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TED Talks Daily

How the fridge changed food | Nicola Twilley

with Nicola Twilley

Published November 24, 2025
View Show Notes

About This Episode

Food researcher Nicola Twilley explains how the global cold chain underpins modern diets by keeping food fresh and enabling long-distance transport of meat and produce, while forming an enormous artificial cryosphere. Using examples such as Kenyan avocado exports and the absence of marula fruit in U.S. supermarkets, she shows how refrigeration creates both benefits and inequities, shifts where food waste occurs, and significantly contributes to global emissions. Twilley argues that as many countries are only now building their cold chains, this is a critical moment to rethink freshness, develop lower-emission refrigeration, and explore non-cold preservation methods and system-wide redesigns of how we store and move food.

Topics Covered

Climate change and agriculture Sustainability Systems thinking Food waste Food systems Refrigeration Cold chain logistics Global food trade Agricultural exports Preservation technology

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Quick Takeaways

  • The modern cold chain forms an enormous artificial cryosphere that keeps nearly three quarters of the food in developed countries fresh from farm to table.
  • Refrigeration has enabled cheap, year-round access to products like meat and tropical fruits but concentrates export power in large, capital-intensive farms and multinationals.
  • Cooling food already accounts for roughly 2.5 to 3 percent of global emissions, comparable to or exceeding global aviation, and is poised to grow significantly.
  • Refrigeration dramatically reduced loss between farm and market but has not reduced overall waste, instead shifting it to consumers who now throw away about 30 percent of purchased food.
  • Some high-value crops like avocados become global commodities because they refrigerate well, while others like marula fruit remain invisible internationally because they do not.
  • Expanding U.S.-style cold chains worldwide could multiply refrigeration emissions by five, reaching a scale comparable to total current U.S. emissions.
  • New technologies, such as solid-state fridges using squeezed plastic and edible coatings that preserve produce at room temperature, can deliver freshness with far fewer emissions.
  • Developing countries can potentially leapfrog legacy cold-chain models, adopting smarter, lower-emission preservation methods that richer countries can then emulate.
  • Rethinking refrigerators, homes, and food distribution to use cold only where it is truly needed could align freshness, sustainability, and quality of life goals.
  • Focusing on the goal of freshness rather than the tool of cold opens up a broader set of solutions, from new preservation processes to faster delivery methods like drones.

Podcast Notes

Podcast introduction and framing of the topic

Host introduces TED Talks Daily and herself

Elise Hu states that the listener is tuned into TED Talks Daily[2:36]
• She describes the show as bringing new ideas to spark curiosity every day
Elise Hu identifies herself as the host[2:45]

Framing refrigeration as an invisible global network

The host asks listeners to imagine a vast, invisible network that keeps food fresh, drinks cold, and the global economy running[2:46]
• She clarifies that she is talking about refrigeration, also known as the cold chain when considered as a network
Description of the cold chain's reach[2:56]
• Elise explains that the cold chain connects farms in Africa to supermarkets in Europe
• She notes that it quietly shapes what we eat, how we live, and how the planet is changing

Introduction of guest and talk theme

The host introduces food researcher Nicola Twilley[3:07]
• She says Twilley explores how refrigeration transformed the world and the unexpected consequences it created
• Elise adds that the talk covers innovative ways to rethink freshness to build a better food future

Natural cryosphere versus artificial cryosphere of refrigeration

Defining Earth's natural cryosphere

Nicola Twilley asks listeners to picture Earth's icy places[3:25]
• She lists mountain glaciers, Siberian permafrost, and the poles as elements of this frozen part of the world
She names this frozen part of the world the cryosphere[3:37]

Introducing the household fridge as connected to a larger system

Twilley then asks the audience to picture their fridge[3:39]
• She describes it as a white box, maybe stainless steel, maybe messy or pristine, full or empty
She says the home fridge is just the tip of the iceberg in a larger thermal network[3:58]
• She notes that if you live in the developed world, your fridge is connected to an entire network of thermal control

Defining the cold chain and its scale

Twilley states that this network is called the cold chain[4:03]
She explains that the cold chain brings nearly three quarters of everything you eat from the farm to your table[4:05]
Description of the artificial cryosphere's size[4:52]
• She lists components such as refrigerated warehouses, shipping containers, trucks, and supermarket cabinets
• Adding these together, she says this artificial cryosphere exceeds 700 million cubic meters
Comparison to a new Arctic and its growth[4:30]
• Twilley calls this artificial cryosphere a new Arctic
• She contrasts it with the real Arctic by saying the artificial one is growing fast
• She attributes this growth to people around the world getting their first fridge and joining the cold chain

Personal discovery and reframing refrigeration as about freshness

Twilley's motivation to explore the cold chain

She recalls that a little more than a decade ago she realized she had never set foot inside this vast artificial cryosphere[4:48]
• This realization came despite her having written and thought about food for years
She describes deciding to explore the cold chain[4:39]
• She humorously notes putting on thermal underwear before setting out

Refrigeration as primarily about freshness

Twilley shares her core insight that refrigeration is not really about cold but about freshness[5:04]
She observes that once you have a fridge, many food problems seem solvable with cold[5:14]

Case study: Avocados, refrigeration, and Kenyan agriculture

Biology of avocados and their dependence on refrigeration

Twilley introduces the avocado as a tropical fruit with a short shelf life[5:22]
• She notes that avocados are beloved in many places where avocado trees would never grow
She explains that avocados can travel thousands of miles and stay fresh and delicious instead of shriveled and rotten because of refrigeration[5:32]
Analogy between avocado respiration and human breathing[5:42]
• Twilley says that, once harvested, an avocado, like a human, only has a certain number of breaths it can take before it dies
• She explains that chilling the avocado slows its breathing, thereby extending its life
• She jokes that fruits and vegetables have better anti-aging technology than humans do

Kenyan avocado exports and Dutch consumption

Twilley states that avocados in a supermarket in Amsterdam are likely from Kenya[6:04]
She notes that Kenyan avocado production quadrupled between 2010 and 2020[6:05]
She adds that the quantity of avocado eaten by Dutch people quadrupled in roughly the same period[6:11]
• She explicitly says these trends are not unrelated, implying a linked supply-demand dynamic enabled by refrigeration

Economic significance of refrigerated exports for Kenya

Twilley states that avocados, together with other fruits, vegetables, and cut flowers, are now Kenya's largest source of overseas revenue[6:28]
• She says these export products have overtaken coffee, tea, and even tourism in revenue terms
She clarifies that the majority of this export produce comes from just a few large farms[6:38]
• Several of these large farms are owned by multinational corporations
• She explains that these firms have the resources to install and maintain expensive refrigeration equipment

Environmental strain: water use for avocados in Kenya

Twilley highlights that avocados are thirsty crops that require irrigation in Kenya[6:55]
She notes that Kenya is currently in a water crisis, making this water demand significant[6:59]

Contrast case: Marula fruit and limits of refrigeration-driven commodification

Describing marula fruit and its absence from global markets

Twilley asks the audience to consider the fresh marula fruit as an alternative example[7:07]
• She notes that unless you are in sub-Saharan Africa in the summer, you are unlikely to access fresh marula fruit
She relays descriptions of marula's taste as a combination of pineapple, mango, lychee, and guava[7:19]
• She comments that this flavor combination sounds amazing and that she would like to try one herself
Twilley points out that marula fruit does not appear in U.S. supermarkets[7:25]
• She explains that marula does not refrigerate well and therefore cannot be a commodity in the same way that avocados can

Selective globalization of crops based on refrigerability

Twilley generalizes that the cold chain allows those connected to it to eat fresh produce year-round[7:41]
However, she stresses that this year-round access only applies to fruits and vegetables that can be refrigerated[7:45]
• She says that this is another consequence of refrigeration, and notes that similar stories could be told about perishable foods across the globe

Refrigeration's benefits and hidden costs

Highlighting that refrigeration has both benefits and costs

Twilley says it should be obvious, but has not been part of the conversation, that refrigeration has costs as well as benefits[8:07]

Original problems refrigeration was built to solve

She states that mechanical refrigeration was implemented in the late 1800s to solve two specific problems[8:11]
• The first problem was how to make lager beer in the U.S. in summer, and she emphasizes this was a real issue
• The second problem was how to get meat to people living in the world's first truly big cities
She notes that refrigeration solved those problems and then some[8:31]

Miraculous expansion of diets enabled by cold chains

In countries with a U.S.-style cold chain, people can now eat meat and tropical fruit in previously unimaginable quantities[8:35]
• She remarks that this abundance would have been unimaginable even for royalty in the past
She adds that these foods are available at prices that allow almost anyone to have a burger, a beer, and a banana every day of the year[8:49]
Twilley calls this situation miraculous but emphasizes that it involves trade-offs[8:55]

Environmental impact and growth of refrigeration emissions

Cooling the artificial cryosphere versus melting the natural one

Twilley states that cooling the artificial cryosphere is melting the natural cryosphere[9:01]

Quantifying refrigeration's contribution to global emissions

She explains that the chemicals and energy used to refrigerate food already account for between 2.5 and 3 percent of all global emissions[9:07]
• She clarifies that this figure is just for cooling food, not for cooling buildings, server farms, or other uses
She compares this emissions share to global aviation, saying refrigeration emissions are the same as, or maybe even a little more than, aviation[9:25]

Drivers of cold chain growth in developing countries

Twilley reiterates that the cold chain is growing fast[9:27]
She explains that developing countries want a cold chain for good reasons[9:31]
• One reason is to help them make money exporting crops like avocados
• Another reason is to help reduce food waste
She notes that these perceived benefits are true, but only partially true[9:41]

Refrigeration and food waste: shifting, not eliminating, losses

Historical waste reduction between farm and market

Twilley says refrigeration is effective at reducing waste between the farm and the market[9:48]
• Before the U.S. had a cold chain, 30 percent of everything it grew rotted before reaching the market
She notes that today these pre-market losses in the U.S. have shrunk almost to nothing[9:59]

New pattern: consumer-level food waste

Twilley points out that now Americans throw away 30 percent of everything that makes it to market[10:06]
She concludes that refrigeration moved where waste occurs rather than eliminating it[10:09]

Export competition, scale, and resource trade-offs

Inequities in export-based cold chains

Twilley says that export markets are a game you only win by competing on price[10:18]
• Competing on price pushes producers toward scale, favoring a few large firms
She notes that these large firms are often owned by multinational corporations[10:25]
• Meanwhile, local environments may suffer, such as having aquifers drained and marula trees replaced by avocado plantations

Questioning whether U.S.-style cold chains achieve development goals

Twilley acknowledges that reducing food waste and lifting smallholders out of poverty are important goals[10:36]
She argues that building a U.S.-style cold chain might not be the best way to achieve those goals[10:47]

Future emissions trajectory if cold chains expand globally

Projected growth in refrigeration emissions

Twilley projects that if a U.S.-style cold chain were built for everyone alive today, refrigeration emissions would multiply by five[10:50]
She says that at that point, emissions from refrigeration would be the same size as the entire U.S. emissions[10:57]
• She characterizes that level of emissions as unimaginably huge

Crisis and opportunity to rethink food preservation

Recognizing the current moment as both doom and chance

Twilley labels the situation as a crisis but also an opportunity[11:09]
She notes that most of the global cold chain has not yet been built[11:12]
• Because of this, she argues this is the moment to rethink the relationship with refrigeration

Leapfrogging legacy systems in developing countries

She compares potential changes in food preservation to how developing countries skipped landlines and checkbooks in favor of cell phones and digital banking[11:27]
Twilley suggests that developing countries can do better than legacy models when it comes to food preservation[11:33]
• She adds that people in developed countries can then learn from these approaches to remake their own food systems

Changing how we refrigerate: lower-emission technologies

Concept of alternative refrigeration based on material properties

Twilley proposes changing how we refrigerate as one pathway[12:20]
She describes a principle where disturbing certain materials makes them suck in heat energy from their surroundings as they reorganize[11:55]
• She notes that by exploiting this property, you effectively create a fridge

Example: prototype fridge using squeezed plastic

Twilley mentions that scientists have a prototype fridge based on this effect[12:16]
• She says the prototype works by squeezing and releasing a cheap and common form of plastic
She reports that this device produces the same amount of cooling for less than half the emissions of an old-school fridge[12:15]

Limitations of technology-only solutions

Twilley notes that changing how we refrigerate can reduce emissions and is a solution[12:22]
She emphasizes that it is not the solution, suggesting technological fixes alone are insufficient[12:24]

Rethinking goals: freshness without cold

Distinguishing between cold and the goal of freshness

Twilley reiterates that while we want our beer cold, for most food the real goal is freshness[12:35]
She poses the question of whether we can achieve freshness without relying on cold[12:39]

Edible coating technology for room-temperature produce

Twilley notes that consumers can already buy fruit sprayed with an edible fat-based powder[12:47]
• She explains that this powder forms a nanoscale coating on produce
She states that this coating keeps produce fresh at room temperature for nearly as long as a fridge would keep it in the cold[12:57]
• She invites listeners to imagine a smallholder farmer in Africa using a spray bottle instead of a power-hungry fridge to preserve their harvest

Supercritical carbon dioxide for meat preservation

Twilley mentions a new process in commercial development that uses supercritical carbon dioxide[13:10]
She says this process can keep meat good at room temperature for more than six months[13:14]

Alternative strategy: speed of delivery instead of extended cold storage

Twilley notes that refrigeration compressed geography by expanding the travel time of perishable foods[13:22]
She proposes that speeding up travel could be another way to address perishability[13:22]
• She describes how America's largest grocery is delivering unrefrigerated chicken and ice cream by drone in Arkansas
• This approach removes refrigerated trucks from the street and refrigerated supermarket shelves from the equation for those deliveries

Liberating some foods from the fridge and redesigning homes

Rethinking which foods truly need refrigeration

Twilley notes that people are working in the kitchen context to liberate food from the fridge[13:47]
She explains that many fruits and vegetables actually taste better, have more nutrients, and last longer in slightly warmer, more humid conditions[13:51]

Design implications for fridges and homes

Twilley suggests shrinking our fridges and redesigning our homes to accommodate warmer, more humid storage for suitable produce[14:03]

Balanced perspective on refrigeration and analogy to cars

Affirming that refrigeration still has an important role

Twilley clarifies that she is not anti-fridge[14:09]
• She says she loves her own fridge
She insists that refrigeration has an important role in any future food system[14:15]

Using the car analogy to frame smarter refrigeration use

Twilley proposes approaching refrigeration more like society now approaches cars[14:19]
She notes that we know we can electrify cars, remove them from city centers, and replace some car trips with bikes and better public transit[14:28]
• She argues that such replacements can better achieve mobility, sustainability, and quality of life goals

Strategic use of refrigeration and redesign for sustainability

Twilley suggests thinking similarly about preserving freshness[14:43]
She calls for using refrigeration only when it is the right solution[14:47]
She also advocates redesigning fridges themselves to make them more sustainable[14:51]
She concludes with the aspiration that doing this could save the planet, fix the food system, and make life more delicious[14:58]

Outro: contextual details about the talk and podcast production

Identifying event and location of the talk

The host notes that the talk was delivered by Nicola Twilley at the TED Countdown Summit in Nairobi, Kenya in 2025[15:12]

Information about TED curation and production credits

Listeners are told they can learn more about TED's curation at TED.com slash curation guidelines[15:18]
The host states that TED Talks Daily is part of the TED Audio Collective[15:22]
She says the talk was fact-checked by the TED Research Team[15:26]
• She lists members of the production and editing team by name
• She mentions that the episode was mixed by Christopher Fasey-Bogan and supported by other staff

Host sign-off

Elise Hu says she will be back tomorrow with a fresh idea for the feed[15:44]
She thanks listeners for listening before the episode ends[15:44]

Lessons Learned

Actionable insights and wisdom you can apply to your business, career, and personal life.

1

Technologies that solve urgent problems, like refrigeration for food preservation, often create new environmental and social trade-offs, so they must be evaluated as parts of a larger system rather than in isolation.

Reflection Questions:

  • • What technologies in my life or work have I assumed are purely beneficial without examining their wider impacts?
  • • How could I map the upstream and downstream consequences of a tool or system I currently rely on?
  • • What is one technology decision I can revisit this month with a more holistic, system-level perspective?
2

Efficiency improvements can simply move waste from one part of a system to another rather than eliminating it, so real progress requires tracking outcomes across the entire value chain.

Reflection Questions:

  • • Where in my workflows or organization might apparent efficiencies be hiding waste that has just shifted location?
  • • How could I redefine success metrics so they capture the full lifecycle of a product, project, or process instead of just one stage?
  • • What is one process I can audit end-to-end this quarter to see where waste has migrated rather than disappeared?
3

Infrastructure choices, such as building capital-intensive cold chains, shape who benefits and who is excluded by favoring actors with the resources to participate at scale.

Reflection Questions:

  • • In the systems I influence, who is advantaged by the current infrastructure and who is unintentionally locked out?
  • • How might I design or advocate for solutions that small players or resource-limited participants can realistically access?
  • • What concrete step can I take this year to reduce barriers for those currently excluded from key systems or markets I depend on?
4

Leapfrogging legacy models, as seen when countries skip older technologies in favor of newer ones, can open opportunities to adopt cleaner, smarter solutions from the start.

Reflection Questions:

  • • Where am I copying legacy approaches out of habit instead of exploring newer, more suitable options?
  • • How could I use the idea of leapfrogging to redesign a system or process without being constrained by past choices?
  • • What is one area of my work or life where I could intentionally bypass an outdated solution in favor of a more future-proof alternative?
5

Focusing on the underlying goal (such as freshness) rather than the traditional means (such as cold) broadens the range of innovative solutions you can imagine and implement.

Reflection Questions:

  • • In a challenge I am facing now, what is the real goal I am trying to achieve beneath my current chosen methods?
  • • How might my options change if I temporarily forgot how people usually solve this problem and instead brainstormed from the goal backward?
  • • What is one problem this week where I can explicitly separate the desired outcome from the assumed tool and test a different approach?

Episode Summary - Notes by Dakota

How the fridge changed food | Nicola Twilley
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