Curb your appetite!

Centre researcher Max Troell on the spiralling energy use in food production

A calf for his tongue. Livestock production is generally considered to be very energy intensive but a change in consumption patterns is more important for a more sustainable food sector in the future. Photo: B. Ekberg/Azote
In a recent edition of The Annual Review of Environment and Resources, centre researcher Max Troell teamed up with researchers from Canada, the UK, Switzerland, The Netherlands and the US to explain the current drivers and trends in food production energy use.

We asked Max Troell what he considers to be the biggest challenges and opportunities when it comes to energy use in agriculture and food production:

SRC: Max, the world's population is growing and food production volumes are projected to expand substantially. What implications will this have on the energy resources required to produce and store all this food?

MT: Even if we continue to develop and implement more energy efficient technologies the total energy demand will increase because of the increasing volumes needed. We need to reform our energy dependent food production sector, replace fossil fuel energy with renewable alternatives, reduce wastage of food (currently 30-40% of production), and change our choice of food. Our growing appetite for red meat and seafood species, oils, highly processed foods, air-freighted products, and other "luxury" foodstuffs"  imply higher energy costs.

SRC: It's a tall order, but if the world is to achieve its Millennium Development Goal of eradicating hunger, a doubling of food production over the coming 20-30 years is required. Is it possible?

MT: Difficult to say. Eradicating hunger has not only to do with producing a lot of food but this food also needs to be accessible and affordable to people. From an energy perspective we know that the cost for fossil fuel energy will increase on the short term and that this will result in higher production cost for many basic food items i.e. from agriculture, fisheries and aquaculture. So, even if we manage to produce the needed volumes people may still not have access to it. Another short answer to your question could be - yes technically and economically we can today eradicate hunger if we want but for that to happen a stronger political will is needed.

SRC: Much popular discourse on the sustainability of food production has focused on transportation, arguing that small-scale, local food systems use less energy than those dependent on global distribution networks. Is that really so or are things a bit more complicated?

MT: Yes, things are more complicated. Most food systems in industrialized countries are reliant on nonrenewable energy resources, including both direct and indirect life cycle inputs, where production often accounts for the largest proportion of total energy use in the form of artificial heating, fertilizers, tilling, etc. Our paper, as well as many other studies, shows that suitable farming conditions often out-weigh long transportation distances, as these often only constitute a small part of the energy cost. There are of course some types of foods that are very costly energy wise to transport, especially fresh food demanding air transportation.

SRC: Is there a reason to be optimistic about increased use of renewable energy resources in the future?

MT: The proportion of renewable energy resources will definitely have to increase, but together with much more efficient energy consumption. If we are not optimistic about this, our future will look very gloomy. The sad fact is that we could have come much further with respect to renewable alternatives if it wasn't for the relatively easy access to cheap fossil fuel energy. This slows down the process. It will be interesting to see how potential extraction of oil and gas reserves in the Arctic will play in here. Another aspect is that the very large size of the energy transition needed implies that some renewable energy systems may become limited by availability of bulk materials like heavy metals and other resources. So these systems may only be operational under a transition to the next generation of energy systems.

SRC: Over the past 50 years, global fertiliser consumption volumes for crop production have increased dramatically. What are the consequences of this?

MT: Two consequences can be mentioned. First, the easy access and usage of fertilizers has led to abandoning of cultivation methods involving re-circulation of nutrients within the farming system, secondly, overuse of fertilizers generate many negative consequences, including eutrophication of land and water, biodiversity loss, toxicity effects etc. Another aspect is that farmers can get locked into situations where they have become dependent on specific seeds/crops that need specific fertilizers and pesticides to grow. The phosphorous story is also interesting as we seem to have reached the peak for phosphorous production and that this resource will become limiting for agriculture production in the near future.

SRC: What can we do about it?

Better fertilizer practices, involving site-specific application rates, are needed to eliminate over use of  these currently cheap resources. The loop of crop and manure production also needs to be closed again, as manure is often seen as a problem rather than a resource today. There is a strong interplay between use of fertilizers, yields, energy cost and food security. Production of fertilizer is energy demanding and considering the volatility of energy prices, food systems depending on fertilizers will be vulnerable and have important implications for food security.

SRC: How can energy use be reduced in crop production?

MT: In the paper we compare different crop farming systems and it shows that we can change energy consumption significantly depending on how we farm. However, we also show that one specific system may perform differently depending on where it is situated. Not elaborated on in the paper but monoculture systems are often more reliant on anthropogenic inputs, including pesticides and fertilizers, than systems integrating several crops.

SRC: What about livestock production? Generally considered to be very energy intensive, how can this sector decrease its energy use?

MT: This is where we generally find the largest energy consumption within the food sector and it is important to understand the reason for this. Energy associated with growing the feed has been estimated to account for 50 to over 80% of the total energy intensity of livestock products. One can do a lot of modifications to reduce energy consumption. In our paper we point towards several studies that show on-farm energy savings, for example through manure usage. However, these savings are still small compared to the feed related energy use. I think a change in consumption patterns will be key for a more sustainable food sector in the future. Meat could and should be part of our future diet, but not two meals a day, seven days a week. One of the reasons for the current over-consumption of meat is artificially low prices due to large subsidies.

SRC: In terms of fisheries, you mention in the article that rebuilding fish stocks is critical for decreasing fisheries energy use. But how realistic is it that fish stocks will be given proper time and space to rebuild themselves?

MT: It is easy to get pessimistic when realizing that many fish stocks around the world are in bad shape, but there are examples of good governance systems in place. One should learn from these and adapt them to other situations. Of course different approaches will be needed for different situations, but we now know a lot and have developed various tools for management. Aquaculture will need to fill the gap between production and the increasing demand for fish. It is, however, important that we do aquaculture right by choosing the right species and farming methods.

SRC: You mentioned that approximately 30 to 50 % of all the food we produce is wasted, in the US alone, 40% of the available food is wasted. Surely there is an enourmous potential here for the developed world to become more energy efficient. What can we do?

MT: Again - I think changing our life styles - our preferences and our choices - will be more important than structural changes and technology development. Information and education will here be important, as well as industry responsibility. There are different drivers for food waste in developing versus developed countries. The food waste in the developed world mainly occur at or beyond the retailer as a result of high cosmetic demands, currently inexpensive products, an over-belief in “best before dates"  and marketing of over-sized portion/packaging sizes.

SRC: In the midst of all this is the aspect of food security. What linkages are there between energy use and food security?

MT: Energy prices played a central role in the most recent food crises so the link is very strong. It is important that we realize that food production is not an isolated sector but is being shaped and impacted by, and self impacting on, synergistically interacting systems and stressors. Examples are energy but also climate change and global economy - that all can contribute as cross-system stressors.

SRC: Finally, what would you say are among the most promising trends and technologies currently developing in agriculture and food production?

MT: A lot of things are ongoing. At the same time as we see technology development within agriculture we also see more ecological approaches take form within that sector. Since I'm particularly interested in the fishery and aquaculture sectors I think a promising development there is that the ecosystem approach is more and more being acknowledged. This implies that the functioning of many ecosystems, our life support system, is acknowledged and addressed in a multi disciplinary and multi stakeholder perspective. Also the development of feed resources for aquaculture that do not compete with humans for food is promising. Overall, finding solutions to our food problem can only be done by efforts from science, producers, consumers and industry, together.


Pelletier, N., Audsley, E., Brodt, S., Garnet, T., Henriksson, P., Kendall, A., Kramer, K., Murphy, D., Nemecek, T., Troell, M., Tyedmers, P. Energy Intensity of Agriculture and Food Systems. Annu. Rev. Environ. Resour. 2011. 36: 7.1—7.24.

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Max Troell is a system ecologist mainly working with environmental problems associated with aquaculture. This work focuses on inter-linkages between aquaculture and fisheries, on different spatial scales.


Stockholm Resilience Centre is a collaboration between Stockholm University and the Beijer Institute of Ecological Economics at the Royal Swedish Academy of Sciences

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