The reason why it fell out of favour isn't because it's dangerous, it's because it was ineffective outside of TV and film.
A siege of a city is more impractical than it ever has been. In ancient times a siege was conducted out of necessity; it was the only way to kill everyone inside if a population did not desire subjugation. Complete death of those resisting you was typically the goal, with the slow communication of antiquity leaving any resistance might mean coming back to an army the next time you visit. It was easier to depopulate the region and move your descendants in.
We see echoes of this in modern times. We "took" Kabul at extreme expense, but did not really "take" it as asymmetric enemy forces continued to operate throughout the entire country while the US occupied Afghanistan. Taking many cities across a nation with advanced embedded weaponry is going to be impossible. If it came down to it, such a country would resort to area denial, like Russia did in the Chechnya and Syria, leveling the cities instead of sweeping them.
We don't see people deploying chemical WMDs not because they are too expensive but because of political reasons, and after that, because they don't have them due to disarmament treaties. All it takes is someone deciding they really want to win for all of it to change. You can deny a huge area for weeks with a few chemical warheads. You can make a city inhospitable using less materiel than it'd take to flatten it.
> In static-system vs. static-system warfare. Thus, in Syria – where the Syrian Civil War has been waged as a series of starve-or-surrender urban sieges, a hallmark of static vs. static fighting – you see significant use of chemical weapons, especially as a terror tactic against besieged civilians.
The Russians being in a similar situation because they do not have equipment suitable for a highly mobile army (I don't quite expect them to use them for reasons below, but worth pointing out).
There's a lot wrong with his take. A lot of what he is writing is unsourced conjecture. It's like saying man portable missiles are irrelevant when you can have the CIA topple their government and remove their will to fight.
For one, conventional arms are horribly inefficient at killing in the first place! It's thousands of rounds fired for a confirmed kill, and the stat is equally as bad for artillery. Any marginal improvement is a big deal.
He does not convincingly separate their lack of legitimate use from moral concerns. Developed nuclear states don't use them for a lot of reasons, but a huge issue is that chemical weapons are on the escalation ladder. In the US's case it's also that we don't want to kill indiscriminately. He so much as states this at one point:
> In essence, the two big powers of the Cold War (and, as a side note, also the lesser components of the Warsaw Pact and NATO) spent the whole Cold War looking for an effective way to use chemical weapons against each other, and seem to have – by the end – concluded on the balance that there wasn’t one. Either conventional weapons get the job done, or you escalate to nuclear systems.
> But if chemical weapons can still be effective against static system armies, why don’t modern system armies (generally) use chemical weapons against them? Because they don’t need to. Experience has tended to show that static system armies are already so vulnerable to the conventional capability of top-flight modern system armies that chemical munitions offer no benefits beyond what precision-guided munitions (PGMs), rapid maneuver (something the Iraqi army showed a profound inability to cope with in both 1991 and 2003), and the tactics (down to the small unit) of the modern system do.
I take no exception to this, but basically no large army has encountered a case where they need quickly deployed area denial that is different from landmines. A massive retreat into the interior of a country may be such a case, but you run into issues where a decapitation against that state is probably going to be more effective.
For what it's worth, this is why Russia's concern of NATO countries walking up into it is nonsensical. It's just, perhaps, they never realized how nonsensical it was, as their defense planners do not have experience with a highly dynamic army. (But oddly they seem to have some idea of what might happen, as this is what likely led to their development of nuclear/neutron mortars and artillery. But any situation where those would come out is going to be ICBM time anyway.)
There's no point in detailing beyond that. Respectfully, it's like someone suggesting quicksand is a good way to stop tanks because they watched it in a cartoon. I'll add some commentary in good faith but I'm not going to comment beyond this.
The fact of the matter is that the amount of chemical product you need to try to slow down the enemy is so insanely large that it just doesn't make sense to use -- it doesn't make sense to produce, it doesn't make sense to prepare, it doesn't make sense to bother firing.
I invite you to pick your chemical weapons agent of choice (sarin, chlorine, whatever is the one), pick a spacial size you want to attack an enemy in and then do some back of the napkin estimations at how much of that chemical weapon product you would actually need in order to disperse enough in that area to achieve your objective. I don't want you to account for failed launches, or wind, temperature and so on, let's assume that every munition fired will go to the exact spot it needs to be and disperse perfectly.
You'll very quickly realise that chemical payloads are wholly useless. We're talking about in the magnitudes of hundreds or even thousands of rockets to clear out a small area.
Perhaps it made sense in trench warfare 100 years ago, but it doesn't make sense to use against a guerrilla (or even conventional) force in any modern time.
> We don't see people deploying chemical WMDs not because they are too expensive but because of political reasons, and after that, because they don't have them due to disarmament treaties. All it takes is someone deciding they really want to win for all of it to change. You can deny a huge area for weeks with a few chemical warheads. You can make a city inhospitable using less materiel than it'd take to flatten it.
None of this is true. Sorry, but it's just not. And hopefully following the exercise above you'll come to see it that way as well.
Do you have a source? Because even with all the controversy surrounding international investigation and the theories that have spawned around that, russia wasn't even a possible suspect.
That is to say: neither the Syrian government nor Russia have used chemical weapons in Syria. They haven't used them because they are -- for all intents and purposes -- useless. If you want to take down a group of people in flip flops and have access to a thermobaric[1] MLRS[2] you're not going to break international law so you can give one or two of them a scratchy throat with chlorine payloads (if you're lucky).
[0] https://wikileaks.org/opcw-douma/
To your point, some numbers from wikipedia:
The LD50 of sarin is 39 micrograms per kilogram, so 0.0039 grams to kill a 100kg man half the time in theory.
Now consider the worst of the gas attacks in Syria was in Ghouta. Fatality estimates vary considerably, but the highest estimate claims 1729 fatalities. The attack is claimed to have been performed using at least 8 rockets, likely more, each with at least 50 liters of liquid sarin. That's a lower bound of 400 liters of liquid sarin, for an upper bound of 1729 kills. Liquid sarin's density is roughly the same as water, so that works out to more than 230 grams of sarin per person killed. And if you use the lower fatality estimates or the higher rocket count estimates, the numbers are even worse.
Conclusion? The delivery/dispersion of poison gas is incredibly inefficient. In practice you need tens of thousand times more nerve gas than the LD50 figures would have you naively believe.
https://www.bellingcat.com/news/mena/2020/01/15/the-opcw-dou...
For example, that https://en.wikipedia.org/wiki/Ghouta_chemical_attack happened is not disputed by Russia; they dispute who did it.
But in any case, while yes there is a dispute around who did it... Russia was never claimed to be the responsible by anyone. The two options are either the syrian government or the rebels, and that's true for all the chemical attacks.
So the GP was completely wrong, Russia did not use chemical warfare in syria!
Their biggest target throughout their efforts? Ted Postol, professor emeritus of science at MIT, who they claimed was a Russian disinformation agent for finding the theoretical chemistry ridiculous and not practical.
Considering this, defense against them is at least mildly important. A proper defense only exists by considering offense, so they're still developing chemical weapons somewhere. The modern hot topic is viruses and other pathogens.