Bonus: Why we should keep the cold chain as short as possible

An excerpt from my book "Living the 1.5 Degree Lifestyle"

I recently reviewed Nicola Twilley’s book Frostbite, which discussed the scale of the cold chain which delivers much of our food in North America. It is a subject I have been writing about for years, including a section of my first book, Living the 1.5 Degree Lifestyle, where I extolled the virtues of a local and seasonal diet and contradicted the conventional wisdom of the day that food miles don’t matter. Here is the relevant excerpt:

“reefer” refrigerated shipping containers;

The authors of the global food system emissions study conspicuously excluded “emissions from transportation, processing, packaging, retail, and preparation, which in total account for a minor fraction (~17%) of total food system emissions.” To me, 17% certainly doesn’t seem minor. In the footnotes, the authors reference as their source an article by Joseph Poore and Thomas Nemecek, whose work is really the foundation of the understanding of the carbon footprint of food and what I have been relying on throughout this exercise. Hannah Ritchie of Our World in Data uses their research to conclude that transportation is a minor component as well, writing:

"Eating locally would only have a significant impact if transport was responsible for a large share of food’s final carbon footprint. For most foods, this is not the case. GHG emissions from transportation make up a very small amount of the emissions from food and what you eat is far more important than where your food traveled from."

There is no argument here; what you eat is more important than where it came from. Richie also references the work of Christopher Weber and Scott Matthews and their article “Food-Miles and the Relative Climate Impacts of Food Choices in the United States,” noting that “their analysis showed that substituting less than one day per weeks’ worth of calories from beef and dairy products to chicken, fish, eggs, or a plant-based alternative reduces GHG emissions more than buying all your food from local sources.”

Gabriel Alter (on left) with engineer Mike Hand and a pile of containers behind, probably 1970

This did not sit well with me. My late dad was in transportation, and I grew up around containers and “reefers” or refrigerated trucks, and this didn’t pass the smell test. And sure enough, when I dug into the data, all Weber and Matthews measured were the food-miles, the distance the food travelled, which they converted to CO2 emissions using accepted data for different forms of transport. They do note that “there are also deviations from the average energy intensities per km used here; for example, refrigerated trucking and ocean shipping of fresh foods are more energy-intensive than the average intensity of trucking or ocean shipping.” However, they never really get into how much that is, suggesting that it doesn’t change their argument that food-miles don’t matter much, and the words “cold chain” never come up. They never did that math.

Research by sustainable design student Yu Xin Shi at Toronto Metropolitan University.

I assigned this problem to one of my students at Ryerson University, Yu Xin Shi, who found research confirming that there is much more to the cold chain than just the question of food-miles. One study reports that “overall 15% of the world’s energy production is used to power cold chains and cooling systems which still depend on fossil fuels.” Jean-Paul Rodrigue and Theo Notteboom, authors of The Geography of Transport Systems, define it as a “process since a series of tasks must be performed to prepare, store, transport, and monitor temperature-sensitive products.” It includes:

• Cooling systems to get the food down to the appropriate temperatures for processing, storage, and transportation;

• Cold storage, “Providing facilities for the storage of goods over a period of time, either waiting to be ship to a distant market, at an intermediary location for processing and distribution, and close to the market for distribution.”

• Cold transport, moving and keeping food at the right temperature and humidity;

• Cold processing and distribution, consolidating and deconsolidating loads.

The cold chain is a big operation, and it is getting bigger all the time. The authors write:

Increasing income levels are associated with a change in diet with, among others, growing demand for fresh fruit and higher value foodstuffs such as meat and fish. People with higher socioeconomic status are more likely to consume vegetables and fruit, particularly fresh, not only in higher quantities but also in greater variety. Consumers with increasing purchase power have become preoccupied with healthy eating. Therefore producers and retailers have responded with an array of exotic fresh fruits originating from around the world.

So those food-miles are in fact just a part of the bigger picture. And they might not even be accurate; according to a study on food transport refrigeration, “greenhouse gas emissions from conventional diesel engine driven vapour compression refrigeration systems commonly employed in food transport refrigeration can be as high as 40% of the greenhouse gas emissions from the vehicle’s engine.” The emissions per food-mile could be almost double.

According to the United Nations Environment Programme document Sustainable Cold Chain and Food Loss Reduction, transportation directly contributes 1.2 gigatonnes of CO2e annually from burning diesel, and is responsible for up to 7% of the world’s hydrofluorocarbon emissions because of “high refrigerant leakage and poor end-of-life disposal, contributing as much as 4% of the total GHG emissions of transporting all freight (refrigerated or not)”. HFC refrigerants have up to 22,800 times the global warming potential of carbon dioxide; surely, we want to minimize this by using less refrigerated transport.

This is why local food is back on the menu: food-miles are a poor reflection of the true impact of the cold chain. Notwithstanding the numbers from these various studies and the Our World in Data gang, I am sticking with the advice from Italian communalist Lanza del Vasto: “Find the shortest, simplest way between the earth, the hands, and the mouth.” Avoid the cold chain wherever possible, and if you can’t, keep it as short as possible.

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Still available from New Society Publishers: