Editor's Note: (Paul Hockenos is a Berlin-based writer focusing on renewable energy in Europe. He is the author of four books on European issues, most recently "Berlin Calling: A Story of Anarchy, Music, the Wall and the Birth of the New Berlin." The opinions in this article are those of the author. View more opinion on CNN.)
(CNN) American friends visiting my downtown Berlin apartment at the height of summer always guffaw at my rinky-dink plastic fan, propped up on a bookshelf above my desk.
Inevitably, they go on to moan about the stuffy, sweaty restaurants and night clubs that go without air conditioning as if it had never been invented.
For their part, Europeans had, until recently, done their own grousing about Americans' infatuation with AC: so wasteful in its high energy usage, unhealthy with the frosty temperatures in mid-summer and annoying given the incessant buzz of the window units!
Air con was seen as yet another luxury item of an everything-all-the-time population that insisted on a constant temperature year-round -- and gave no thought to its environmental implications.
But the planet's recent record-breaking heat waves -- and the desperate urge to stay cool -- has Europeans in particular, rethinking their prejudices and shelling out for indoor cooling systems.
In Europe, according to one industry estimate, just 20% of homes have AC units. In the United Kingdom, which this week suffered through its highest recorded temperature, it's less than 5%. In Germany, it's only about 3%. That's compared to 90% in the US.
There's been a wild run on America's luxurious eyesore this summer, which in 100-degree-plus weather is no longer considered a luxury. Indeed since 2000, when temperatures began to spike noticeably, the numbers of homes and businesses opting for AC has risen steadily worldwide.
This year's sweltering temperatures have seen AC purchases skyrocket in France and the UK, according to the climate data firm Kayrros. The trend is unmistakable: two-thirds of the world's households could have an air conditioner by 2050.
Europeans' -- and indeed the world's -- embrace of AC, however, is relevant far beyond the humble pie they appear to be digesting without a burp.
As temperatures climb inexorably upward, which science attests they will until greenhouse gas emissions are curbed, the world finds itself in an ostensibly inextricable bind -- called the vicious circle of air conditioning.
Namely, AC is an extremely energy-intensive means of cooling space. According to a World Bank report from 2019, cooling tech such as refrigerators, air conditioners, and other devices chalk up as much as 10% of all global greenhouse gas emissions. This is more than double the footprint of aviation and maritime together! At this rate, cooling emissions could double by 2030 and triple by 2100, added the report.
When the mercury has shot up this year, energy demand from cooling of all kinds, including fans, went through the roof -- thus so will emissions. Last year's record hot summer was one factor -- among others, including post-Covid-19 lockdown recovery -- in the European Union's 6.3% jump in emissions over 2020, according to the European Commission.
In other words, the hotter the planet gets, the greater the need -- in many places in Asia and the Middle East, and parts of the US and Europe, an existential need -- for cooling.
But when that power supply relies on fossil fuels, carbon emissions spike -- and at just the time when they need to decline, if we want to stop temperatures from rising in excess of 1.5 degrees Celsius (which the most recent Intergovernmental Panel on Climate Change report attests is still possible.)
The higher carbon emissions -- and temperatures -- rise, the more cooling we will need. This is the vicious circle, presumably an iron logic that condemns us all to ever more unbearable summers.
Yet, this scenario is no fait accompli and the means to break the vicious circle already lie in our hands.
Europe, out in front developing sustainable solutions to our planet's ongoing climate breakdown, has already begun implementing the technology and strategies to keep cool without making everything even hotter. The hitch: most of this innovation involves changing habits.
The first and most obvious route is the expanded use of renewable energy. An AC unit that relies on solar panels bolted to the roof or perched in the side yard has no carbon footprint to run.
An average AC system runs on the same electricity as a dishwasher, though the high energy use requires far more capacity from a solar set-up.
The good news: National energy systems using large quantities of clean power -- be that wind, solar, hydroelectric or another source -- inevitably experience smaller spikes in emissions.
Of course, the European Union is already building out zero-footprint energy at an astounding rate, as part of its "Green Deal." The share of clean energy doubled between 2004 and 2020, and the European Commission wants to double that again by 2030.
With solar and wind prices now cost competitive -- and fossil fuel prices soaring as a result of the war in Ukraine -- clean energy make economic sense on an entirely new scale.
In Europe, wind and solar parks produce a kilowatt of electricity at a fraction the cost of gas and coal. Thus the switch to renewables -- for cooling as well as everything else -- is also a money saver.
The drawback is that the clean energy rollout won't lessen emissions significantly overnight: the real impact will manifest itself in the medium and long-term when whole energy systems rely largely or exclusively on renewables. And that will take years, and in some cases, decades.
A quicker fix: affordable, energy-efficient air cooling units are a no-brainer, according to the International Energy Agency (IEA). A switch to high-performance AC units could slash cooling energy demand in half, it added. More than 80 countries already have minimum energy performance standards for air conditioners written into law -- which locks in energy savings for the entire market.
Moreover, passive cooling strategies, long the norm in the Mediterranean and other places accustomed to scorching heat, entail natural ventilation and shading: opening windows at night and lowering the blinds in mid-morning. According to one study, passive cooling could reduce air conditioning energy demand by 70%.
But there are other sustainable options, too. Geothermal cooling, smart architecture and solar thermal cooling systems can all be part of an overarching solution to global warming. More efficient buildings, designed with state-of-the-art insulation, increased air flow, and cool roofs, cut down significantly the need for mechanical cooling.
Americans could learn a thing or two from the rest of the world when it comes to habits -- since the vicious circle is nowhere more damning in those countries with the most units: China, US and Japan.
It is self-indulgent to insist on chilly temperatures in the middle of summer and rooms at t-shirt warmth in winter. The donning of sweaters indoors when it's cold outside, not because the AC is cranked up so high, is surely a habit one can adapt to.
Right now, conservation is the order of the day: to save our planet and deny Russian President Vladimir Putin his energy stranglehold of Europe.