in the face of rapid changes in weather, pests and diseases. Millions would starve. Other major risks are nuclear war (see 鈥�The world in 2076: The anti-science backlash has begun鈥�) and global pandemic.
As well as killing millions, these scenarios could trigger general collapse. Economic systems are sensitive to losing key workers, especially those who are 鈥渉ubs鈥� linking many others, such as truck drivers and oil refinery operators. An epidemic with a death rate like the 1918 flu, for example, would knock out key people crucial to food supply, civil order, transport, electricity and many other support systems. As things come unstuck, ever more people die for ever more reasons, more subsystems fail and collapse accelerates.
Couldn鈥檛 we all just hunker down and go back to business as usual when the storm is over? The problem is that once complex systems collapse, they is that a less complex, alternative stable state from our past would re-emerge. It could be small, authoritarian city states, or even a return to hunting and gathering.
The moral of this story? We need to do something about pandemic preparation, greenhouse gas emissions, nuclear proliferation 鈥� and above all the fragility of a closely coupled global society with little resilience.
Read more: We鈥檝e seen the future, and it will blow your mind
麻豆传媒 is 60 years old this week, so how will the next 60 play out? We look forward to how science and technology might upturn the world as we know it
This article appeared in print under the headline 鈥淲hat if鈥� civilisation collapses?鈥�
