The world is getting hotter
Oppressive heat now stretching coast to coast
In Canada, the US, Cyprus, India, Iraq and Kuwait...
...have seen scorching temperatures in the past week
But though the dangers of rising temperatures are well documented...
...less is known about the knock-on effects of keeping cool
Air conditioning is one of the worst consumers of electricity
It heats up the planet
At least 7% of greenhouse gas emissions come from cooling...
...and with temperatures likely to soar, this is only going to get worse
The more the Earth warms...
...the more people need air conditioners...
...but the more of those we have, the warmer the world will be
Cooling saves lives and facilitates education...
...and economic growth in the world’s hottest countries...
It also brings huge environmental risks
So how can we keep cool without warming the planet?
Yes, quiet is the word for this new 1954 RCA air conditioner
Air conditioning and refrigeration systems changed the world
They fuelled economic expansion...
...transformed how food and medicines are stored and transported...
...and helped save thousands of lives
But in doing so, they’ve become a major contributor to global warming
Air conditioners are bad for the environment in a couple of ways
Together with electric fans...
...they already account for around 20% of the total...
...electricity used in buildings
America is one of the biggest culprits
The electricity it uses for air conditioning is equivalent to the total...
...electricity consumption of the continent of Africa
The problem with air conditioners guzzling so much electricity...
...is that much of the world’s power grids are still fired up...
...by fossil fuels like coal, and so it contributes to the...
...greenhouse-gas problem in a very big way
What’s more, most air conditioners and fridges use man-made gases...
...such as hydrofluorocarbons or HFCs, as a cooling medium
These gases have a tendency to leak into the atmosphere...
...where they are thousands of times more potent at trapping heat...
...than carbon dioxide
And demand for air conditioning is still rising
A big reason is urbanisation...
...as populations around the world come out of poverty and into modest...
...or middle-class lives
One of the first things people want to buy is an air conditioner
Currently, there are some 2bn AC units in use around the world...
...most across just a handful of countries
But in the tropics...
...over 90% of the 3bn or so people...
...who live there have yet to buy an AC unit
As temperatures and wages rise, demand for AC is predicted to skyrocket
By 2050 around two-thirds of the world’s households could have air conditioning...
...which means without policy intervention...
...emissions are projected to rise by 90% above 2017 levels by the year 2050
We have to find a better way, a more energy-efficient and climate-friendly way...
...of cooling the Earth’s population, or else this is going to be real trouble in future
The race is on to solve the cooling conundrum
With innovative new methods being trialled...
...from technology to make air conditioners more efficient...
...to completely eradicating the need for HFCs at all
One company developing a radical new method for cooling...
...is a Stanford University spin-out called SkyCool
So today we’re on a roof at a supermarket...
...and we’re deploying SkyCool technology...
...with their refrigeration system
So our technology works by using the sky itself as a heatsink...
...and so whether it’s sunny out or not, day or night...
...the sky is very cold...
...and what our technology is able to do is use that cold upper atmosphere...
...to cool things on the surface of the Earth with no input electricity
And so by orienting these panels towards the sky...
...they’re able to send out more heat than they take in from our atmosphere
Sounds, well, pretty cool, but SkyCool, so far...
...has only been installed in a handful of places, despite having plans for more
Innovation is fantastic, but as with the latest iPhone...
...the poorest people in the world are not likely to get the latest kit
They’ll be the least able to buy those efficient, innovative models...
...that are now coming out
Nascent technology like this can’t be relied upon alone...
...to provide affordable cooling on a mass scale
More solutions are necessary
So there’s a lot to be said for reducing demand for mechanical...
...cooling in the first place through improved buildings...
...better urban design and nature-based approaches
Designing buildings so they don’t need air conditioning...
...may be part of the answer
After all, that’s how it was done before AC was invented
Pre-World War II buildings were designed to be passively cooled
They had windows that opened
They looked at ventilation and how it moved through the building...
...and our standards of comfort were a little different
Between 1946 and 1955 nearly 1.5m homes were constructed...
...every year in America
This building boom brought about cooling complications
Post-World War II we see this explosion in the use of...
...air conditioning in buildings
The race for skyscrapers takes over
Who can be the tallest?
Who can be the biggest?
It becomes a competition
We can’t open the windows at those higher heights...
...so now these hermetically sealed buildings require...
...even more cooling load
But today, innovative building design is providing solutions...
...to keep buildings cool without relying on air conditioning
This floating office in Rotterdam, which houses the Global Centre on Adaptation...
...is a green architect’s dream
It’s powered off-grid, heated by solar panels, cooled by the river beneath it...
...and made mostly from wood
So let’s go inside and I’ll show you how it works
So here we are, actually inside the floating foundation of the floating office...
...and what we see here is actually all the technology...
...that we use to cool the building
We use the concrete of the barges and we do that by pumping...
...cooling liquid through pipes that are in the concrete
The ceiling is a cooling ceiling...
...so through the ceiling, actually there is the same pipes...
...that are also going through the concrete
So the water is actually in these pipes actually cooled by the concrete...
...and then it’s actually being pumped through the ceilings
The Global Center on Adaptation is the largest...
...floating office in the world...
...but although its exact cost isn’t known
...it’s rumoured to have been expensive to build
And with Rotterdam’s average summer temperature...
...only around 18°C, some might argue that keeping a building cool...
...in this climate isn’t hard
Projects like the Global Centre on Adaptation are impressive...
...and they’re great that they exist...
...if only for their stand-out technology and their beautiful design
But what we need are scalable, deployable solutions that are affordable...
...that we can do everywhere
In Cairo, Egypt, where temperatures regularly surpass 35°C...
...the need for scalable and sustainable cooling systems...
...has never been more urgent
The heat stress that we are facing is a real wake-up call
Sarah El Battouty and her company ECOnsult...
...were recently awarded funding from Ashden...
...a climate-solutions charity, for their innovative cooling designs
So you can imagine how much material we now have
She takes inspiration from traditional cooling techniques...
...that have been used by communities for centuries
If you go to desert communities or communities in rural Cairo...
...you’re astonished by the level of cooling...
...and they do it by knowing exactly the correct ratios...
...to build how thick the walls are
Incorporating some of these age-old techniques in the design of new buildings...
...can drastically reduce the need for air conditioning
In order to avoid heat, you don’t go in from desert-to-door immediately
You walk in, into an entry way that is very dark and it’s cooler than the desert
And then the difference is three to four degrees before you enter a room inside
From a building’s orientation to the use of local stone that stays cool...
...drawing on local knowledge could help more communities...
...find sustainable and scalable alternatives to air conditioning
4,500 miles south in Cape Town, South Africa...
...cheap adaptations to existing buildings can also reduce the need for AC
In one community, roofs made of corrugated iron...
...heat up like an oven during the summer months, so they’ve painted them white
The same way that on a hot day, you might wear a hat or on a hot day...
...you might wear white to reflect heat...
...our buildings can kind of do the same thing...
...just by putting out a white reflective coating on these roofs
We can reflect most of that heat and what it does is it...
...will not only cool the building down...
...but cool the neighbours around it down as well
That’s because white roofs can reflect sunlight better...
...meaning the roof itself can stay about 30°C cooler...
...making the internal temperature 2 to 5°C less...
...than a building with a roof painted another colour, like grey
Green buildings cannot be high-end because extreme heat doesn’t only affect...
...people on the high end...
...it affects everybody in various different ways
So there needs to be a building that caters to this kind of solution...
...for all income stratas.
While cheap improvements to walls, roofs and windows could reduce the energy...
...needed for cooling...
Small-scale initiatives don’t go far enough
Far-reaching policies and the large-scale ambition to implement them...
...are what’s needed to bring about change
Some governments are responding to the challenge
Eleni Myrivili was appointed Europe’s first chief heat officer for Athens in 2021
Her job is to come up with sustainable cooling solutions for all of the city
This summer was an extraordinary summer in the sense...
...that it started with a heatwave in June
We had these wildfires taking place at the same time...
...so not only was it difficult to breathe...
...the skies were dark, clouds were grey and red
It felt like a post-apocalyptic scene from a movie
Like many cities, Athens suffers from the urban heat-island effect...
...due to trees and plants being replaced with asphalt and concrete...
...which absorb and then release heat into the air
Here, the average annual land-surface temperatures of urban areas can get up to 3.8°C...
...hotter than non-urban areas at midday
Eleni is trying to mitigate this by turning some of the city’s streets...
...into pedestrianised tree-lined corridors
So when this is changed and it becomes a pedestrian green corridor...
...somebody walking down the street will have a different experience...
...much more thermal comfort, as we say, because it’s actually going...
...to feel up to two or two and a half degrees cooler than the rest of the city
Eleni’s team plan to create three green corridors...
...across Athens over the next two years...
...and she plans to make the most of the cooling greenery that’s already there
We’ve been focusing on supporting the existing green areas that we have...
...the existing urban forest parks and the hills...
...supporting the trees and making sure that...
...we have more of them and actually replenish the nature that we already have
Multiple studies have shown that increasing green areas in cities is crucial...
...to reduce temperatures and the need for air conditioning
If we can create more efficient ways of cooling we’ll be able to bring down...
...emissions linked to buildings, as well as those from air conditioners
The work that Athens is doing in thinking about cooling the city is very powerful...
...and needs to be replicated in other places
The urban heat-island effect is a serious phenomenon...
...and it’s only going to get worse...
...and it’s most likely to affect disadvantaged communities the most
A number of cities are making adaptations like Athens
Paris plans to have 50% of the city covered by planted areas by 2030
Medellín in Colombia has already won awards for its green corridors
And Ahmedabad in India has been acknowledged for its heat action plan...
...the first of its kind in South Asia
We have to think of solutions that are sustainable and that are resilient...
...and this means that we have to think of cooling the whole city...
...so that the building is cooler, so that we don’t need so much heating and cooling...
...by using fossil-fuel-dependent appliances
And this is extremely important because if we continue like this...
...again, we’re going to see just higher temperatures and higher temperatures...
...and more crazy climate phenomena
To implement the city-wide and ultimately country-wide solutions...
...needed to cool the planet sustainably...
...will require co-operation on an unprecedented scale
This is going to require industry, government, finance and civil society...
...to work together
We both have to deploy the most efficient technologies existing...
...as well as invent new technologies so that we have an opportunity...
...for the developing world to leapfrog ahead to a cooler and brighter future
I’m Vijay Vaitheeswaran...
...The Economist’s global energy and climate innovation editor
To keep up to date with all our climate-change coverage...
...please click on the link
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