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Imagine a vast invisible network that keeps our food fresh, our drinks cold and our global economy running.
I'm talking about refrigeration or the cold chain, as the network is called.
It connects farms in Africa to supermarkets in Europe and it quietly shapes what we eat, how we live and how our planet is changing.
In this talk, food researcher Nicola Twilley explores how refrigeration transformed the world, the unexpected consequences it created and the innovative ways we can rethink freshness itself to build a better food future.
Picture Earth's icy places.
Mountain glaciers, Siberian permafrost, the poles.
This is the cryosphere, the frozen part of the world.
Now picture your fridge.
It's a white box, maybe stainless steel, maybe messy, maybe pristine, maybe full, maybe empty.
Regardless, it is just the tip of the iceberg.
Because, if you live in the developed world, your fridge is connected to an entire network of thermal control called the cold chain, and it brings nearly three-quarters of everything you eat from the farm to your table.
It's also massive.
Add all those refrigerated warehouses, shipping containers trucks, supermarket cabinets together and this artificial cryosphere is more than 700 million cubic meters.
It's a new Arctic and, unlike the real one, it's growing fast as people all around the world get their first fridge and join the cold chain themselves.
A little more than a decade ago, I realized that, even though I'd been writing about thinking about food for years, I had never set foot inside this vast artificial cryosphere we'd built for our food to live in.
So I put on my thermal underwear and set out to explore.
And what I discovered is that refrigeration isn't really about cold.
It's about freshness.
But also, once you have a fridge, every food problem seems like it can be solved by cold.
Take the avocado.
The avocado is a tropical fruit.
It has a short shelf life and it is beloved in all kinds of places where an avocado tree would never grow.
The avocado can only travel thousands of miles and remain fresh and delicious rather than shriveled and rotten because of refrigeration.
Once it's harvested, an avocado, like a human, only has a certain number of breaths it can take before it dies.
If you chill it, it breathes more slowly, and so it lives longer.
Yes, fruit and vegetables have better anti-aging tech than we do.
Right now, if you go to a supermarket in Amsterdam, the avocados on the shelf are likely from Kenya.
Kenyan production of avocados quadrupled between 2010 and 2020.
The quantity of avocado eaten by Dutch people quadrupled during roughly the same time span.
The two are not unrelated.
What's also related Avocados, with other fruits and vegetables and together with cut flowers, are now Kenya's largest source of overseas revenue.
They've overtaken coffee, tea, even tourism.
But the majority of that export produce comes from just a few large farms, several of which are owned by multinational corporations, because they are the ones that have the resources to install and maintain expensive refrigeration equipment.
Meanwhile, the avocado is thirsty.
It requires irrigation to grow in Kenya, and Kenya is currently in water crisis.
But perhaps you'd rather think about or eat a fresh marula fruit.
Well, if you're not in sub-Saharan Africa in the summer, good luck to you.
People say it tastes like a combination of pineapple, mango, lychee and guava, which sounds Amazing.
I would like to try one myself very much.
But the marula fruit doesn't show up in US supermarkets.
It doesn't refrigerate well, and so it can't be a commodity the way an avocado can.
This is another consequence of refrigeration.
Yes, the cold chain means that those of us that are connected to it can eat fresh produce all year round, but only those fruits and vegetables that can be refrigerated.
So these are just a couple of examples.
There are similar stories to be told about all perishable foods all over the globe.
But I hope you're starting to see something that should be obvious but hasn't really been part of the conversation until now, which is that refrigeration has costs as well as benefits.
We implemented mechanical refrigeration in the late 1800s to solve two very specific problems how to make lager beer in the US in summer and for real, and how to get meat to people living in the world's first truly big cities.
It has solved those problems and then some.
In countries with a US-style cold chain, people can now eat meat and tropical fruit in quantities that would have been previously unimaginable, even for royalty, and at prices that mean that almost anyone can have a burger, a bud and a banana every single day of the year.
This is miraculous, but it has trade-offs.
And the biggest trade-off of all is that cooling the artificial cryosphere is melting the natural one.
The chemicals and energy used to refrigerate food already account for between 25 and 3 percent of all global emissions.
That's just cooling food, not buildings or server farms or any of the other things we keep cool.
That's the same as maybe even a little more than global aviation.
And like I said, the cold chain is growing fast.
Developing countries want a cold chain for good reasons because it will help them make money exporting crops like avocados and because it will help them reduce food waste.
That's true, but only partially.
Refrigeration is really effective at reducing waste between the farm and the market.
Before the US had a cold chain, 30 percent of everything it grew rotted before it made it to market.
Today, those losses have shrunk almost to nothing.
But guess what?
Now Americans throw away 30 percent of everything that makes it to market.
Refrigeration moved where the waste takes place.
It didn't eliminate it.
And as for exports, that's a game you only win by competing on price, which means scale, which means a few large firms owned by multinationals.
Meanwhile, you've drained your aquifers and replaced your marula trees with avocado plantations.
Reducing food waste and lifting smallholders out of poverty are important.
Building a US-style cold chain might not be the best way to achieve them.
What's more, if we build a US-style cold chain for everyone alive today, the emissions from refrigeration will multiply by five, at which point they'll be the same size as the entire US emissions.
In other words, unimaginably huge.
OK, so that's the doom and gloom part.
This is a crisis, but it's also an opportunity, because most of that cold chain hasn't been built yet.
This is the moment to rethink our relationship with refrigeration.
And just like developing countries skipped landlines and checkbooks in favor of cell phones and digital banking, they can do better when it comes to food preservation, and then we in developing countries can learn from them to remake our own food systems.
What might this look like?
Well, for one, we can change how we refrigerate.
One example if you disturb the molecules, the atoms in particular types of materials, they will suck in heat energy from their surroundings to reorganize themselves.
Bingo, you've created a fridge.
Scientists have a super cool pun intended prototype.
It works by squeezing and releasing a cheap and common form of plastic and it produces the same amount of cooling for less than half the emissions of an old-school fridge.
So changing how we refrigerate can reduce emissions.
It is a solution.
It is not the solution.
Ultimately, we have to think about our goals.
We want our beer cold.
But For most food, the real goal is freshness.
So what if we could achieve freshness without cold?
Good news already.
You can buy fruit that has been sprayed with an edible fat-based powder that forms a nanoscale coating that keeps produce fresh at room temperature for nearly as long as the fridge keeps it in the cold.
So imagine a smallholder farmer in Africa being able to preserve their harvest using a spray bottle rather than a power-hungry fridge.
There's also a new process in commercial development that uses supercritical carbon dioxide to keep meat good at room temperature for six months plus.
Or, if you say well refrigeration, compressed geography by expanding perishable foods.
Travel time well, why not speed up travel?
Right now, America's largest grocery is delivering unrefrigerated chicken and ice cream by drone in Arkansas, taking refrigerated trucks off the street and refrigerated supermarket shelves out of the equation.
Even in the kitchen, people are working to liberate food from the fridge.
Many fruits and vegetables actually taste better, have more nutrients and last longer in slightly warmer, more humid conditions.
So why not shrink our fridges and redesign our homes to allow that?
Just to be clear, I am not anti-fridge.
I love my fridge.
Refrigeration has an important role to play in any future food system.
But let's approach it a bit more like we do cars.
These days we know we can electrify them and we can remove them from our city centers and we can replace them in some situations.
Replace them all together with bikes and better public transit.
And these can be better ways to achieve both our mobility goals and our sustainability and quality of life goals.
So let's think like that about preserving freshness using refrigeration only when it's the right solution, while also redesigning our fridges to make them more sustainable.
And maybe we can save the planet, fix our food system, and make life more delicious.
Thank you.
That was Nicola Twilley at the TED Countdown Summit in Nairobi, Kenya in 2025.
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And that's it for today.
TED Talks Daily is part of the TED Audio Collective.
This talk was fact-checked by the TED Research Team and produced and edited by our team Martha Estefanos, Oliver Friedman, Brian Green, Lucy Little and Tansika Sangmarnivong.
This episode was mixed by Christopher Faisy-Bogan.
Additional support from Emma Taubner and Daniela Balarezo.
I'm Elise Hugh.
I'll be back tomorrow with a fresh idea for your feed.
Thanks for listening.
