Seasonality and Sustainability In an Uncertain World

Autumnal Squash
Photo by Aaron Burden on Unsplash

Seasonal Eating Is Not Old-Fashioned

In our globalised world the idea of seasonality and sustainability in the foods we can buy has, until recently, been considered old fashioned and irrelevant. Why would we want to limit ourselves when the produce of the world is available to us? Fresh strawberries in midwinter? Absolutely. Fresh brussels sprouts in June? Yes! Fresh asparagus in September? Well, why not? And of course, avocados all year round!

Now, the rising risks of climate change and an increased awareness of environmental factors, as well as concerns about food miles and a desire to support local farming are all raising the profile of seasonal eating, bringing this idea back to wider public attention. But are all these concerns really justified? What is seasonality anyway? Is eating seasonally really better? And is seasonality the same as sustainability?

What is Seasonal Eating?

The UK Department of Environment, Food and Rural Affairs (DEFRA) has two definitions for seasonal eating:

Global seasonality is about where a food is grown but not necessarily consumed. For example, apples are harvested in New Zealand in February and March and are shipped to Europe to be eaten over the spring and summer.

Local seasonality is about where a food is both grown and consumed. Apples in Europe are harvested in late summer and early autumn and are then eaten, in Europe, throughout autumn and winter.

Local seasonality sounds great, doesn’t it? It must be the most sustainable option.
Except that there is nothing simple about this.

Greenhouses Are Not Very “Green”

The UK’s northerly latitude means that variety in some seasons can be severely limited. Whilst the UK produces plenty of potatoes and cabbage in January, it doesn’t produce much in the way of green stuff or fruit. And, what there is, is grown in heated greenhouses. These have a far greater negative environmental impact than imported food which has been grown in unheated greenhouses. And, honestly, who wants to survive on brussel sprouts and potatoes alone?

Just What Is a Sustainable Diet?

But is a seasonal diet also a sustainable diet?

A sustainable diet is one that considers not just the carbon footprint of any food, but also the environmental impact of things like agrichemical use (herbicides, pesticides and fertilizers); water use; an increase in plant-based foods (but not necessarily the total exclusion of animal products such as meat, fish, eggs and dairy); how much processing a food goes through – because processing uses energy and creates pollution; and a reduction in food waste. Sustainable diets also need to be accessible, affordable, nutritionally sound, safe and healthy.

All of that from our food is a pretty tall order.

Seasonal Can Be Better Nutritionally

Local seasonal eating does have some clear advantages.
Fruit and vegetables that are in season tend to be cheaper, partially because there is a plentiful supply and partially because they do not need to be transported so far. Shorter transportation time often means a higher nutrient value, particularly vitamin C, the vitamin B complex and carotenoids, which are important antioxidant nutrients.

But eating any fruit and vegetables, seasonal or not, is beneficial to our health. Fruit and vegetable consumption in the UK is worryingly low, with nearly 90% of people in the UK eating less than three portions of fruit and vegetables a day, and over 20% eating less than one portion per day.

Milk Produced In the UK Varies With Seasons

Interestingly, it is not just fruit and vegetables that are nutritionally impacted by the seasons: levels of vitamin A and vitamin D are far lower in milk produced in autumn and winter than they are in milk produced in spring and summer. And levels of iodine in milk produced in the UK also varies by season, with milk produced in the spring having a higher level of iodine than milk produced in autumn.

Vitamins A and D and the mineral iodine are all nutrients of concern in the UK, because intake levels are far too low. So drinking spring and summer milk, or eating cheese made with spring and summer milk, could benefit the nation’s health.

Seasonal Tastes Better

Seasonal fruit and vegetables also taste better. Because they have been allowed to ripen fully, the complex flavour compounds and natural sugars in the produce have had time to develop.

Food, particularly fruit, that is transported from other countries is generally picked unripe and put into cold storage to ensure that it does not spoil during transport. Then, to make it ready to go onto the shelves in shops, it may need to be put into a heated environment in order to stimulate ripening. All of which can shorten the shelf life of imported fruits and significantly adds to the carbon footprint of imported produce.

What’s the Environmental Impact?

Although not all imported fruit and vegetables has a higher environmental impact, some, like melons and citrus fruit, and even bananas, have a lower environmental footprint than some fruits like strawberries and raspberries, which are grown in the UK.

Globally, food production accounts for 26% of all greenhouse gas emissions and, perhaps surprisingly, only about 6% of that is down to transport. Imported food also often carries the additional burden of cold storage to keep it stable during transport, and heat treatment to stimulate ripening once it has arrived at its destination.

If fruit and vegetables are imported from somewhere relatively close at hand, say Europe, in the season that they grow and ripen in, then there is no need for either cold storage (other than for transport) or heat treatment. And, if these foods have been grown in the open, or in unheated greenhouses, they may have a lower carbon footprint than foods grown in heated greenhouses in the UK.

So It’s Not As Bad As I Thought?

Although food transport accounts for only 6% of total greenhouse emissions globally, a huge percentage of that is air freight. Moving a single kilo of fruit or vegetables by air has around 100 times the greenhouse gas output as the same kilo moved by sea. If you are buying mangoes, they will have been flown into the UK. As will asparagus, green beans, sugar snap peas or berries, out of season. Citrus fruit on the other hand is likely to have come by sea because they are thick skinned and robust, which means they can withstand the time it takes.

What About Avocados (and Mangoes, and Bananas)?

Something that we don’t often think about, because it isn’t on our doorstep, is the environmental impact of imported fruit and vegetables in their country of origin. But that impact is just as significant from a sustainability perspective as the carbon footprint of getting the produce to the UK.

Mangoes have one of the largest environmental impacts of any fruit, imported or otherwise. Large amounts of pesticides are used to protect them in the growing environment and they are then further treated with pesticides before they are shipped to their destination (in cold storage and then heat treated to ripen them once they arrive)14. And mangoes are often imported from water stressed countries. So, although their water usage from irrigation is not the highest, it puts a significant strain on water availability for other things.

The global cost of avocados also goes far beyond that of transportation. Although they originated in Mexico, avocados are now widely grown around the world. And the farming of avocados to feed the global desire for them is resulting in vast deforestation, huge water usage, high agrochemical use, and the reduction in growing crops which would normally feed the local population.

As for bananas, they are the most purchased fruit in the UK and yet 1.4 million of them are thrown away by UK households every single day. Simply because of this and, without considering anything like transport costs or energy usage, they could be considered to have one of the most significant impacts on the environment.

Can I Make My Diet More Seasonal … and Sustainable?

Fruit and vegetables sold in supermarkets are labelled to show their country of origin but, if you buy from a street market, it isn’t always so easy to tell where it all comes from. A couple of good rules for trying to keep your diet seasonal are:

Try not to buy too much Mediterranean type foods like fresh tomatoes, aubergines and courgettes in the middle of winter. These will probably have been grown in heated greenhouses which take a lot of energy, and they may even have been flown into the UK.

Fresh summer berries like strawberries and raspberries in December will have been grown in heated greenhouses and are sure to have been flown into the UK. But you can buy frozen berries, which will have been picked and frozen really quickly during the summer months.

The same thing goes for things like fresh peas, asparagus and beans. Because frozen fruit and vegetables are frozen so rapidly after they have been picked, the nutrient content doesn’t have time to break down. So frozen vegetables are often more nutritious than fresh, which may have been travelling and sitting in cold storage for months, before they even get onto a supermarket shelf!

Reduce food waste. If food waste were a country, its greenhouse gas emissions would make it the third largest country in the world. Plus, wasting food is such a waste of money. Eat leftovers for lunch. Make soup – and stick it in the freezer. Once a week go through the fridge and “finish things off”.

Photo by Gabriele Lässer on Unsplash

Seasonality and Sustainability in Kent

Kent is not called “The Garden of England” without reason. More than 70% of Kent is farmland, much of which are small, family-owned farms. A lot of those small family farms are starting to work together in groups with external advisers to increase the sustainability of their farms, supporting biodiversity in wildlife, managing and increasing soil health, and, because Kent is one of the more water-stressed areas in England, in water management.

Farmers’ Markets and Box Schemes

There are dozens of farmers’ markets all over Kent, on most days of the week. Many farms also do box schemes, delivering fruit, vegetables, eggs, herbs and all sorts of other goodies – you certainly can’t get much more seasonal or sustainable than a local box scheme. And if price is a bit of an issue, fruit and vegetables sold at farmer’s markets are pretty reasonably priced, often cheaper than at a supermarket.

So, if you want to reduce your environmental footprint, and maybe save some money, it might be worth finding your local farmer’s market!