Imagine that an American bomber jet has an accident whilst flying over the coast of Andalusia. Imagine that the plane has thermonuclear bombs on board, each one with a destructive power 100 times greater than the Hiroshima bomb. Imagine that three of those bombs fall to the ground. Well, actually, this has already happened. Let’s talk about existential risks.

In the last episode of AltruPhysics we talked about the end of endings: the ultimate destiny of the Universe, we saw that the Universe will most likely continue to expand forever, eventually freezing into darkness. And we also saw that, long before that, the Sun will start to fry us alive, turning the Earth into an uninhabitable ball of fire. Therefore, we concluded that life, on Earth and beyond, sooner or later will end.

Even so, there’s still a billion years to go until the Sun starts to get angry, so we have plenty of time left to enjoy this planet, our beloved blue dot in the immensity of the cosmos.

Now, the death of the Sun is not the only danger that awaits us in the future; there are many others that threaten the Earth and humanity. And they are not hypothetical risks in the distant future. Some of them could even happen during the course of our lives, if we do not take the necessary measures.

In fact, as we will see at the end of this episode, during the last 70 years humanity has already experienced several incidents that could have led to an absolute collapse. So far we have been lucky, but that may not always be the case.

This will be the first of a series of episodes dedicated to existential risks.

What are existential risks?

Let’s first clarify what an “existential catastrophe” means. And to do so, I’m going to rely on the book The Precipice, by Toby Ord. According to this book, an existential catastrophe can be any of the following 3 scenarios:
1. The extinction of humanity: Humanity disappears forever. This could happen, for example, with the impact of a large meteorite, or an alien invasion in the style of Independence Day (in which the Americans don’t end up saving the world on July 4).
2. An unrecoverable collapse: Humanity does not disappear, but it is greatly affected to the point of never being able to recover current levels of well-being. For example, this could happen if the environment deteriorated so much that it made Earth virtually uninhabitable, aka what happens in Mad Max.
3. An irreversible dystopia: Humanity does not disappear either, but gets trapped in an absolutely horrendous existence. This would happen, for example, if a totalitarian regime were established in the world, imposing a constant global slavery with no escape, in the style of 1984, or practically any chapter of Black Mirror.

Climate disaster, emptyness and dry soil
Photo from Pixabay.

So, an existential risk is any danger capable of causing an existential catastrophe. In other words, it is anything that can end all human potential, rendering the world a place not worth living.

Are we headed towards the precipice?

Perhaps you are one of those who think there is more and more violence, more pollution, more inequality, more injustice and more death, so it’s obvious that society is already headed towards a dystopian future. If you think so, let me tell you that you are partially right, but mostly wrong.

The truth is that there are many reasons to rejoice in our society and to have hope in humanity. For example, thirty years ago, 36% of the world’s population lived in extreme poverty (that is, on less than $2.15 a day). Today, however, it’s less than 9%. The percentage of the illiterate population has been roughly halved and we could give many other clear examples of progress. So society, broadly speaking, is progressing rapidly and substantially, which we will talk more about in future episodes of AltruPhysics.

But an existential risk doesn’t have to be foreseeable. Instead, it can appear out of the blue, and have irreversible effects. For example, we could live in a world free of war, poverty and hunger, but suddenly and without warning, be struck by a terrible pandemic, capable of causing our extinction.

It’s also true that other risks can be foreseen, but they are very difficult to avoid. For example, climate change has been under investigation for decades. And yet we still haven’t yet managed to activate a plan capable of preventing an irreversible environmental catastrophe.

So, are we headed towards the precipice? No one can know for sure. What we can do is try to estimate the magnitude of these risks, and prepare to face them.

Are we prepared?

As of today, we don’t have a clear strategy for what to do if a large enough asteroid (more than a few kilometers in diameter) were headed straight for the Earth. Although there are several proposals on the table, including bombing the asteroid with Hollywood-style nuclear warheads, we still don’t have a safe solution. We can say that the first planetary defense mission in history occurred just a month ago, when NASA crashed a satellite into an asteroid to test if we would be able to divert the trajectory of a potentially dangerous object. In other words, our knowledge of planetary defence is still in its infancy.

But the impact of a large meteorite is only one of many possible existential risks. In fact, the probability of such an event happening in the next 100 years is relatively low. There are other risks that are up to 100,000 times more likely. And, paradoxically, some of those risks are much more neglected.

One of them is already familiar to us: The risk of a pandemic. Even when there were already voices warning of this danger years before it arrived, COVID19 caught us by surprise. While it’s impressive that effective vaccines were developed in record time, it’s also true that the lack of global coordination has had an enormous cost in lives.

But the situation could have been much worse. For example, the omicron variant, which turned out to be considerably more contagious than the previous ones, could also have been more lethal. So we can consider ourselves lucky this time.

So no, all in all we are not ready. But perhaps you think that we’ve learned our lesson and that from now on we will be better prepared. Is that really the case?

Are we getting ready?

Preparing against existential risks is an expensive and long-term investment. Of course, experts say that preparing for these dangers is, in the long run, much more profitable than not doing so. So are we investing enough? Let’s put current investments into perspective.

On the one hand, the technology company Apple and the oil company Saudi Aramco are currently the richest companies in the world in market capitalization, with a value of around 2.5 trillion dollars; the video game industry moves close to 200 billion dollars, which is more or less the current wealth of Elon Musk, the richest person in the world; and the most expensive house in the world, the Buckingham Palace, costs about 3 billion dollars.

On the other hand, Toby Ord estimates that the global investment in reducing existential risks is of the order of 100 million dollars. In other words, humanity invests much less in preventing existential risks than in… ice cream.

The probability of any of these risks may be low. But it just takes one of them to materialize to justify the entire investment. And to make matters worse, and although it might surprise you, the probability of some of these risks is actually quite significant.

What are the biggest risks?

Existential risks can be classified as either natural or anthropogenic.

Natural risks are those that would occur even if there were no humans. Examples of these risks are meteorites, volcanoes, or stellar explosions (which, as an astrophysicist, I find fascinating, but it’s also true that they could destroy our planet!).

On the other hand, anthropogenic risks are those caused, accidentally or intentionally, by human action. Some examples are nuclear wars, or the risks of artificial intelligence and biotechnology. Climate change, although partly a natural phenomenon, is fundamentally caused by our greenhouse gas emissions. Pandemics could also be considered natural risks, since viruses and bacteria existed long before human beings. But we have made the risk of pandemics much greater than it would have been in prehistoric times.

But we will talk about these risks later in AltruPhysics. If you can’t wait, I recommend that you go ahead and read The Precipice. But, as a spoiler, I’ll tell you that the anthropogenic risks are much greater than the natural ones. And what’s more, according to Toby Ord, the next hundred years are going to be a Russian roulette for humanity.

We have already been on the edge of the precipice

The 20th century has already sent us more than one warning. One of these warnings was the Palomares incident, in Almería, which occurred on January 17, 1966, during the Cold War. That day a bomber plane that left the Turkish-Soviet border, headed back to the United States, accidentally collided with a tanker plane that was refueling it.

What makes this story especially dramatic is not the death of seven of the eleven crew members. Rather, that bomber jet was carrying four thermonuclear bombs, each one more sophisticated and 100 times more destructive than the bomb that was detonated in Hiroshima. Fortunately, none of them showed the 1.5 megatons that would have been released if their nuclear contents had been properly detonated. However, it did release a big amount of radioactive material in the area, which even today and for many years will remain uninhabitable.

Just two years later something similar happened again: Another bomber with four thermonuclear bombs crashed in Greenland. Again, it fortunately didn’t trigger a nuclear reaction. In total, the United States Department of Defense counts 32 similar incidents .

Events like this could not only have caused millions of deaths in a specific part of the world, but could have triggered a nuclear winter: a true existential catastrophe, with billions of human casualties.

Thermonuclear bomb explosion
Castle Romeo nuclear test, 1954 – United States Department of Energy.

Switching to another type of existential risk, we also know that there have been dangerous viruses that have escaped from research centers of the highest security level. And these breaches were not due to a person with very bad intentions. They simply happened by accident.

In short, we are human, capable of both wonderful and abominable things. And we are also clumsy, competitive and reckless. We don’t need to punish ourselves for being how we are, but we do have to act accordingly, which means preparing for the worst.

Why worry now?

As much as the world is progressing substantially every year, it’s still terrible in many ways. As I mentioned in another episode, every hour the equivalent of an airplane full of children crashes, due to causes that are easily preventable in most developed countries. You might be wondering: “How can we have the nerve to ignore these problems in order to prepare ourselves for possible future risks?”

But make no mistake: No one’s suggesting ignoring these problems. But we have to be consistent and know how to prioritize.

We should have started worrying about existential risks a long time ago. The longer we wait, the greater the dangers, and the less time we’ll have to face them.

So what is the probability that we will face an existential catastrophe in our lifetimes? What exactly do those existential risks entail? And what can each of us do to reduce those risks? We’ll talk about this and much more in another episode of AltruPhysics.