One of the most dangerous threats to the human future in this, the Age of Perils, is … optimism.

Nowadays, if you tell the tested truth about climate science, weapons of mass destruction, global pollution, extinction or, indeed, any of the ten existential threats now closing in on humanity, you are likely to provoke one of two responses.

The first is a sober “Shit. I never knew it was that bad. What’s the evidence?” followed by “What can we do about it?”

The second ranges from polite dismissal to “I don’t want to hear all that bad news”, to outright, hysterical abuse, in which you are labelled everything from a “doomsayer” and a “Malthusian” to a spreader of lies, a “greenie nutcase” or even a socialist, a Marxist or a contemptible liberal!

Human society neatly divides into folk who can handle bad news – and those who can’t. Those who put their hands over their ears and demand you shut up. Or, as Charles Darwin might have observed, those who are fit for survival – and those who ain’t.

How do I know this? Well, as a newspaper editor, I once decided to test the old theory that the media favours bad news over good. So, for three weeks I published nothing but good news in my paper – and watched the circulation slide by 15 per cent! When I restored the usual ratio of 60:40 bad news to good news, the circulation returned to normal. I concluded from this minor experiment that it was the public, not cynical old editors, who prefer the bad news.

That set me wondering why humans, as a species, may favour bad news over good. As a science writer who has closely followed human prehistory, a reasonable explanation wasn’t hard to find. We don’t prefer ‘bad’ news: we need to know about it in order to survive, to overcome looming threats or to exploit changing circumstances. Not reacting to bad news means more deaths from disease, conflict, famine, pollution, violence, etc. It means the leopards will keep on eating the kids.

That’s what happened about 1.5 million years ago at a place called Sterkfontein, South Africa. Two child skulls were discovered in a bone pile of what was evidently the lair of a now-extinct form of leopard. Indentations in the rear exactly matched the leopard’s lower canine teeth, indicating it had dragged its prey around by the head.

Within almost the same archaeological layer appear lenses of ash and charcoal: pre-humans have discovered the use of fire.

It’s a safe bet they didn’t discover it in order to compete on Master Chef. Prehistorians generally accept that pre-humans overcame their own fear of fire because they observed that leopards and other predators were even more frightened of it than they were. After millions of years of being dinner it was finally: Prehumans 1, Predators nil.

However, to use fire you have to do several remarkable things:

look into the future and anticipate being eaten by leopards;

have the foresight and courage to collect fire after a lightning strike and bring it back to the home cave or shelter; and

collect a supply of fuel and feed it constantly, 24/7/365, as you don’t have any matches.

Wisdom is commonly defined as “the ability to think and act, using knowledge, understanding, common sense and insight”. That’s what our ancestors exercised in the case of fire – and it is clearly what we must do to overcome the far greater risks of climate change, nuclear holocaust, ecological collapse, a poisoned planet, perilous new technologies and an exploding population with unconstrained demand for limited resources.

That little rocky hill in southern Africa marks the birthplace of wisdom. It is a solemn reminder of what we now need to do, as a species: be wise.

So how is it that humanity was able to assess and solve existential threats back then, when we were barely brighter than chimps – but seeks to demean, decry and punish those who warn us about the far greater threats which now surround us? How come Donald Trump is trying to destroy the scientific knowledge base that informs our ability to act in the interests of our own survival? How come Abbott and Turnbull have carefully positioned Australia as a do-nothing country, incapable of acting in its own self-defence against existential risk? How come 100 of the world’s largest companies are seeking to drown humanity in false information that will ultimately destroy themselves, as well as us?

Some academics have argued that the public should be sheltered from the facts about the size of the risks now confronting us. Many people, self-described ‘optimists’ especially, are unable to handle bad news and simply block it out, while others are depressed and paralysed by it into a state of indecision, inaction and helplessness, they say.

Optimism can be a useful attribute in a general, a politician or a business manager, providing it is based on fact, not mere belief. It nurtures the resilience to endure tough times. But remaining stubbornly “optimistic” when the weight of evidence points to imminent dangers to civilization and maybe even our species is a formula for disaster, that spells inaction and, consequently, an increase in the scale of the risk. It decreases our fitness for survival. It is, in short, extremely unwise.

Many “optimists” insist that humans are so smart we will come up with technical solutions to all the leading threats we face (though how we can do this with nuclear weapons is a moot question). And it is true that technical solutions exist to most of them. However, this ignores the fact that many of our greatest institutions – governments, corporations, faiths – are unable or unwilling to take action until the threats become so vast as to be unstoppable. The technical solutions will not develop unless society sees a need for them.

In this case it is the blind optimists, rather than the realistic pessimists, who imperil our future.

An important departure from traditional blind optimism is Pope Francis’s encyclical Laudato Si, which basically argues that if humans don’t take better care of the planet, it won’t be able to take care of us. It’s a case of one far-sighted, wise man, trying to move a conservative institution into taking the actions essential to survival. It has set a fresh example and possibly charted a new course for the world’s faiths, which are largely stumbling in the dark. What the world needs most at this critical juncture are political and business leaders with similar wisdom.

A handful of Governments – Germany, Denmark, Sweden, Norway, France, possibly China – show signs of awareness of the tenfold risk we face, and the need for universal collaborative action to solve it. And likewise, a handful of corporates realise that future profits depend on business models which are sustainable, and which don’t wreck the resource or skills base they depend on. These are wise realists, not pessimists. They have a general grasp of what is coming down – though maybe not its magnitude or speed. And they are willing to take action (though many scientists would argue it is far too little and far too slow).

Whether you self-define as an optimist, a pessimist or something in between, you, your children and grandchildren now face threats on a scale never before seen in human history. Inaction, and denying or burying evidence, will only increase the toll these threats take on us. As the US military has already warned Trump.

To overcome them humanity doesn’t need optimism or pessimism. It needs to exercise a singular attribute that has stood us in good stead for over a million years: wisdom.

Julian Cribb is a science writer and author of Surviving the 21st Century (Springer 2017). He is optimistic about the ability of humans to solve our problems but pessimistic over the capacity of our institutions and leaders to do so.

The MAHB Blog is a venture of the Millennium Alliance for Humanity and the Biosphere. Questions should be directed to joan@mahbonline.org

MAHB Blog: https://mahb.stanford.edu/blog/optimism/