The carbon footprint of importing food could be up to 7.5x higher than previously thought: what this means for CEA.
Carbon footprint of importing food could be 7.5x higher than thought
A new study in Nature Food has found that food’s transport emissions, once thought to be a negligibly small proportion of food systems emissions, are much higher than previously estimated - and that the carbon footprint estimates of imported fruits and vegetables will be particularly impacted.
If you work in the controlled environment agriculture (CEA) sector, this is a very important piece of research to be aware of. However, we know that everyone is feeling a little bit stretched right now, with the impacts of the energy crisis already being felt across the industry and harvest season for seasonal greenhouse growers in full swing. So to save you getting bogged down in the details, we had our Food Systems Researcher, India Langley, summarise the study and its CEA implications for you.
What are the research findings?
The report estimates that emissions from global food-miles are about 3 Gigatonnes of CO2 equivalent. This is 3.5 to 7.5 times higher than previously thought.
The new higher figure equates to nearly 30% of food-system emissions, or 19% of total food-system emissions if you also include emissions associated with land-use change (which we think you should include!). The proportion is much higher than for other non-food commodities, where freight accounts for only around 7% of emissions.
When it comes to transport emissions, how the food is transported is crucial; so it’s not quite as simple as distance travelled. Airfreighting has the highest intensity, followed by road transport, with shipping having the lowest impact. The temperature matters too. Temperature-controlled transportation releases more than three times the amount of CO2 equivalent than ambient transport. Fruits and vegetables were singled out in the study as typically needing temperature controlled transportation, often internationally. Because of this, their food-mile emissions are higher than foods transported at ambient temperatures. The study highlighted that vegetable and fruit consumption makes up over a third of global food-miles emissions. This new significantly higher estimate of their transport emissions is nearly twice what is emitted during their production - though it should be noted that production emissions for fruits and vegetables are relatively low compared to other foods. The highest carbon emissions in the study were still attributed to beef.
A hypothetical scenario where food imports were completely replaced with domestic supply was modelled in the study. While an intervention like this would be impossible in a real world setting, the model provided useful insights. A wholly domestic food consumption scenario would reduce food-miles emissions by 0.27 Gigatonnes of CO2 equivalent and food production emissions by 0.11 Gigatonnes of CO2 equivalent. Unsurprisingly, affluent counties have the highest global food transport emissions. Just by containing food chains within high-income countries, the model found it would reduce transport emissions by 0.24 Gigatonnes of CO2 equivalent and production emissions by 0.39 Gigatonnes of CO2 equivalent.
A summary of recommendations
What do these new findings mean and what are the recommendations from the authors? This more detailed accounting of food’s transport emissions asks rich nations to reconsider the trade-off between localised food versus international food trade.
More locally produced plants
The study concludes with a recommendation that to address food system emissions, we must increase domestic food production in high-income countries and combine this with the current suggested strategy of reducing the consumption of animal products in favour of a more plant-oriented diet. Both the study and Nature’s recent press about it stress that this does not mean we should reduce the amount of fruits and vegetables consumed.
Investing in peri-urban agriculture
The study highlights that a strategy that both supports a more plant-oriented diet and local production could be supported by “tapping into the considerable potential of peri-urban agriculture in nourishing large numbers of urban residents.”
So what does this mean for controlled environment agriculture?
Well, first it means that if you’ve conducted an environmental impact assessment comparing your indoor grown produce with imported produce, your figures may not be wholly accurate. It is important to determine these parameters to aid decision making towards when a CEA system such as a greenhouse or vertical farm will have a preferable environmental advantage, and when it won’t. It’s imperative that, as an industry, we really understand the numbers and that we’re as transparent as possible about them. Over the past four years I’ve spoken to hundreds of people in the industry and the common thread that runs through every person is that they want to make a difference. Without a true understanding of environmental accounting, you won’t be able to differentiate where you can make positive change and where you could do more harm than good.
At LettUs Grow, we’re already looking at going back to the drawing board for some of our data. For example, our current estimates say that a DROP & GROW running on wind power is preferable to fresh produce imported from further than 397 km by airfreight or 658 km by refrigerated lorry. However, in light of this new study, the distances food needs to travel before being replaced by produce from a DROP & GROW container farm may shorten significantly - opening up new areas where container farmed produce is a sustainable and viable alternative to imported fruits and vegetables.
The research also indicates that if you’re looking to reduce the global warming potential of food miles, focusing on produce that needs temperature controlled transport will result in the most carbon savings. This information can help guide the types of plants you invest research and development into. That is to say, you’ll see a greater environmental benefit from growing berries than you would from growing, for example, grains. This is because such a large percentage of their total emissions from seed to spoon are associated with refrigerated transport.
Fundamentally, if this research is listened to, it should hopefully act as a wake-up call and galvanise support for increasing domestic food production. In the UK, we import over three quarters of our fruits and vegetables (Source: Feeding Britain) and our horticulture sector has been woefully stripped back to just 3% of farm land use. The study’s authors specifically advocate utilising the potential within peri-urban agriculture. CEA facilities, from greenhouses to plant-factories, are well placed technical solutions for enabling year-round production in peri-urban environments. This research has the potential to generate increased interest in this type of horticulture as a viable alternative to importing certain produce. Rich nations need to reconsider the consequences of their food strategies - the impacts of importing fresh produce can no longer be written off as “negligible”.
Did you find this article useful? If you’d like more breakdowns of industry research or any specific studies summarised, please feel free to forward them to communications@lettusgrow.com or join our mailing list for more updates.
