This week we talk about air conditioners, pressure systems, and heat stress.

We also discuss weather memes, climate change, and dirty grids.

Recommended Book: Battle of the Linguist Mages by Scotto Moore

Transcript

An air conditioner, or AC, or maybe air con if you’re in the UK, is a device that moves heat from one location to another. In doing so, it usually dehumidifies the air, as well, so it can rapidly cool a room or entire building by shifting both heat and humidity from that room or building, elsewhere—usually outside.

This is basically the same technology used in refrigerators, a process called vapor compression allowing the device to circulate a substance called refrigerant using a compressor, a condenser, an evaporator, and an expansion valve, which—and this is a very superficial explanation of what’s happening—but these components take advantage of forced circulation and a phase-change between gas and liquid to transfer heat from the room you want to cool, or the inside of the refrigerator, and move that heat outside your building, or to the back and/or bottom of the fridge.

This is a far more active mode of air conditioning, of cooling and dehumidifying the air, than has been used throughout history. Most early methods relied on passive approaches, including but not limited to architectural elements, the use of plants and optimization of air flow, or creating basement areas for things that needed to stay cool.

Researchers have dabbled with more active methods of conditioning air for centuries, though, and several 19th century inventions served as precursors for the first iteration of modern ACs, some of which were used to create ice, which was useful unto itself, but could also be used to cool a room, if far less effectively and efficiently than an actual, holistic AC unit.

In 1894, industrial-grade ammonia compressors, powered by electricity, made this category of device suitable for urban environments; previously they just were far too bulky and difficult to power for city use. By 1896, the Hungarian engineer who came up with this new riff on the theme, István Röck, was manufacturing what he called dry air cooling apparatuses for hospitals, theaters, and other large spaces.

Just five years later, in 1901, an American inventor named Willis H Carrier developed what’s widely considered to be the first modern electrical AC unit, selling the first one to a lithography company in New York, before patenting the term air conditioning in 1906. The first residential version of this device was installed in 1914, and in 1915 the Carrier Air Conditioning Company of America was formed—a business that still exists today.

The impact of air conditioning, and this general technology category, as again, it’s also used in modern refrigeration units, cannot be overstated. This tech didn’t become widespread in the US, which is where it initially took off, in large part due to Carrier and other AC businesses’ presence in the States, until the mid-20th century, and before that, before the 1950s, the state of Florida was technically occupied, but only just barely because of its extreme heat and humidity and abundance of mosquitos. The population of Florida in 1950 was about 2.7 million, and today it’s about 23.5 million—that influx of people began after AC units became standard in buildings across the state, and the country. We’ve seen similar migrations as a result of too-hot places sudden becoming a lot more pleasant.

Similarly, refrigeration enabled a boggling amount of change within the food and beverage industry, the chemicals and industrial materials industries, and the healthcare and life science industries, because before the advent of the cold chain—the system of refrigerated spaces, including boxes and trucks and planes and ships that allowed medicines and foods and other substances to stay cold from their origin to their end-consumer—it simply wasn’t possible to sell or create or work with many of these products and materials.

The distribution of this technology is not universal or equal, however, and in some cases that inequality, that lack of access to this technology in some spaces, is the result of choice, not inaccessibility. And that’s what I’d like to talk about today: the spread, or lack thereof, of AC technologies and products, and how a recent heat wave in Europe may lead to more installations of this type of product across the continent.

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Beginning in late-May of 2026, a series of severe heatwaves engulfed Europe, and especially Western Europe, breaking all sorts of temperature records and leading to a bunch of heat-related deaths.

A recent meme gives a good sense of just how bad this heat wave has been.

Back in 2014, as part of a campaign by the World Meteorological Organization, dozens of weather presenters from around the world were invited to record fictionalized weather reports from 2050, with the intention of giving people a sense of how global climate change might impact daily life even as soon as just 36 years in the future.

One of these presenters, from France, gave a report of an imagined scenario in which a heat wave descended upon Europe, showing temperatures of 40 degrees celsius, which is about 104 degrees Fahrenheit, with some areas seeing temperatures as high as 43 C or 109.4 degrees F.

This was generally considered to be a baffling, maybe even sci-fi sort of prediction at the time. But this clip has resurfaced and widely shared, as, just 12 years later, not 36, this recent heat wave has not just met, but in some cases surpassed that imagined, too-crazy-to-be-real European heat wave scenario.

Across much of Western Europe, those temperatures milestones were hit, and in a few locations they were beat by as much as 20 degrees F.

For a few days in France, temperatures were higher than in Las Vegas, Nevada and Phoenix, Arizona, coming within 2 degrees F of temperatures in famously too-hot Death Valley, California.

All-time high temperature records were broken in Germany, and a handful of other countries are waiting to see if provisionally recorded high-temperatures they experienced hold up, to see if their own records will be broken. The UK recorded a temperature of 37.1 C (98.78 F), the Netherlands saw a top temperature of 39.4 C (nearly 103 F), Belgium hit 40 C (104 F), and Germany recorded 41.3 C (106.3 F)—all temperatures that are 5-12 C above seasonable averages, and this has led to all manner of infrastructural issues, as well.

A nuclear power plant in Switzerland had to take both reactors off the grid because the temperature of the river that cools it got too hot, a Eurostar train broke down east of Brussels with about 400 people on board, and 3 people had to be taken to the hospital. A bunch of big public events were cancelled, hospitals were filled to the point of having to triage visitors, and, if these on-the-ground issues weren’t enough, researchers in Switzerland have warned that almost all of the winter reserves built up on their glaciers are gone, which suggests the glaciers themselves will begin melting soon—something that usually doesn’t start happening until August.

This heat wave was the result of a potent heat dome, which is a pocket of high pressure that developed as a result of jet stream fluctuations that pulled hot air north, out of warmer portions of Africa. This type of high pressure pocket can then cause the heat it gathers to just sit there, unmoving, whereas typically it would be pushed around, causing it to disperse, and to thus not have such a significant impact on people and other life on the ground.

Unfortunately, these sorts of disruptions to the previous climatic norm are becoming more common as the climate shifts, due to the accumulation of CO2 and other heat-trapping gases in the atmosphere. The regulating systems we’ve evolved with are changing because there’s more overall energy, more heat, powering these systems across the planet, and that means we’re no longer able to predict them as accurately, but also that some of these systems could fundamentally change or disappear, possibly in the near future.

Events like this, which are currently rare, then, could soon become common. And meteorologists in Europe have warned, during this major heat wave, that this sort of event could be a regular thing, and soon, and could even last a lot longer; not a matter of days or weeks, but possibly spanning months at a time, without reprieve.

That’s not great news for a continent that, until now, has generally been pretty okay with its existing heat and weather infrastructure. Unlike the US and other countries that have some incredibly hot regions, leading to the widespread installation of AC units, only about 20% of homes across Europe have AC installed. As a result, as this heat wave descended on the area, trapping heat inside buildings that were constructed with cooler weather in mind, people have been unable to remain indoors, to work, to sleep; it’s been miserable. And in some cases, deadly; the combination of heat and humidity making it more difficult for peoples’ bodies to regulate heat via sweat, and that’s led to an increase in heat stress on their bodies—which is just a miserable thing to deal with, but it also means a lot of people, including but not limited to the very young and very old, are more likely to die, their bodies simply incapable of handling that level of persistent temperature strain.

Back in the summer of 2022, during another, less intense heat wave, more than 60,000 people died across Europe due to heat stress and related ailments. The numbers are still out on this more recent heat wave, but the stats are expected to be pretty grim, as in addition to the individual strain peopl...