More fossil fuel energy goes into producing our bread than the energy we will derive from eating it. Growing our economy requires levels of energy that are physically and geologically impossible to deliver.
Imagine the wonderful wafting scents of freshly baked bread. Bread is such a traditional staple of our diets it is likely we never think about its environmental impact.
Life cycle analysis is one way of measuring the environmental impact of products from cradle to grave. A variety of metrics can be produced, but a common one is carbon dioxide equivalents which represents a measure of global warming potential.
If we examine bread, life cycle analysis suggests that the average loaf in your pantry contributed about one kilogram of CO2-equivalents to the atmosphere. The question then arises whether one kilogram of CO2e to transform wheat seed planted on a farm through to bread in the pantry is a sensible expenditure of greenhouse gas emissions.
Some of those emissions arise ‘naturally’ from the soil on the farm through biological metabolism while others are direct and indirect emissions derived from the energy used in bread production from seed to pantry.
Let’s look at the loaf in a different way. The loaf contains about 2000 Calories but based on direct and indirect emissions we can back-calculate that about 2700 Calories of fossil fuel energy was burnt on the farm, within the production chain and at the consumer end to get it to your pantry. Nutritional aspects aside, we can represent this energy balance by borrowing a metric called EROI or ‘energy return on energy invested’ from engineering.
For our loaf of bread we divide 2000 (energy return) by 2700 (energy invested) to get an EROI of about 0.75, where EROI values of less than one are considered unsustainable. That’s quite a dilemma – in order to eat, not only are we producing greenhouse gas emissions, but more fossil fuel energy is associated with our bread than the energy we will derive from eating it.
Where did the process become unsustainable? If we calculate the EROI of the harvested grain at the farm gate it equals about 2.5; that is, for every unit of fossil fuel energy we put in running things like tractors, we receive 2.5 back – a positive return on our energy investment. This is because plants capture energy from the sun and store it in the grain. However, once the grain is transformed into a loaf of bread and arrives in our pantry we have lost the benefit of the free energy subsidy from the sun and end up with an overall net energy deficit.
If we consider the EROI of our broader food production systems, accounting for everything associated with getting food from seed to plate, the net energy deficit gets worse. Currently the EROI for the entire US food production system is a measly 0.12 and if we account for food waste (approximately 40 percent) it drops to about 0.08.
That is, for every calorie eaten a whopping 14 calories of fossil fuel energy was used. The overall EROI for the New Zealand food production system is unknown, but our food waste is on the order of 25 to 30 percent representing a massive loss of resources and energy.
To add insult to injury, we can’t just remove fossil fuels because we need them to deliver and maintain all the components of our renewable energy future and to keep energy supply from ‘renewables’ consistent and useful. At the same time we have an expanding population and energy use expectations.
If we expand the picture further to our global energy supply we can realise the full scale of our predicament. An important number is the EROI at point-of-use where we power things like manufacturing, transport, harvesting grain and baking bread.
Some of this is electrical energy but the majority comes from burning fossil fuels. For example, even with our high percentage of ‘renewable’ electricity, New Zealand’s overall economy is still about 65% fossil fuel powered, while the global situation is worse.
The point-of-use EROI of our global energy supply has gradually dropped. Historically we got a massive EROI because we exploited the easy to obtain energy supplies first. Now the situation doesn’t look as rosy as we only get about 10 units of usable energy for each unit we invest in harvesting energy – an EROI of 10.
This is because we are sourcing a larger proportion of our energy from resource intensive activities like deep sea drilling, fracking and tar sands extraction.
To add insult to injury, we can’t just remove fossil fuels because we need them to deliver and maintain all the components of our renewable energy future and to keep energy supply from ‘renewables’ consistent and useful. At the same time we have an expanding population and energy use expectations.
If EROI drops much below 10 we will no longer be able to maintain our complex civilisation and right now we are in a Red Queen situation – running faster and faster just to stay still.
Getting back to bread, what might the future hold? Theoretically, if renewable energy technologies do improve, and we can maintain a point-of-use EROI of at least 10 but our food production system uses all that energy, then we are in very serious trouble. Goodbye complex civilisation!
To have a truly sustainable future we need to reassess our entire way of life and ‘de-grow’ as we will soon hit the wall and won’t be able to meet our basic needs.
So how do we maximise nutrition and minimise energy loss?
Well, we can begin this process by drastically reducing food waste. We can refuse exotic imported delicacies and eat food that is produced locally. We can eat seasonally. We can get organised and shop less frequently and in bulk for non-perishable staples. We can walk or cycle to our local corner shop for perishables. We can work towards low-input, energy and resource efficient farms to increase the farm gate EROI. We can take a serious look at energy wastage in food production chains beyond the farm gate.
We can eat foods that are less-processed. We can refuse foods that are sent overseas for processing and packaging and then shipped back here despite the ingredients being produced locally. We can plant a vegetable garden and make compost. We can cultivate road verges. We can support local community gardens and food forests.
We can refuse to reinforce a perverse economic system that forces our food producers to behave in unsustainable ways to remain ‘competitive’. We can live as our grandparents lived.
Our economic future has always been painted as one of ‘growth’ within a sustainable techno-utopia. But expanding activities (or even maintaining activities) in our economy requires levels of energy that are physically and geologically impossible to deliver.
To have a truly sustainable future we need to reassess our entire way of life and ‘de-grow’ as we will soon hit the wall and won’t be able to meet our basic needs.
Of course, all this assumes we still have a stable climate and functional ecosystems from which to grow and harvest food.
