It wasn’t too long ago that the biggest existential threat facing humanity was nuclear war. I’ve noted before how distressingly close we’ve come to a nuclear disaster and how the threat of a nuclear holocaust is still present. However, that threat has abated in recent decades, especially as nuclear weapons have gotten so destructive that their use is somewhat redundant.

More recently, people have become more concerned about the threat posed by advanced artificial intelligence. The idea is that at some point, an AI will become so intelligent and capable that we won’t be able to stop it in the event it decides that humanity must go extinct. It’s the basis of every Terminator movie, as well as an Avengers movie.

While I certainly have my concerns about the dangers of advanced artificial intelligence, it’s not the threat that worries me most these days. We still have some measure of control over the development of AI and we’re in a good position to guide that technology down a path that won’t destroy the human race. The same cannot be said for biological weapons.

If there’s one true threat that worries me more with each passing day, it’s that. Biological weapons are one of those major threats that does not slip under the radar, as evidenced by plenty of movies, books, and TV shows. However, the extent of that threat has become more understated in recent years and has the potential to be something more powerful than nuclear weapons.

By powerful, I don’t necessarily mean deadlier. At the end of the day, nuclear weapons are still more capable of rendering the human race extinct and turning the whole planet into a radioactive wasteland. The true power of biological weapons less about how deadly they can be and more about how useful they could be to potential governments, tyrants, or extremists.

For most of human history, that power has been limited. There’s no question that disease has shaped the course of human history. Some plagues are so influential that they mark major turning points for entire continents. The same can be said for our ability to treat such diseases. However, all these diseases had one fatal flaw that kept them from wiping out the human race.

Thanks to the fundamental forces of evolution, a deadly pathogen can only be so deadly and still survive. After all, an organism’s ultimate goal isn’t to kill everything it encounters. It’s to survive and reproduce. It can’t do that if it kills a carrier too quickly. If it’s too benign, however, then the carrier’s immune system will wipe it out.

That’s why even diseases as deadly as Ebola and Influenza can only be so infectious. If they kill all their hosts, then they die with them. That’s why, much to the chagrin of creationists, evolution doesn’t favor the natural emergence of apocalyptic diseases. They can still devastate the human race, but they can’t necessarily wipe it out. It would only wipe itself out in the process and most lifeforms avoid that.

It’s also why the large-scale biological weapons programs of the 20th century could only be so effective. Even if a country manufactured enough doses of an existing disease to infect every person on the planet, it won’t necessarily be deadly enough to kill everyone. Even at its worst, smallpox and bubonic plague never killed more than two-thirds of those it infected.

That’s not even factoring in how difficult it is to distribute these pathogens to everyone without anyone noticing. It’s even harder today because powerful governments invest significant resources into preventing and containing an outbreak. If large numbers of people start getting sick and dropping dead at a rapid rate, then someone will notice and take action.

That’s why, for the most part, biological weapons are both ethically untenable and not very useful as weapons of mass destruction. They’re difficult to control, difficult to distribute, and have unpredictable effects. They also require immense resources, considerable technical know-how, and a keen understanding of science. Thankfully, these are all things that extreme religious zealots tend to lack.

For the most part, these powerful constraints have kept biological weapons from being too great a threat. However, recent advances in biotechnology could change that and it’s here where I really start to worry. With recent advances in gene-editing and the emergence of tools like CRISPR, those limitations that kept biological weapons in check may no longer be insurmountable.

While I’ve done plenty to highlight all the good that tools like CRISPR could do, I don’t deny that there are potential dangers. Like nuclear weapons, this technology is undeniably powerful and powerful technology always carries great risks. With CRISPR, the risks aren’t as overt as obvious as fiery mushroom clouds, but they can be every bit as deadly.

In theory, CRISPR makes it possible to cut and paste genetic material with the same ease as arranging scattered puzzle pieces. With right materials and tools, this technology could be used to create genetic combinations in organisms that could never occur naturally or even with artificial selection.

Imagine a strain of smallpox that was lethal 100 percent of the time and just as infectious.

Imagine a strain of the flu that was as easy to spread as the common cold, but as deadly as bubonic plague.

Imagine a strain of an entirely new pathogen that is extremely lethal and completely immune to all modern medicine.

These are all possible, albeit exceedingly difficult, with genetic editing. Unlike nuclear weapons, it doesn’t require the procurement of expensive and dangerous elements. It just needs DNA, RNA, and a lab with which to produce them. It’s a scary idea, but that’s actually not the worst of it, nor is it the one that worries me most.

A doomsday bioweapon like that might be appealing to generic super-villains, but like nuclear weapons, they’re not very strategic because they kill everyone and everything. For those with a more strategic form of blood-lust, advanced biological weapons offer advantages that sets them apart from any other weapon.

Instead of a pathogen infecting everyone it comes into contact with, what if it only infected a certain group of people that carry a specifics traits associated with a particular race or ethnic group? What if someone wanted to be even more strategic than that and craft a pathogen that attacked only one specific person?

In principle, this is possible if you can manipulate the genetics of a disease in just the right way. Granted, it’s extremely difficult, but the potential utility makes it more useful than a nuclear bomb will ever be.

Suddenly, a government or terrorist organization doesn’t need a skilled assassin on the level of James Bond to target a specific person or group. They just need the right genetic material and a working knowledge of how to program it into a synthetic pathogen. It could even be made to look like a completely different disease, which ensured it didn’t raise any red flags.

It’s not the ultimate weapon, but it’s pretty darn close. Biological weapons with this level of refinement could potentially target entire groups of people and never put the attackers at risk. As a strategy, it can effectively end an entire conflict without a shot being fired. Those infected wouldn’t even know it was fired if the pathogen were effectively distributed.

It’s one of those weapons that both terrorists and governments would be tempted to use. The most distressing part is they could use it in a way that’s difficult to detect, let alone counter. Even after all the death and destruction has been wrought, how do you even prove that it was a result of a bioweapon? Even if you could prove that, how would you know who made it?

These are the kinds of questions that only have disturbing answers. They’re also the reasons why I believe biological weapons are poised to become a far bigger issue in the coming years. Even if it’s unlikely they’ll wipe out the human race, they can still cause a special kind of destruction that’s almost impossible to counter.

Unlike any other weapon, though, the destruction could be targeted, undetectable, and unstoppable. Those who wield this technology would have the power to spread death with a level of precision and tact unprecedented in human history. While I believe that humanity will eventually be able to handle dangerous technology like artificial intelligence, I doubt it’ll ever be capable of handling a weapon like that.