Martin Rowson illustration

With the world edging towards climate catastrophe, it is small wonder that many countries are once again looking at nuclear power. The reason is obvious: a plentiful source of energy with no direct CO2 emissions provides a clear route to helping the world reach its emissions targets.

It is not without serious risks, of course, as the Chernobyl and Three Mile Island meltdowns demonstrate. But to focus only on present-day dangers is to miss the larger problem, for nuclear waste remains radioactive for at least 10,000 years. And because we can’t simply banish it from this earth by blasting it into space, where it might contaminate the atmosphere, we have to store it somewhere, to be left undisturbed. That raises the question of how we tell people, ten millennia from now, where we’ve put it.

Speaking to the future is a “blind spot” for humans, says Vincent Ialenti, a cultural anthropologist at the University of Southern California and The Berggruen Institute, and author of Deep Time Reckoning: How Future Thinking Can Help Earth Now. “We have ancient brains, and are focused on shorter time spans, like 24-hour news cycles or quarterly earnings. Many of us, through social media, are even stuck in fast-paced, dopamine-modulating information echo chambers.” If this short-termism makes thinking about the future hard, then the prospect of communicating with someone 10,000 years from now likely feels far beyond our capacities.

One issue is the language we would communicate in: there’s no guarantee that English, Spanish or Mandarin will exist long into the future. “Languages evolve faster than that, or they die out,” Ialenti explains. “Try reading Beowulf in Old English. That was only written down about 1,000 years ago, in an earlier form of the same language we’re speaking now. And it’s incomprehensible.” Even more so, perhaps, think how little the word “internet” would mean even to someone living in the 1970s.

Pictures are out of the question, too. “Take a skull and crossbones,” Ialenti says, widely used to indicate poisonous substances. “In some cultural settings, that means rebirth. In others, it means death. In others, it just means pirates. So, what’s it going to mean in the future? Signage can change as fast as language. Before the Second World War, the swastika had a totally different meaning.”

We don’t know whether past civilisations tried to speak to us in the present. What we do know is that if they did, their efforts were not immediately discernable. This could either be through misunderstanding or simply a tendency to dismiss the knowledge of our ancestors, rather than embracing their wisdom. “There are oral stories about lost islands and ancient sea rises in Australia, passed down for 10,000 or so years by Aboriginal Australians, that have been corroborated by climate research,” Ialenti says. “And guess what? The colonial administrators didn’t listen.”

‘Satan’s work in England’

There are other instances, too. “Along the coast of Japan, there are centuries-old ‘tsunami stone’ slabs that read ‘High dwellings are the peace and harmony of our descendants. Remember the calamity of the great tsunamis. Do not build any homes below this point’.” Yet a nuclear plant was still built in a tsunami zone in coastal Fukushima, and these messages were only left a few hundred years ago – barely 5 per cent of the timespan a nuclear waste warning would need to last.

This poses another issue: the durability of the message itself. Weathering has made stone tablets and ceramics as little as 1,000 years old indecipherable, while the metals that are most likely to survive exposure to wind and rain, such as gold and silver, are also the ones most likely to be stolen. In the 1990s, Sandia National Laboratories – tasked with investigating safe methods of disposing of the United States’ nuclear waste – attempted to solve this problem by devising large monoliths as a warning, suggesting the US government build “menacing earthworks” or a “landscape of thorns” with concrete spikes designed to give a sense of fear and foreboding.

Yet these more abstract messages don’t always work either. “Look at Stonehenge,” Ialenti says, citing archaeologist Rosemary Joyce’s book The Future of Nuclear Waste. “In 1599, the poet Samuel Daniel described it as a ‘huge, dumb heap’. One hundred years later, Isaac Newton believed it was an antecedent of Solomon’s Temple. In the early 19th century, William Blake called it ‘Satan’s work in England’. Today, you have the UNESCO World Heritage perspective. We have to be cautious: a monument doesn’t project the same meaning throughout eternity.”

Such challenges mean that many countries have simply decided to avoid the problem of future warnings altogether. In Finland, experts concluded it could be more strategic to avoid building monuments to warn future generations about its Onkalo waste repository, due to become operational sometime in the mid-2020s. “The Finns didn’t do any of those imposing American constructions,” Ialenti says. “They plan to put their nuclear waste repository on a resource-poor islet in Western Finland, backfill it, not mark it, and try to intentionally forget about it.”

And yet, given the scale of the problem when it comes to communicating with the future, it’s small wonder the dilemma posed by nuclear waste has encouraged scholars to think outside the box – perhaps, it might be argued, a little too far outside.

Myth, ritual – and radioactive cats

In 1980, the US government assembled a panel of experts to talk to the future. Since the Second World War, nuclear waste from reactors had been amassing around the world. It was buried underground or otherwise disposed of at the bottom of the sea, presenting an invisible and deadly threat of radiation poisoning to anyone nearby.

The panel, named the Human Interference Taskforce, included an archaeologist, a psychologist, a long-term climatologist and experts in verbal and non-verbal communication. It was tasked with finding ways to warn people millennia from now of the waste, and to prevent them from accessing it. In 1984 the taskforce reported back. Their solutions were, to put it mildly, imaginative.

One of the taskforce’s most prominent members was linguist Thomas Sebeok, a specialist in non-human communication. In addition to his contributions to the official report, he also wrote an independent report in 1984, “Communication Measures To Bridge Ten Millennia”, which considered messages that had successfully survived across thousands of years, from folklore, legend and religion. He proposed keeping the uninitiated away from nuclear repositories through creating false narratives, drawing on the tools of myth and ritual. These secrets would then be entrusted to a select group of experts. “A ritual annually renewed can be foreseen,” Sebeok wrote, “with the legend retold year-by-year (with, presumably, slight variations). The actual ‘truth’ would be entrusted exclusively to – what we might call for dramatic emphasis – an ‘atomic priesthood’.”

There were major problems with the idea, Sebeok admitted: first, no culture in human history had ever attempted such a massive con as creating a fake, government-sponsored religion to scare off trespassers. It would also create a ruling class, further fragmenting human society between those with knowledge and those without. And, finally, the only examples where false narratives had been spread – such as the idea of a curse to protect Pharoah burial sites in Egypt – had either been completely ignored or served as encouragement to tomb raiders. “I can see an archaeologist being like, okay, [a curse] makes it ten times more interesting!” jokes Ialenti. “Sometimes frightening aesthetics just draw people in even more. I mean, people listen to heavy metal music all the time, right?”

Sebeok’s idea was included in a poll of alternative ways to communicate messages about nuclear waste storage, published in Zeitschrift für Semiotik (the Journal of Semiotics). Also featured were two other concepts that deserve special mention.

The first was from semioticians Françoise Bastide and Paolo Fabbri, who proposed deliberately forgetting the locations to prevent a disparity of knowledge in society. Instead, they advocated creating a biological marker to detect – and avoid – radiation. Cats, the duo argued, had been domesticated by humans for thousands of years but had no discernible purpose. Bastide and Fabbri advocated selectively breeding cats so that their skin changed colour when in contact with radiation, thereby serving as a warning to humans to leave.

“Such an animal species should dwell within the ecological niche of humans,” the duo wrote, “and its role as a detector of radiation should be anchored in cultural tradition by introducing a suitable name (for example ‘ray cat’) and suitable proverbs and myths.” Sadly, the ability to breed Geiger-counter felines does not exist.

Captain Picard's flute

The final idea of note was by Polish science fiction writer Stanisław Lem, the author of Solaris. At first, he suggested creating “information plants”, grown near atomic sites, whose DNA code could be deciphered to reveal the dangers present. But this idea was convoluted – it assumed adventurers would sequence the plants’ genetic code, or that they wouldn’t cross-fertilise and spread beyond the initial area. Lem’s second idea was far simpler: to create satellites that could orbit the Earth, transmitting stored information. In effect, he was proposing to create an external hard drive for the planet, backing up human knowledge in case of disaster, such as a nuclear war.

This idea of a “back up” is already being explored. It’s inspired science fiction, such as “The Inner Light” featured in Star Trek: The Next Generation, where a probe sent from a dying world fires an energy beam that strikes Captain Picard, transmitting to him the memories of a person’s life. Far from having ill intent, the probe is simply a message into the future, hoping that a long-destroyed culture is remembered. Through Picard, something as simple as how to play a flute was preserved.

It’s this kind of legacy that the Arch Mission Foundation, a US non-profit hoping to preserve human knowledge, is aiming to deliver. “There are a lot of risks outside of our control on our planet: nuclear threats, biological threats, pandemics and the dangers of misinformation,” explains Matthew Hoerl, the organisation’s co-founder and executive director. “But there’s no comprehensive backup for our knowledge – it all exists on flash drives, hard drives or the cloud. If something were to happen, it would be gone like that. And we feel it’s important to record our existence for the future.”

The project has already gone extra-terrestrial in its efforts to create an archive for humanity: in 2019, it sent its Lunar Library to the Moon on board an Israeli lander, with a complete copy of the English Wikipedia, photos, relics and a vault of the secrets to magician David Copperfield’s tricks, stored on optical data discs.

This doesn’t answer the most important question: how do you make sure your message survives? “There’s no guarantee it can,” Hoerl admits. “There are two issues: the message and the format. The bigger the message, the more it needs to be compressed, which makes it increasingly difficult to decode. Future beings won’t have a copy of Windows! So we’ve identified ultra-durable storage formats that are analogue, so the message can be viewed with very limited decoding. In the beginning, the message is viewable through simple magnification: even a few drops of water is enough. It includes a full Rosetta Stone of 327 languages and an instruction manual on how to build a microscope. So, as long as some language survives, we hope the message in the archive can be reconstructed in that way.”

Messages in molecules

And yet it could be another branch of science – chemistry – that already holds the answer to how humans can speak through the millennia. Scientists know that large molecules can only be formed through interaction with a biological entity; that’s how they increase their molecular complexity. If you find a molecule that’s bigger than a certain size, therefore, it’s evidence that life must have existed. Carbon dioxide, for instance, could form without life on any planet in the universe; DNA could not.

Taking this concept, Lee Cronin, a professor at the University of Glasgow, is examining whether we can use our knowledge of chemistry to leave messages for future generations that can’t exist in nature. Cronin has been working on reverse-engineering large molecules, working out how to send messages with them by chopping them up and using their constituent parts. “There will be common elements,” he says, “common parts I use again and again, like Lego bricks.” By then analysing these molecules using standard techniques, such as mass spectroscopy, predictable chemical patterns and shifts can be made to occur, allowing you to use molecules as a form of code. “You can put in different messages, using different molecules.”

This won’t help, Cronin concedes, unless you know that you are supposed to read the message. But he is also considering how humans could leave longlasting evidence of their presence – not just of life on Earth, but of an advanced civilisation. “If life on Earth is about to be extinguished, I want to leave a warning sign on Earth for aliens,” Cronin says. “So, what could you do [with chemistry]? Well, what about leaving a molecule in the atmosphere, something that says ‘We were here’? You could take every element on the periodic table that forms a bond, and make a molecule out of it. Carbon, phosphorus, silicon, whatever, just daisy chain them together! You’d then have a huge macro-molecule, and the assurance that its discoverer will know that there’s no way that it was naturally occurring.”

If this sounds outlandish, scientists are already capable of detecting just such a molecule on exoplanets thousands of light years away by using near-infrared telescopes. And once his “beacon” molecule has attracted attention, Cronin says, increasingly complex molecules next to it could be used to create and explain a cypher. “Essentially you could have molecules as decryption devices,” he says. “You could write a relatively short chemical message, maybe a few thousand words, that would be visible from space using an infrared telescope.” With today’s technology, then, we could write a greeting in our atmosphere visible across the galaxy. The downside, however, is that such a message would take thousands of years to reach other stars.

We do not have a thousand years to solve this challenge. The advent of nuclear war and the pressing dangers of climate change mean that our civilisation is under greater threat than ever. If we survive, the least we can do is ensure that future generations don’t make our mistakes. But some remain pessimistic at the chances of this happening. “Human societies do not have the skills to communicate long term,” Ialenti concludes. “We still need to cultivate within ourselves a greater societal time-literacy, and that could take generations.” Until then, all we can do is try our best and hope someone, thousands of years from now, is listening.

This piece is from the New Humanist spring 2022 edition. Subscribe here.