The Tragedy of Azerbaijan Airlines Flight 8243

 

Early Christmas morning, an Embraer regional jet took off from Baku, Azerbaijan, which is on a peninsula extending from the middle of the western coast of the Caspian Sea.  It is also the capital of Azerbaijan, a small country squeezed between Iran to the south and Russia to the north.  Flight 8243 was headed to the provincial Russian capital of Grozny, and the normal route from Baku to Grozny lay along the eastern shoreline of the Caspian Sea. 

 

But things were not normal in Grozny.  In addition to heavy fog, Grozny was undergoing intermittent drone attacks as a part of the war with Ukraine.  Russian forces were deployed in the area and equipped with surface-to-air missiles.  Russian military personnel were also using electronic countermeasures that disable and falsify GPS data that airliners normally use for navigation.

 

Around half an hour into the short flight, the pilot had to switch to a more rudimentary type of guidance control than GPS due to this interference.  Shortly after getting permission to land at Grozny, something happened to make the pilot change his mind about landing there.  Passengers later reported hearing loud bangs at the time.  Thinking initially he had suffered a bird strike, the pilot reported loss of control and began asking about weather at other nearby airports.  Almost simultaneously, Russian authorities implemented a "closed-skies" order over Grozny, but Flight 8243 was already there.

 

External data indicates the plane then diverted from its intended path toward the east, ultimately flying across the Caspian Sea, which took nearly an hour.  The pilot activated an emergency signal on the plane's transponder, equivalent to a modern-day SOS, and requested an emergency landing at Aktau, Kazakhstan, on the eastern coast of the Caspian Sea.  His hydraulic systems were failing by this time, making control of the plane extremely difficult.  He managed to lower the landing gear and circled the Aktau airport in an attempt to land.  But his radio went out and the plane crashed about 3 km short of the airport, breaking into two pieces.  The nose section caught fire, but the tail section landed upside down and remained largely intact.  There were 29 survivors, including two crew members and two children, but all the survivors suffered injuries, some of them life-threatening.

 

News images of the plane showed what looked like bullet holes in the fuselage, consistent with an attack on the plane by an antiaircraft missile such as the Russian Pantsir-S1, which uses fragmentation munitions that throw shrapnel over a wide area.  On Saturday, Dec. 28, Russian president Vladimir Putin apologized for the "tragic incident" but stopped short of taking responsibility for the accident. 

 

Investigation of the crash continues, but from what we know now the sequence of events is fairly clear.  By virtue of drone attacks in its airspace, Grozny is in a war zone.  Flying into a war zone is a risky business, but at the time the Azerbaijan flight took off, there were no formal warnings extant closing Grozny's airspace.  Antiaircraft installations such as the Pantsir-S1 rely on low-frequency radar, which can give a general idea of the size of a target but nothing too specific.  If a nervous antiaircraft crew was waiting in a fog for a drone target and saw something show up on radar, it is at least understandable that they might choose to fire at it, although there are lots of good reasons not to.  That seems to be what happened .  Once the plane sustained damage to its tail section, the pilots gradually learned the extent of damage as they realized it wasn't birds, but something more serious.

 

As hydraulic fluid leaked out, they would have experienced gradual loss of control and reverted to using throttle thrust to steer the plane.  The late pilots deserve credit for making it all the way across the Caspian Sea, because ditching the plane in the water might have made it hard for anyone to survive.  As it happened, almost half the passengers and two crew members made it out alive.  For those airline travelers of us who envy first-class passengers near the front of the plane, it is some rueful comfort to note that most if not all of the survivors were in the rear half that broke off. 

 

Since the accident, several countries, including Azerbaijan, Kazakhstan, Turkistan, and Israel have banned flights into various Russian cities, citing safety concerns.  This is belated recognition that the war in Ukraine has spread through Russia in a way that no one anticipated at the start, and is yet another cost of war.

 

Other things being equal, wars are to be avoided.  But if a country is at war, what restrictions should be placed on domestic and international air travel?  Civilian deaths during wartime have been a part of war since the beginning, but the scale of air travel means that one mistake can cause hundreds of deaths.  News reports recalled the fate of Malaysian Airlines flight 17, which crashed in 2014, killing all 298 people aboard when Moscow-backed Ukranian separatists shot it down over eastern Ukraine.   

 

One searches in vain for a technological solution to such problems.  Deliberately targeting for destruction a commercial airliner of a foreign nation is a heinous act tantamount to terrorism, and it is not clear that the Azerbaijan crash resulted from a deliberate attack.  Given the circumstances of fog, it is more likely a case of mistaken identity, and Russia has launched a criminal investigation of the incident.  That may or may not throw more light on the situation. 

 

But in the meantime, it is pretty clear that anyone flying anywhere near locations in either Russia or Ukraine where missile or drone attacks have happened is taking a large chance, much larger than the usual risks of air travel, which are infinitesimal under peacetime conditions.

 

The crowning irony is that this accident happened on Christmas Day, the celebration of the birth of the Prince of Peace.  A writer named Paul Kingsnorth recently made the news by giving a speech entitled "Against Christian Civilization."  His point was that while Christ urged peace, the Western phenomenon known as Christian civilization has perfected the art of war better than any other civilization in history. 

 

We live in a fallen world, and as long as there are bad actors, good actors sometimes need to do harsh things.  And people make mistakes.  Honor goes to the pilots of Flight 8249 who saved many of their passengers under horrible conditions, and sympathy to the loved ones left behind.

 

Sources:  I referred to Associated Press articles on the crash at https://apnews.com/article/azerbaijan-airliner-crash-aktau-kazakstan-embraer-872800d95273ee96e0950192a32e5228 and https://apnews.com/article/russia-putin-plane-crash-azerbaijan-a5b0ffa3e410df53556b0cd824f32a6f, as well as the Wikipedia article "Azerbaijan Airlines Flight 8243."  Paul Kingsnorth's talk in its published form can be accessed at https://www.firstthings.com/article/2025/01/against-christian-civilization.

The Permian Basin Petroleum Museum: Oily Propaganda or Necessary Corrective?

 

On a trip to the west Texas city of Midland last week, my wife and I took in the Permian Basin Petroleum Museum.  Full disclosure requires that I let you know the following family history.  My mother's father was an oil-field-equipment manufacturer's representative, and he naturally went where people were discovering oil.  In 1929 that was the Midland-Odessa-Big Spring area, and my mother was born in Big Spring in that year.  So as I owe my existence in an indirect way to the sedimentary deposits of limestone and oil known as the Permian Basin, it's hard for me to be objective.  But I know bias when I see it, and the Museum makes no secret of where its interest lies:  to convince you of the greatness and world-girdling influence of the oil business.

 

It's easy to spot the Museum from Interstate 20:  just look for the antique wooden derrick, the tapered outline of which has become a permanent symbol of oil production, just as an envelope still symbolizes email long after most communications ceased to involve paper.  After browsing among the cable-tool rigs and working pump jacks in the open-air "oil patch," the visitor can go inside, pay twelve bucks (eight for seniors), and sit down to a fifteen-minute video entitled "Mythcrackers."  

 

This slickly-produced show purports to be a quiz program, complete with a young woman emcee whose enthusiasm is equalled by most of the contestants:  an Anglo family on the left and a Hispanic family on the right.  The contestants field questions such as "Are most gas stations owned by oil companies or OPEC?"  A tentative "Yes?" from one contestant prompts a raucous buzzer, followed by the explanation that most gas in the U. S. is sold through convenience stores, and even if an oil company's name appears on the sign, most of the outlets are owned by local franchisees.  On the screen a cartoon of your Average American Franchisee Owner shows up, with an arrow pointing to him and a big sign saying "NOT OPEC" just in case you missed the point. 

 

And it goes on from there, taking on one "myth" after another:  wind and hydroelectric power could replace oil, fracking puts lots of toxic chemicals in the ground, and so on.  Offhand, I don't recall any answer the contestants got right, unless the light eventually dawned and they started giving answers more to the petroleum industry's liking.  The way they cracked the toxic-fracking-chemical one was this:  Most of what goes into the ground is water, most of what they put in is taken out again, most of what's left is innocuous stuff like guar gum and sodium carbonate (this was accompanied by a benign-looking sketch of ice cream and cakes and other familiar products that use such chemicals), and the tiny little bit of chemicals you might not want to put on your banana sundae stay in the ground, far away from any drinking-water well formations.  There now, don't you feel better?

 

In a museum privately owned and funded by people who got exceedingly rich in an industry which truly is an essential part of modern life, to expect even-handed argumentation taking both sides of an issue into account is downright unreasonable.  These people know they are anathema in some circles, and so they're going to make things look as good as they can without outright lying. 

 

But what if you take out a fiction license and construct an entire participatory exhibit around it?  Technically, all fiction is lying, but some people—especially children—are unable to distinguish between fiction and fact.  And that's what bothered me about the second major theatrical exhibit we tried out.  It's called "The Voyage of the PetroTrekker," and the museum's website describes it thus:  "As the tactical engineers of a petroleum exploration vessel, guests journey across land, through space, and under the sea to find new sources of petroleum.  This immersive theater features interactive touch screens, dramatic lighting, and special effects to place guests at the heart of the action." 

 

The "theater" is a Star-Trek-looking circular command post, with places for you to sit and touch screens when a Captain-Kirk-like guy orders the technicians or engineers to do so.  I quickly figured out that the system didn't care if I touched anything or not, so I just watched it. 

 

Somebody spent a ton of money on this thing.  After Not-Kirk explains the mission, the screen shows something like a missile-silo lid opening with the Midland skyline in the background.  But instead of an ICBM, here comes a thing that looks for all the world like a glorified tuna can:  a gussied-up cylinder with a slightly conical top that shoots into the sky and takes off for some tropical clime where oil is suspected of being.  Not-Kirk mutters about needing to get there before some vaguely Oriental-sounding rival company beats us to it, and we see scenes of verdant greenery interlaced with rivers, just before the craft hovers and shoots down a laser beam from the sky to drill an exploratory well, and then sends down microbots that look like mechanical roaches with tails to sniff out any oil and report back to the PetroTrekker. 

 

I found myself thinking, "Wait a minute.  If I'm eight years old and don't know any better, I may go away thinking this is how we actually explore for oil, not realizing that it is really a billionaire oilman's fever dream of how he wishes he could explore for oil."  And what about those people on the ground, hey?  Did you check with them before you turned on the laser? 

 

The exit doors slid open and we emerged to see the rest of what is quite a good historical collection of petroleum-business artifacts.  But whether the PetroTrekker and Mythcrackers are really encouraging the younger generation to take up the mantle of oil exploration and production, which seems to be the purpose for which they are designed—well, let's just say I have my doubts. 

 

Sources:  The Permian Basin Petroleum Museum's website is at https://petroleummuseum.org/. 

Will TAKE IT DOWN Take It Down?

Deepfake porn, that is.  Last week, Republican Senator Ted Cruz held a news conference in which he supported passage by the U. S. House of a bill called "TAKE IT DOWN," which was passed by the Senate on Dec. 4.  Together with Democratic Senator Amy Klobuchar, he has called for the House of Representatives to pass the bill, which would provide federal criminal penalties for those responsible for putting up deepfake porn, as well as requiring the platforms that host it to take it down within 48 hours of receiving requests to do so. 

 

Several victims of deepfake porn testified about the life-shattering harm that deepfake porn causes.  Elliston Berry, who was 14 in October of 2023, woke up one morning to find that a fellow high-school student had created pornographic images with her face on them and posted them on Snapchat.  While she and her parents immediately set about trying to get Snapchat to remove the images, it took eight months and phone calls to Sen. Cruz's office to achieve that. 

 

Another tragic story involving deepfake porn was related by U. S. House representative Brandon Guffey of South Carolina.  In 2022, scammers used Instagram to contact Rep. Guffey's 17-year-old son Gavin.  The scammers pretended to be a young woman interested in nude photos of the boy.  After he complied with this request, the scammers demanded blackmail payments from him.  Tragically, Gavin committed suicide within two hours of these threats, and his father was mystified until the scammers began texting him and other relatives for cash too.  Sen. Klobuchar has counted over 20 such "sextortion" suicides between October 2021 and March of 2023.  Both she and Sen. Cruz are urging the House of Representatives to schedule an early vote on their bill before more teenagers die, according to a story in the Austin American-Statesman.

 

We hear a lot about how polarized politics is and how each party will ostracize any member who has any dealings with the other side.  Perhaps this rule doesn't apply to senators who aren't running for re-election again soon, but last week's news conference is an example that belies that rule. 

 

Death knows no political affiliation, and the unstable minds of teenagers are fertile grounds for sowing seeds of digital manipulation and criminal exploitation.  The TAKE IT DOWN act has severe criminal penalties for anyone who creates deepfake porn without the victim's consent, or uses such material for criminal purposes, including fines and imprisonment of up to 30 months for intimidating minors. 

 

What I was curious about was the penalties spelled out for the platforms which harbor such evil.  What would have happened to Snapchat, for example, if the TAKE IT DOWN act had been enacted and they still dawdled eight months before removing the deepfake porn that used Elliston Berry's image? 

 

The worst that could happen to the company is that it would be found in violation of a Federal Trade Commission (FTC) rule.  Violating FTC rules is not something as familiar to me as a speeding ticket, for instance, so I had to look it up.  The main way the FTC enforces its rules is by levying fines, and indirectly, by raising a stink with bad publicity.  Now fines to a multibillion-dollar-revenue company can easily be written off as just a cost of doing business.  Bad publicity is less easily dealt with sometimes, but its effect is uncertain and depends on what else is going on in the media universe at the time.  While the penalties for laggard companies are there, they don't impress me as being rigorous enough to ensure that deepfake porn will really be taken down inside of 48 hours once the bill is passed.

 

Nevertheless, the bill is a step in the right direction.  We are in a situation with regard to teenagers and social media that is comparable to the situation we were in around 1970 when scientific evidence was accumulating that smoking led to lung cancer, but the tobacco companies were stonewalling that the evidence was insubstantial and refused to take responsibility for the millions of additional deaths that smoking caused every year. 

 

The remarkable thing about the smoking-and-health issue was that not only did tobacco companies eventually pay big in monetary terms, but the climate of social opinion turned largely from one that favored smoking as a romantic and adult thing to do, to one that opposed smoking as both harmful to oneself and others.  And that change has persisted to this day.

 

There are hints that something similar may happen with social media's use by children and teenagers.  Schools and parents are increasingly realizing that any superficial benefits of social media are vastly outweighed by the potential and actual harms it works on the developing minds of young people.  Many schools now collect smartphones at the beginning of a school day and prohibit their use until kids leave for home.  I don't know many people who have school-age children, but the ones I know give a great deal of thought to how old a teenager should be before they get a smartphone, and none of them let children under 12 have one, as far as I know.

 

The day may come when letting someone under 18, say, use social media—at least social media as it is today—will be regarded as, well, I'm trying to think of something that everybody agrees kids shouldn't do.  Bungee-jumping over the Grand Canyon?  My point is, laws can follow public opinion as well as mold it.  If the great majority of adults raising kids in the U. S. conclude that letting social media corrupt their children's minds is simply wrong, we almost don't have to worry about the laws, because the parents will deal with it themselves.  But we need laws to keep sneaky teenagers from evading their parents' prohibitions, and the TAKE IT DOWN act will help tremendously in this regard.

 

The fate of any piece of legislation is uncertain until it's signed, but the indications are hopeful that this bill will make it into law.  It will be only one brick in the wall of protection that we need to erect to keep social media from wreaking more havoc, misery, and death upon children and teenagers.  But every brick counts.

 

Sources:  The Austin American-Statesman online edition carried a story entitled "US House Urged to Ban Deepfake Porn" on Dec. 12, 2024.  I also referred to the draft version of the bill itself at https://www.congress.gov/bill/118th-congress/senate-bill/4569/text, the story of Gavin Guffey's suicide at https://www.cnn.com/2024/01/30/us/rep-brandon-guffey-instagram-lawsuit-cec/index.html, and the Wikipedia article on Snapchat.  I previously blogged on deepfake porn at https://engineeringethicsblog.blogspot.com/2024/09/deepfake-porn-nadir-of-ai.html and https://engineeringethicsblog.blogspot.com/2024/09/deepfake-porn-rest-of-story.html.

 

Indoor Air Pollution: A Tale of Two Problems

 

Wired technology reviewer Lisa Wood Shapiro is worried that just walking across a carpet will adversely affect her health.  At least she says she's worried, because she wrote a whole column about how just walking across a carpet can cause "resuspension" and raise up detectible amounts of "PM 2.5," which are particulates under 2.5 millionths of a meter in diameter.  That's pretty small, and not anything you can see with the naked eye.  One type of technology she reviews is particulate detectors, and that's how she knows that just walking across even a nominally clean carpet kicks up all this micro-dust. 

 

Being a reporter, she dug up dirt (so to speak) on how PM 2.5 particles can affect your health.  Living in a space with air purifiers that cut down such stuff can lower one's blood pressure slightly.  And the air purifiers, especially if they use HEPA (high efficiency particulate air) filters, can also get rid of something called PFAS, an array of fluorine-containing compounds that can come in solid, liquid, or gaseous form.  PFAS has been linked to cancer and other adverse health outcomes, so anything you can do to reduce your exposure to those chemicals will, in principle, benefit your health.

 

The rest of her column describes various pricey solutions to the carpet-dust problem, such as throwing out your old throw rugs and replacing them with pure-wool ones, buying battery-powered HEPA-filter-equipped vacuum cleaners, and taking off your shoes when you come into the house.  That last one isn't pricey, but on a cold day it's not that comfortable either. 

 

Indoor air pollution caused by my carpets is not high on my worry list, but I'm older than Ms. Shapiro, and some things that don't bother me at all seem to perturb folks under 40.  Solid body soap, for instance.  The attitude I sense of the younger set toward solid body soap, the kind you have to pick up with your hands and rub under running water to get suds from, resembles the attitude I have toward the "public brush and comb" provided by 19th-century railways in public bathrooms:  "Ecch!  Somebody else has touched it!"  Hence the under-40 set's preference for liquid body soap, untouched by human hands until it touches only yours.  I don't know how many germs can make a living off of solid body soap, but maybe some can.  It's probably not the actual statistics of germ-spreading from soap as it is just the ideas involved.

 

And that may be the case for Ms. Shapiro's indoor air pollution issue.  It may be partly real, or partly trumped up to give her an excuse to review a bunch of HEPA-filter vacuum cleaners.  But all of the above issues are what a friend of mine calls "first-world problems."  That is, they arise only when the basics of your existence—what you'll eat tomorrow, where you'll sleep, what clothes you will wear—are taken care of.

 

Indoor air pollution is a real and deadly problem, but not for journalists living in Maine or Brooklyn.  The United Nations Environment Programme estimates that household air pollution worldwide led to the deaths of over three million people in 2021, including 237,000 children under five. 

 

We're not talking about PM 2.5 dust raised by walking over carpets.  We're talking wood fires built on dirt in a poorly ventilated hut, or maybe a smoky kerosene fire in an old tin can.  Cutting wood for fuel is one of the leading causes of global deforestation.  If you've ever gone camping and found yourself on the wrong side of the campfire, you know how your eyes sting and you breathe in enough smoke to cause a coughing fit sometimes.  Well, what if you have to go through that every time you want a hot meal?  That is the situation for many millions of people in Africa and other underdeveloped parts of the world.

 

Dying is a lot more serious than having your blood pressure go up a few points.  What does the UN propose as a solution for household air pollution?  They pose a range of answers, but as the answers get better, the cost increases.

 

Certain kinds of charcoal briquettes make almost no indoor air pollution, but they have to be manufactured somewhere and somebody has to pay for them.  Even better than that is an LPG cookstove (liquefied petroleum gas).  And even better than that is an electric stove, but the residence has to be wired for electricity. 

 

You will notice that each step away from the pollution problem involves increasingly complicated infrastructure:  manufacturing and distribution of charcoal, transportation and storage of LPG, or an entire electric grid powered by something or other.  The anti-fossil-fuel contingent would have the electric grid powered by renewable energy.  And yes, that would be ideal.  But in a place where there is no electric infrastructure at all, and you want to get the most power to the most people for the least money, you may end up doing what China did to bring the bulk of its population out of poverty:  build a lot of fossil-fuel-powered generating plants. 

 

I'm no systems engineer, but natural gas, which we have so much of in this country we burn it off rather than ship it somewhere, would be an ideal way for people in Africa to get rid of their wood-fired cookery and use LPG stoves instead.  LPG tankers and shipping facilities will be needed, but the current U. S. administration did its best to stop such developments, because of the simplistic reason that it involves fossil fuels.  I won't go so far as to hang the indoor-air-pollution deaths of millions of people on this decision, but the connection is clear.

 

I hope Ms. Shapiro sells some vacuum cleaners.  But even more, I hope a few million people suffering through smoky suppers get to enjoy the benefits of clean cooking, even if it does contribute to global warming.

 

Sources:  Lisa Wood Shapiro's article "Your Indoor Air's Dirty Secret is Under Your Feet" appeared in Wired at https://www.wired.com/story/your-airs-dirty-secret-is-under-your-feet/.  The UN Environment Programme has an article on indoor air pollution I referred to at https://www.unep.org/news-and-stories/story/cooking-smoke-kills-millions-every-year-heres-what-world-can-do-about#:~:text=The%20problem%3A%20much%20of%20this,climate%20change%20and%20biodiversity%20loss.

 

Can a Refrigerant Be "Natural"?

 

The other evening my wife and I went to a new ice-cream shop in town, and while I was having my usual cup of vanilla I happened to glance at a refrigerated glass-front cabinet where the employees kept decorated cakes for sale.  Way down on the lower left corner of the front was a green label that read "NATURAL [followed by a leaf symbol] Refrigerant." 

 

That got me curious.  I knew the "natural" label has great consumer appeal these days when applied to food and maybe clothing, but refrigerants?  So I did some digging and discovered that there is quite a history behind the various refrigerants that have been used since mechanical refrigeration was developed in the nineteenth century.

 

For readers who need a review of how mechanical refrigeration works, here's the brief version.  When you compress a gas, it gets hotter, and that heat comes from the work you expend in compressing it.  If you then remove the heat somehow (that's what the condenser unit does outside every air-conditioned building), and the gas is suitable for use as a refrigerant in the system designed for it, it will turn into a liquid when it's cooled down enough.  If you then send the liquid through a small opening into a place where the pressure is lower, it will evaporate back into a gas, and get a lot cooler than it was before.  That's what happens in the evaporator inside an air-conditioned building.  It's the same basic principle that makes you feel cooler when you're sweating on a hot day and a breeze comes up:  water evaporates from your skin and takes some heat with it.  Run this process around and around again with the same substance, and you have a mechanical refrigerator. 

 

All right.  When large-scale mechanical refrigeration systems operated by steam power became available in first Europe and then the U. S. in the 1880s, they used ammonia gas.  The bottled liquid we call ammonia is just a solution of pure ammonia gas (NH₃) in water.  The gas itself condenses to a liquid at atmospheric pressure at a temperature of -28 F (-33 C), but under moderate pressure it can be persuaded to condense at or above room temperature, and it carries a good amount of heat away when it re-evaporates at lower pressure. 

 

Nineteenth-century ammonia was about as natural and organic as you could get.  It was obtained mainly from the waste urine from packing houses, by distillation, and it was therefore fairly expensive.  It got a lot cheaper when the Haber-Bosch process for making it from hydrogen (obtained from natural gas) and nitrogen (obtained from air) was perfected in the early 20th century.  But leaks in refrigeration machinery were common and ammonia gas is nothing you want to get loose around customers.  So the industry sought a non-toxic, non-corrosive substitute, and along came a General Motors chemist named Thomas Midgely Jr.

 

Midgely was largely responsible for the development of leaded gasoline, which in the 1920s was viewed as vital to the efficient operation of gasoline-powered vehicles.  Fresh from this first long-term environmental disaster, Midgely devised a new chemical that used carbon, hydrogen, and fluorine to make what at the time appeared to be the ideal refrigerant, which was trade-named Freon.  It became wildly popular, but in the 1970s, just when we were phasing out Midgely's first brainchild, leaded gas, it was discovered that the original type of Freon destroyed ozone in the atmosphere, at a rate that promised to leave us unshielded from the harmful ultraviolet rays that are normally absorbed by the naturally-occurring ozone layer. 

 

Somehow, the world's engineers cooperated in 1987 to agree to the Montreal Protocol, which committed the signatories to replace ozone-destroying refrigerants with some that are less harmful to the atmosphere.  Since then, the overarching question asked about new refrigerants is whether they hurt the atmosphere, and if so, by how much?  So it turns out "natural" in the context we're talking about means "less harmful to the atmosphere," and not necessarily something that occurs only in nature.

 

For example, on a website that sells restaurant equipment, I found an article that rates many current types of refrigerant with red (Not Eco-Friendly), yellow (Somewhat Eco-Friendly) and green (Eco-Friendly) labels.  Something called R-450A has a green label, and may be what's keeping the ice-cream shop's cakes cool.  It's made of a chemical called hydrofluoroolefin (HFO), which is anything but natural in the sense that it's a highly engineered artificial compound.  But if it gets loose in the air, the nature of its chemical bonds makes it turn into a reactive acid that gloms onto something or other fairly quickly and leaves the air, never making it into the stratosphere where it could bother the ozone layer. 

 

If you want "natural" to mean "naturally occurring," there is the old standby ammonia, which is still used in large-scale industrial refrigeration where its toxicity and flammability can be kept safely under control.  Propane and isobutane, which are distilled from natural gas, can also be used as refrigerants, but they can burn and have to be used in carefully sealed systems for consumer applications.  And the bad boy of the climate-change movement itself, carbon dioxide, can also be used as a refrigerant, although it doesn't condense unless the pressure is raised to over sixty times atmospheric pressure, necessitating very sturdy compressors and containment pipes. 

 

As historian Jacques Barzun pointed out in his monumental From Dawn to Decadence, the notion that nature knows best about a wide variety of things has a life of its own, and was one reason the "natural" tribes discovered in North America were of such interest to the Europeans who eventually overwhelmed them.  In the context of refrigeration, it looks like a more accurate label than "natural" would be "eco-friendly," but the PR people know what words look good in public view, and they picked "natural." 

 

It's only pedants like me who would even think to quibble with what the word actually means.  Without rolling the cabinet out from the wall and looking at the nameplate, I couldn't tell exactly what refrigerant was being called natural.  And my curiosity has its limits—it was good ice cream, and I didn't want to cause a scene and get barred from the shop forever.  I'm just glad that once we found problems with the refrigerant that at first glance looked ideal, we changed course and developed a whole spectrum of other ones.  That's the way engineering should work, and in this case, it has.

 

Sources:  I referred to the website https://www.webstaurantstore.com/article/474/refrigerant-types.html?srsltid=AfmBOorPfBjgu4ChyoyuSMDiNc9uETNLojxoiL_gL91XRkUgPKAPtlym

for the list of eco-friendly-graded refrigerants, and to the Wikipedia articles on HFOs and Thomas Midgely Jr.