Essay by Eric Worrall
“We cannot air condition our way out of climate change” according to UNSW author Professor Mat Santamouris.
“We Cannot Air-Condition Our Way Out of Climate Change,” Cooling Study Finds
A new global review argues passive cooling technology must become central to climate adaptation.
Published: July 6, 2026
Original story from the University of New South Wales, SydneyAs temperatures rise around the world, air conditioning is saving lives. But a growing reliance on it is also placing unprecedented pressure on electricity grids, increasing greenhouse gas emissions and making cities even hotter.
A global review led by UNSW Sydney’s Professor Mat Santamouris AM – an expert in innovative heat mitigation technologies and strategies for cities– argues that keeping buildings cool without relying solely on air conditioning will be critical for adapting to climate change.
…
Prof. Santamouris says passive cooling should no longer be viewed as a niche architectural feature, but as essential infrastructure for a warming world.
“Air conditioning saves lives and will remain essential during extreme heat,” he says. “But we cannot air-condition our way out of climate change. If every building depends entirely on mechanical cooling, we create enormous pressure on electricity systems while adding even more heat to our cities.”
Demand for cooling is soaring
The review highlights the rapid growth in cooling demand worldwide. Global electricity consumption for cooling has reached almost 10 per cent of total electricity use, with around 10 new air conditioners sold every second. By 2050, the number of residential air-conditioning units is projected to increase to almost 5.6 billion worldwide.
…
Read more: https://www.technologynetworks.com/tn/news/we-cannot-air-condition-our-way-out-of-climate-change-cooling-study-finds-414335
The abstract of the study;
- Review Article
- Published: 02 July 2026
Passive cooling for the built environment
Nature Reviews Clean Technology (2026) Cite this article
Abstract
Passive cooling technologies reduce heat and solar gains in buildings and public spaces while dissipating excess heat. This approach could reduce impacts of mechanical air conditioning, which has environmental impacts and consumes electricity, contributing to peak demand and grid stress. In this Review, we discuss advances in passive cooling technologies, focusing on smart solar control, ventilation, and radiative, evaporative and hybrid dissipation systems. These technologies are at different stages of development and deployment, ranging from technologically mature approaches such as ventilative cooling and solar control to emerging materials for passive and radiative cooling. Each technology has benefits and trade-offs. Ventilative, radiative and evaporative cooling have low energy use, but their effectiveness is dependent on climate, timing and air quality. Solar control improves thermal comfort, requires maintenance or has design constraints. Implementation of these technologies can reduce cooling-related energy consumption and provide thermal comfort in communities where access to affordable cooling is limited. However, increasing temperatures and humidity changes could challenge their effectiveness. Policies are needed to encourage uptake of passive cooling approaches in communities that currently rely on mechanical cooling and enable uptake for those that lack cooling access.
Read more: https://www.nature.com/articles/s44359-026-00177-y
I don’t know why Professor Santamouris is so dismissive of existing efforts to adapt buildings to conditions.
Buildings have been designed to enhance comfort ever since there are buildings. Ancient buildings in the Persian Gulf were designed with primitive but surprisingly effective passive air conditioners. My grandpa explained how a building he constructed in the 1940s, he put all the insulation in the living area, so the living area would be slow to warm in the summer heat, but the bedrooms would cool quickly after nightfall.
But if an air conditioner is cheaper than retrofitting some exotic passive environmental technology, why not use the air conditioner?
If power is in short supply, just build a few more coal plants. Or nuclear plants if you are feeling all precious about CO2 emissions. Only nations and states which place impediments in the path of energy providers have to worry about electricity shortages or high prices.
Sure looked like Dr. Sanctimonious at first glance (-:
From his air-conditioned UNSW office ! 😉
UNSW stands for University of New South Wales
Wikipedia has this howler in their article on wind catcher buildings:
Doing nothing would be even cheaper.
Gee, what would make grid power unreliable and more expensive?
A quick skim of the rest of the article found nothing about effectiveness. How much do these passive systems cool, and how effective are they when the humidity is 90+%? Most of their examples were for the Mideast. I probably should have scanned the edit history to see how often such mentions were backed out by the woke elite super-editors.
‘How much do these passive systems cool, and how effective are they when the humidity is 90+%?’
And are they Energy Star compliant? I think I’ll call up a couple of the local hvac firms and see if I can get quotes for a 3-ton equivalent wind catcher.
Yes, what Frank said. The RHs in my area are often too high for efficient evaporative cooling.
Perhaps if we promise to only use air conditioning on very sunny days when there will obviously be huge amounts of free solar energy?
Completely inadequate. The only acceptable control would be to turn over the switch to the self-appointed elites, who will decide for you when/if you get to enjoy your air conditioning. Any mere citizen deciding for themselves is wholly unacceptable! Because
global warmingclimate change has NEVER been about climate change, or even the environment (remember Alinsky’s Rules for Radicals: The “issue” is never the issue), it has always been about control and wealth redistribution, thus the prosperous and successful are prohibited from behaving as if they are prosperous or successful. And that’s my rant for the day, unless I decide to issue another.China’s use of air conditioning uses more electricity than Britain’s and Germany’s total electricity use combined.
Electric powered cylinders of ‘roller-uppy’ winter loft insulation. Flick a switch, and bingo, all that trapped summer heat upstairs can escape and you get some sleep. Or just sleep in the car, petrol engine ticking over, air-con full blast. Luvverly.
Wind Turbines are catching the wind, too.
When there is wind..
And they are a cause of local warming.. as well as massive eco-damage.
Doing The Opposite: Studies Show Gigantic Wind Farms Significantly Warm The Night
Taste the lash, peasants.
erm, deplorables?
Given that wind catchers, as pictured above, could also provide convenient locations from which muezzins could call the faithful to prayer, they would appear to be the perfect low-carbon solution for many European and US cities.
/s
Well, I had a tearful laugh reading that. It’s painfully accurate.
What works in the deserts of Iran, is not going to work in the tropics, or anywhere with more than a trivial amount of moisture in the air.
In some US deserts and a few other places they were called “evaporative coolers.” They worked great when the atmosphere was dry enough and you had enough water. Not on the coast however.
One time when I was visiting Las Vegas, there was a news article about the government paying people to rip up their grass lawns and replace it with Xeriscape landscaping.
The problem is that between lawns and swamp coolers, the humidity was going up to the point that the swamp coolers weren’t working well anymore.
On a different trip, we visited Palm Springs and visited a sort of nature reserve. According to the guide, the humidity in Palm Springs had risen to the point that there was a noticeable change in the vegetation in the areas down wind of the city.
Palm Springs also went in heavily for “misting systems” over sidewalks and outdoor eating areas. More moisture downwind.
Evaporative coolers work at wet bulb temperatures up to 78F with humidity as high as 90%, but poorly. Much of the cooling requirements for coastal machinery is by once-thru seawater because it is cheaper and not affected by very high temperature and humidity conditions. Another growing cooling source is ground source heat pumps. My system in Maryland operates against a constant heat sink/source of about 55F underground via three 200 ft deep wells with u-shaped heat exchangers inserted in them. The system is much cheaper to operate than an air source heat pump and in the winter, natural gas. The downside is expensive wells.
My swamp cooler works great in 10% humidity. I can feel it falling off even at 30%.
Salute!
My swamp cooler on the shore of Great Salt Lake and humidity 40 -50% did fine. I measured one day with outside air in mid-90’s….hallway down vent was about 55 degrees! And here on Gulf coast. we have them in many florist greenhouses that keep temps comfortably in 80’s when outside in mid-90’s.
Don’t give up on them.
Remember the older buildings in the deep south with the vaulted ceilings? Hmmmmmm.
Ever see a “nautilus” attic vent? How about eave vents with a basic exhaust fan on one of them?
Gums sends..
My late 1800’s house has non mechanical features to promote cooling: tall windows to let any breezes flow through. At the top of the stairwell, is a kind of skylight with 4 vertical windows and a small, peaked roof. I can see hinges that would allow that roof to be tilted up on one side to allow the hottest air to escape, creating a stack-effect air flow. I don’t know how well it works because it has long been sealed. All skylights leak.
Not true! I grew up in Karachi, Pakistan, which is hot and humid. Air catcher buildings work well.
There is no need to engineer are way out of something that never existed in the first place.
True. However there are air catchers that in some cases work. The technology has benefits in certain applications.
There is no crisis. That does not mean we halt innovation.
So the next thing will be a green war on heating. We’ll all just have to wear more clothes in the winter since the (mandatory) heat pumps will struggle to work properly in the really cold places.
The first rule of politics in the US is don’t grab and try to pull up the third rail of voter interests. And ignorance of all the third rails is no excuse. But hey, there is this other more ancient strategy of not getting in the way of your enemies when they are talking up, marketing, and reaching for the third rail. It’s really a timing issue on when the sparks fly.
Not wanting to touch the “third rail” in politics is the primary reason why the Social Security trust fund will be empty in just a couple of years.
The unspoken political strategy is to claim credit for its rescue in the general budget or with a grocery list of multi trillion dollar stimulus items. In other words they are waiting for a known problem to unfold rather than addressing it at lower cost beforehand. They just don’t want to explain it to you until the big show opens.
If the government actually maintained the money received from Social Security taxes in the cynically named “trust fund,” they would have all the money needed to pay out the benefits.
But the “trust fund” is a mirage, it is filled with IOUs since the government spends every nickel of FICA “revenue” the instant they get their grubby hands on it.
Started with funding the Viet Nam war.
Perhaps before that, but VN certainly.
“Policies are needed to encourage uptake of passive cooling approaches in communities that currently rely on mechanical cooling and enable uptake for those that lack cooling access.”
No they are not. Policies bring laws and regulation and coercion and harassment and visits from the authorities and eventually punishment.
Get lost!
Don’t get me wrong. In 1977 as a senior engineering student I took an elective course in passive solar heating and cooling design. Fine by choice, not by force.
That is all for now.
If these devices are as cheap and effective as the advocates claim, just making the people aware of them should be all the effort that is needed.
Exactly. The only true democracy is a free supply and demand market. People vote with their dollars.
If you want to go back to the middle ages and rely on wind for energy and sun for food just go ahead and enjoy your life expectancy of 35. But go do it on an island and leave me out of it.
Well, increase the electrical generating capacity and to hell with “climate change”.
Air conditioning will not help “fight global warming”—and that is not its purpose. A fan or a washcloth soaked in cold water does not help “fight global warming” either. The risk environmentalists see in air conditioning is that it might make people forget the “climate emergency” and help them regain their cool (pun fully intended).
Air conditioning is often dismissed as a form of “technosolutionism”—how dreadful! (People used to call that progress.) The term “technosolutionism” ought to be reserved for solutions that are needlessly complex and almost entirely ineffective, or even outright harmful and contrary to the public good (wind turbines and solar panels, for example. One cannot deny that they are technological devices just as much as air conditioners or refrigerators are. Unlike the latter, however, they require enormous amounts of concrete, rely on rare metals, create dependence on China, kill birds, insects, and bats, and disfigure both terrestrial and marine landscapes.)
The problem with air conditioning is that it actually works and makes people’s lives more comfortable. But, according to these people, we are supposed to live in austerity and perpetual repentance.
Are you saying that wind and solar are a case of technononsolutionism. 😉
Absolutely! I fully embrace my reclaiming of that term to describe a technological solution that is absurdly difficult to implement, inefficient, and ultimately more harmful than useful, especially when compared with intelligent technologies such as air conditioning, which exemplify the kind of technological progress that human civilization has pursued for centuries upon centuries.
You left out EVs.
So if we can’t air-condition our way out of a climate crisis, if the planet stops warming and a new ice age starts to materialize, we should shut off all heat by stopping the use of coal and natural gas. That’s the real solution: just end fossil fuel use and all climate-associated problems will be terminated.
Correct as there will be no people left.
Do you know about zero emission technologies? Nuclear, solar, and wind?
“Global electricity consumption for cooling has reached almost 10 per cent of total electricity use, with around 10 new air conditioners sold every second. By 2050, the number of residential air-conditioning units is projected to increase to almost 5.6 billion worldwide.”
That puts the lie to the nonsense here about governments preventing the citizens from getting aircon. But having the occasional academic recommending passive cooling is not a “war on aircon”. In fact, passive cooling is a very good thing to have in conjunction with aircon. It saves money (and emissions).
So the fact that not all governments are trying to ban ACs proves that no governments are trying to ban ACs?
BTW, your academic is doing a lot more than “recommending”, he’s also demanding policies. Which always boils down into either subsidizing his preferred solution, taxing all other solutions, or mandates requiring his preferred solution, if not all three.
There are millions of academics in the world, and yes, some are pushing policies. It can happen. But it isn’t a “war”.
AC’s are clearly doing very well, and no evidence has been presented of any governments trying to ban them.
Just making them impossible to install..
… and in some cases, ordering their removal.
Mr. Stokes: Thanks for helping us skeptics avoid the alarmism of the left, which you project here so well! Lefty academics demand less AC USE, echoed in the lefty press, but it’s not “war” because AC unit sales are up. Ordinary folks defying those academics, still buying AC units and hoping to power ’em, should avoid calling this a “war” or we’ll just make the elite mad at us.
Probably not a war per se but definitely a lot of skirmishes if not battles.
People have opinions. Some like AC, some don’t. Some like SUV’s, some don’t. Some like porridge, some don’t. If your mind is set that way, you can see just about anything you do as defying someone. Another blow struck in the war on porridge.
Of course, they weren’t defying anyone. If they wanted AC, they just bought it.
In this article, perhaps. But lift your head up and look around.
England is a good place to start as is France.
Numbers provided courtesy of the UN Environmental Program.
You should check links before making a foolish comment.
I did not dispute the numbers.
And there it is. “Policies are needed”. As in governmental policies coercing people. Because Big Daddy Government knows best, right? Here’s the thing though. If passive cooling systems are so great, then they would actually save money. And maybe some do, if you don’t mind the tradeoffs. So how about Big Daddy Government keep their grubby hands off the whole business, and let people decide. Oh, but “the grid might not be able to handle it”. HAHAHAHAHAHAHAHA! And whose fault might that be? That’s right, those in Big Daddy Government trying to force unaffordable unreliable energy onto the grid, making it unstable.
Unbelievable.
Some day someone will do an analysis of the resources, natural and energy and land use, needed for each approach.
I thought the greens loved heat pumps.
Only when they are called heat pumps. If you call them air conditioners they are evil and wrong.
How terrible! Misnaming a heat pump. Just awful /s
Professor Mat Santamouris sounds like a mass murderer to me.
The trouble with getting rid of air conditioning is that the heat will come off climate change mania. A/C is the primary reason people now complain about hot days. It gives Big Climate a reason to be. Growing up in Australia we never had A/C until we moved to a mining town in the desert. But at school, at home, public transport and pretty much everywhere except cinemas, you just put up with hot days and then when you went outside you didn’t notice the heat. Get rid of A/C and the panicked howls of global boiling are reduced back to muttered curses that “it’s a bit hot today.”
I’m keeping my A/C though.
Another top education wasted on a lemming. I am all for passive temperature control for both hot and cold weather. I am totally against government mandates. I am also for heating and cooling devices for our homes and businesses. In my neck of the woods air conditioning is nice but not critical in most situations but heating is not an option we are all dead without it.
So, EVs, heat pumps, etc don’t count. What a topsy-turvy world you live in Prof. Santamouris
That’s an interesting point, if your EV has an air conditioner, does that make it good air-conditioning or bad air-conditioning?
If EV air conditioning is good because it encourages EVs, but home air conditioning is bad, does that mean you can step into the light by sitting in your EV with the aircon on while on charge during hot days rather than using a home air conditioner? Or do you have to wait until the wind starts blowing as well?
Or is EV air conditioning only there to encourage you to buy the EV, but you shouldn’t actually use it?
Hmmm, what if your EV spontaneously combusts while charging with the A/C on? Your, on fire. vehicle spews toxic fumes while your dying body leaves carbon all over the seats, because, you know, it’s carbon, that’s the issue, in it?
Just adding to the problem, Eric 😉
Can you park your EV in your living room so you can watch a movie on TV in comfort?
Hey, you just re-invented drive-ins 🙂
Yeah, but the only thing that could “catch fire” at a drive-in were the vehicular inhabitants…
Is it me?
Heat pumps (using carnot cycle) good
Air conditioning (using carnot cycle) bad