i School of GeoSciences DISSERTATION For the degree of MSc in Environmental Sustainability Student Name: Stefan Sagrott Date: August 2011
Apr 21, 2015
i
School of GeoSciences
DISSERTATION
For the degree of
MSc in Environmental Sustainability
Student Name: Stefan Sagrott
Date: August 2011
i
Organic Farming and Local Food: Life Cycle Analysis of Breadshares
Bakery Bread
By
Stefan C. Sagrott
Dissertation presented for the MSc in Environmental Sustainability, August 2011
ii
THE UNIVERSITY OF EDINBURGH
Name of Candidate Stefan Sagrott
Address Centre for the Study of Environmental Change and Sustainability, University of Edinburgh, Crew Building, King's Buildings, West Mains Road, Edinburgh EH9 3JN
Degree MSc Environmental Sustainability Date 17th August 2011
Title of Thesis Organic Farming and Local Food: Life Cycle Analysis of Breadshares Bakery Bread
Background, aim and scope This study has aimed to calculate the carbon footprint of a loaf of bread produced under by the Breadshares Bakery. The bakery is based on an organic farm, using wheat grown on the farm, reducing transport for ingredients and is powered by a on-site wind turbine. The functional unit is defined as “one loaf (990g) of wholewheat bread consumed at home”. As well, a number of topics including food miles, energy use in agriculture and the benefits of organic farming are discussed.
Methodology The study has been carried out in accordance with the PAS 2050 methodology. Primary data compliant with PAS 2050 has been collected from the farm and bakery operations. Secondary data is sourced from LCA databases, government sources and other published works.
Results and discussion The carbon footprints calculated range from 0.39 kgCO2e per loaf of bread to 0.47 kgCO2e per loaf of bread. The main hotspots for emissions are wheat cultivation and bread consumption.
Conclusions When compared with the carbon footprints of other British breads, the Breadshares loaf is between 50% and 66% lower, highlighting the carbon savings that can be made by using organic wheat and shortening the production chain.
No. of words in the main text of Thesis 17,577
ABSTRACT OF THESIS (Regulation 3.5.13)
iii
'I hereby declare that this dissertation has been composed by me and is based on my own work’.
Stefan Sagrott
August 2011
Acknowledgements
I would like to extend my thanks to those who have provided valuable assistance and
advice at some stage during the preparation of this dissertation:
Dr. Kairsty Topp
Dr. Meriwether Wilson
Mrs Christine Wilson
Mr Roland Playle
Mr Andrew Whitley
Ms Veronica Burke
Mr Pete Ritchie
Mrs Jessica Sagrott
Any errors remain the responsibility of the author.
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Table of Contents
Chapter 1 Introduction 1 Section 1.1 Project & Aims of the Project 1 Section 1.2 The Environmental Impact of Mankind 3 Section 1.3 A History of Bread 15
Chapter 2 The Life Cycle Analysis of a loaf from
the Breadshares Bakery 23
Section 2.1 Life Cycle Analysis 23 Section 2.2 Methodology 27 Section 2.3 Data Sources 34 Section 2.4 Results 36
Section 2.4.1 Life Cycle Inventory 36 Section 2.4.2 Life Cycle Inventory Analysis 39 Section 2.5 Discussion 46
Chapter 3 Food, Farming and Sustainability 49 Section 3.1 Introduction 49 Section 3.2 Energy Use in Agriculture & Peak Oil 50 Section 3.3 Conventional & Organic Farming:
A Comparison 57
Section 3.4 Local Food Production, Food Miles & Sustainability Implications
66
Chapter 4 Conclusion 71
Appendix A Detailed Calculations for Life Cycle Inventory Analysis
72
Bibliography 75
v
List of Figures & Tables
Figure 1.1 Trends in human activity observed since 1750 8 Figure 1.2 Trends resulting from increased human activity since 1750 9 Table 1.1 GWP and residence time of Greenhouse Gases 10 Figure 1.3 Changes in greenhouse gas concentration 1700-present 11 Figure 1.4 Global annual mean surface temperature 12 Figure 1.5 Past global mean temperature change and predicted future
changes 13
Figure 1.6 Saddle quern 15 Figure 1.7 Reconstructed rotary quern 17 Figure 1.8 Roller milling 18 Table 1.2 Vitamin and mineral loss in white flour
with a 70% extraction rate 20
Table 2.1 Ingredients of a Breadshares Bakery loaf 29 Figure 2.1 Energy flows for ‘cradle-to-grave’ analysis of Breadshares loaf 36 Figure 2.2 Detailed energy flows for the Raw Materials stage 37 Figure 2.3 3 Detailed energy flows for Processing stage 37 Table 2.2 Emission results for the organic wheat 38 Table 2.3 Carbon footprint of each raw material 39 Table 2.4 Carbon footprint of a loaf under each scenario 40 Figure 2.4 Breakdown of the 3 carbon footprints 41 Figure 2.6 Breakdown of carbon footprint for Scenario A loaf 42 Figure 2.7 Breakdown of carbon footprint for Scenario B loaf 43 Figure 2.7 Breakdown of carbon footprint for Scenario C loaf 44 Table 2.5 Comparison of the carbon footprints of different breads in
different studies 45
Table 2.6 Relative contribution of the life cycle stages to the carbon footprint of the breads
45
Figure 3.1 Primary energy use in agriculture 1971-1995 50 Figure 3.2 Hubbert’s bell curves for global peak oil 51 Table 3.1 Studies suggesting peak oil dates 51 Figure 3.3 Energy and food prices 1992-2008 53 Table 3.2 The effects of organic farming on biodiversity, compared to
conventional farming 60
Figure 3.4 Sources of N2O and CH4 emissions in the USA 62
1
Chapter 1
1.1 Aims of the Project
This project aims to calculate the carbon footprint of a loaf of bread, baked under the
Breadshares Community Bakery scheme, from cradle-to-grave. This means that the
full lifecycle of the bread, from the raw ingredients all the way though to the disposal
stage will be evaluated for its carbon (or carbon equivalent) emissions.
Breadshares is a Community Interest Company based at Whitmuir Organic Farm in
the Scottish Borders. Established in 2011 it has the aims1 of:
• making excellent, nutritious, affordable, organic bread, biscuits, cakes and
more
• bringing bread to local markets, village halls, community meeting places and
small businesses
• giving all kinds of people the chance to learn and practise baking skills
• helping to create a more sustainable and health-enhancing local food system
• developing links between small businesses, local growers and producers in
Peeblesshire
The bread at the bakery will be made using local organic produce; with the wheat
either being grown on site or imported from farms within the local area are certified
by the Soil Association.
Bread has been the staple food for most of the world since it was first baked in the
Fertile Crescent some 10,000 years ago. In Britain, the majority of the bread
consumed in Britain during the last 50 years has been manufactured through the
Chorleywood Process, which has created a trade-off between bread quality and price,
resulting in cheap and malnourished bread, with many British people unaware of what
really goes into their daily bread. The Breadshares scheme aims to change this, on a
small scale, by teaching individuals how to make bread using the purest, most natural
ingredients possible.
1 http://www.breadshare.co.uk/
2
Of particular interest to the founders of Breadshares is the environmental impact of
modern food, with the large, centralised manufacturing and distribution hubs involved
in the supply chain. Whitmuir Farm is a certified organic farm and all produce sold in
the farm shop and produced by the Breadshares Bakery is organic. To this end, the
Bakery directors commissioned this life cycle analysis to be carried out so that the
environmental impact of the loaves could be evaluated.
The initial hypothesis is that the carbon footprint of a Breadshares loaf will be
significantly lower than that of a loaf available to purchase from any major retailer.
This is expected since wheat is grown organically and hence has no chemical inputs,
there is no transport involved, aside from within the farm and the majority of the
electricity used is generated by an on-site wind turbine.
The parameters of the study, as well as the data and results of the life cycle analysis
can be found in Chapter 2.
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1.2 The Environmental Impact of Mankind
Over the past three centuries human activities have changed the makeup of the earth
system. Increasing globalisation, population, urbanisation and consumption have
placed greater demands on the earth’s resources than ever before. The use of these
resources, especially the burning of fossil fuels, as well as the global change of land
use, has altered the balance of gases in the atmosphere resulting in global warming
etc.
Prior to 1750 (the commonly recognised start of the Industrial Revolution), the
foundations of daily life in Britain had remained relatively unchanged from thousands
of years before (Kussmaul 1990). Britain’s population had increased gradually from
around 4 million at the start of the 17th century to 6.5 million by 1750 (Clarkson
1972:26; King & Timmins 2001:210). The majority of these people were employed in
agriculture (Clarkson 1972:10; Daunton 1995) which was, on the whole, a subsistence
activity and was still carried out using methods and practices brought to Britain
thousands of years ago. All work was carried out by manual labour (Clarkson
1972:13); ploughs were pulled by animals or humans, seeds sown by hand and crops
harvested using scythes with the produce being taken from the field by horse and cart.
Fires fuelled by wood, and to some extent by the 18th century coal, provided heat for
cooking and warming the home (Clarkson 1972:13); the smoke could be used to
preserve meats, as refrigeration in the form of ice houses was restricted to the upper
classes and light around the home was provided by foul smelling oil lamps and
candles.
The only alternative sources of energy available were wind and water power, both of
which were harnessed to turn equipment in cotton mills and millstones, grinding
wheat into flour for use in baking bread, the staple food for most of history (Daunton
1995:26).
A lack of conspicuous consumption, except by the upper class, and a fairly low
population (around 9m for the United Kingdom in the early 18th century) coupled with
the above meant that there was minimal use of environmental resources except for
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wood and coal. Thus the ecological footprint (Rees 1992) of life at the time would
have been very low.
The Industrial Revolution as the period after 1750 is known brought about great
technological changes with knock on effects that would have a profound effect on not
just Britain but the world. Early technological advances such as Jethro Tull’s seed
drill, which mechanically sowed seeds and turned over the furrow, and the
introduction of the four field rotation system (Ashton 1977:21-22) lead to improved
yields in both quality and quantity (Daunton 1995:40). The introduction and
subsequent widespread adoption of the iron plough and Meikle’s threshing machine
reduced the size of the workforce required for agriculture. The upshot of this was that
the yield per worker from agriculture increased, as yields went up and the number of
workers decreased. More food was available not only to feed a growing population,
but also for export and the redundancies brought about by the introduction of
machinery would provide for the burgeoning industrial workforce (Daunton 1995:39).
The two drivers that sparked the industrial revolution were the invention of the steam
engine (Ashton 1977:55-58) and the widespread adoption of coal as a fuel; this
allowed the manufacture of purer iron (both wrought and cast) in greater quantities.
The steam engine made two major changes in the fabric of British industry. Firstly it
allowed for the centralisation of manufacturing processes into one factory.
Traditionally work such as spinning and weaving had been part of a cottage industry
carried out in the home, although larger scale production centres did exist. Steam
engines allowed not only for the work to be undertaken in one place, but that the
factory could be sited away from the type of water sources required for mills (fast
flowing and steady supply), opening up vast areas of the country as manufacturing
areas.
The advent of quicker and cheaper iron production allowed Britain to move away
from importing iron from Russia (Ashton 1977:54), and it was not before long that
iron replaced wood and stone as a building material and was used in every walk of
life; agriculture, engineering, transportation, and textiles (Ashton 1977:55).
5
It was around this time that the first musings on environmental limits were put to
paper; in 1798 Thomas Malthus, a preacher from Surrey, published the first edition of
his work An Essay on the Principle of Population. The premise of the works was
Malthus’ theory that whilst population would increase exponentially, food production
could only grow geometrically; meaning that at some point population growth would
outstretch food production resulting in famine. This famine, Malthus suggested,
would reduce the population to a level that could be supported by the food
availability.
A Malthusian situation has not yet occurred despite a tenfold increase in Britain’s
population due to technological advances that have increased yields (c.f the green
revolution) and the ability to import food from abroad.
Once the basis of the Industrial Revolution had been established it allowed for a
whole magnitude of scientific discoveries and inventions. Civil engineering projects
such as canals and bridges were undertaken, and expansion took place in every walk
of life. Urbanisation increased as factory workers moved to cities to live closer to
their workplaces and manufacturing & industrial outputs increased. Railways,
powered by coal, allowed for the mass transport of people and goods over great
distances. As the pace of the Industrial Revolution increased, more resources were
required and this period represents the first time that resources were exploited on a
large scale and in a systematic way (although it should be noted that resource use,
namely metal smelting, by the Romans and Greeks during the 1st Millennia BC and
AD has been detected in Greenland ice cores); and is a trend which continues on a
even greater scale to this day. Between 1800 and 1900 the consumption of coal in
Britain increased from 10 million tons to 167 million tons per annum (Clapp
1994:16).
It stands to order that the use of any resource produces waste and Victorian Britain
was no different. With the adoption of coal as the fuel of choice and much of the new
industry involved burning coal, smelting metals and so forth, it is hardly surprising
that air pollution in urban areas became a big issue. It has been estimated that by the
early 20th century Sheffield was receiving deposits of 55 tons of solids per square mile
every month (Clapp 1994:14). It must be noted that prior to the 1970s most cases of
6
pollution were thought of as isolated, local issues rather than as part of a larger system
with the capacity to have impacts across the entire planet (Clapp 1994:57).
As the use of coal expanded into other fossil fuels such as oil and gas, it increased
mankind’s capacity to “extract, consume & produce” (Grübler 1998), although the
19th century had experienced a 5 fold increase in energy use, that was a mere drop in
the ocean compared to the 16 fold increase in energy use during the 20th century.
This new capacity caused not only an enormous growth in population from 1bn in
1800 to 6bn in 1999 (with a projected rise to 9bn by 2050) (Steffen et al 2005:81) but
also allowed for natural resources to be discovered, extracted and used quickly, and in
large amounts.
Increases in population, as well as the subsequent economic increases and
improvements, which have raised both life expectancy and lifestyle expectancy, have
placed an increasing demand on the whole spectrum of Earth’s resources (Steffen et
al 2005:81); the impact of such a relationship is demonstrated by the IPAT equation:
I = P x A x T
Where I = impact, P = population, A = affluence and T = technology (Ehrlich &
Holdren 1971)
Whilst not particularly useful over short time scales, the equation can provide
interesting data, and thus an insight into the impact of human activity over a time
scale of decades or even greater (Steffen et al 2005:84).
It can be said that we are living far more comfortable lives than at any other point in
human history, in the developed world at least, however there is a significant
environmental cost associated with this.
Virtually no part of the planet remains untouched by development; there has been
mass land use change, biotic additions & losses, a loss of biodiversity and mass
extraction of minerals from increasingly remote and fragile locations. The rate of
7
tropical deforestation has been as high as 4% per year (Steffen et al 2005:98) and it
has been calculated that we have cut down more than a third of the world’s trees.
Biodiversity has been thinned by human activity; current rates of extinction are 100 to
1000 times greater than in pre-human times (Pimm et al 1995). Up to 20% of all birds
and 39% of all mammals & reptiles are threatened by extinction and between 22-47%
of all plant species are in danger of becoming extinct (Pitman & Jorgensen 2002;
Steffen et al 2005:118). Humans have made wholesale changes to natural habitats by
introducing non-native species to areas; 20% of plant species in continental areas are
non-indigenous, rising to 50% or higher on many islands (Rejmanek & Randall 1994).
The ecological footprint (i.e. humankinds demand on resources) is now 2.5 times
greater than what it was before the industrial revolution, and we have crossed the one
planet boundary, meaning that we are living beyond our means, beyond what the
planet can naturally support.
This period from 1750 has been deemed ‘The Great Acceleration’ by a number of
researchers, as progress and development have increased at such a rapid rate (Steffen
et al 2005). Figure 1.1 below shows a selection of the major trends in human activity
observed since the start of the Industrial Revolution and Figure 1.2 shows trends
resulting from human activity.
8
Figure 1.1 Trends in human activity observed since 1750 (From Steffen et al 2005:132)
9
Figure 1.2 Trends resulting from increased human activity since 1750 (Steffen et al 2005:133)
The loss of biodiversity is not only a concern relating to a decline in species but can
also be linked to wider issues. The natural world provides many processes that are
beneficial, or even critical, to mankind. Such processes include nutrient cycling,
purification of air & water, generation of soil and pollination of crops & vegetation.
The Millennium Ecosystem Assessment (2005) calculated that the value of ecosystem
services in 1997 to be in the region of $33 trillion per year. This is best highlighted by
a case study from Maoxian County, China. Here the decline in bee numbers,
10
attributed to increasing human activity, especially the use of pesticides, has resulted in
farmers having to pollinate apple trees by hand. 20-25 people are required to perform
the work of two bee colonies (Steffen et al 2005:248-9) bringing about an additional
expense for the apple growers.
Another consequence of increasing global development are the changes to the planet’s
atmosphere. Through the use of CFC’s mankind has already altered the atmosphere
by depleting the ozone layer (Middleton 1999:148) and this prompted a quickly
implanted ban on the use of CFC’s. In addition there is also the rather well known
issue of global warming. Deforestation and the combustion of fossil fuels have
released greater amounts of carbon dioxide (CO2) into the atmosphere than ever
before (NAS 2008:7). Carbon dioxide, along with the other greenhouse gases (GHG)
of water vapour, methane, nitrous oxide and ozone, cause positive radiative forcing
(IPCC 2001:5); whereby thermal radiation emitted either by the earth or entering the
atmosphere from the sun are trapped by the gases, increasing the global temperature.
The other greenhouse gases are measured in relation to their global warming potential
(GWP)2. Carbon dioxide is the baseline figure and has a GWP of 1. Methane (CH4)
has a GWP of 25 and has risen from a concentration of 670ppb in pre-industrial times
to 1700ppb presently (Steffen et al 2005:101), with the majority of methane emissions
coming from agriculture and the decomposition of organic materials.
Greenhouse Gas Residence time (years) GWP (100 year horizon) Carbon Dioxide 5-200 1 Methane 12 25 Nitrous Oxide 114 298 HFC-23 260 14,800 HFC-134a 13.8 3,380 Sulphur hexaflouride 3200 22,800
Table 1.1: GWP and residence time of Greenhouse Gases
Nitrous Oxide (N2O) has a GWP of 298 and its atmospheric concentration has
increased from 285ppbv to 310ppbv (Steffen et al 2005:103), with around a third of
N2O emissions being anthropogenic (mainly agriculture) (IPCC 2007:7).
2 GWP in 100 year time horizon
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Currently carbon dioxide emissions stand at 26.5 GtCO2 per year (IPCC 2007:2) of
which three quarters is attributed to fossil fuel burning, with the rest being caused by
changes in land use, especially deforestation (IPCC 2001:7).
Figure 1.3: Changes in greenhouse gas concentration 1700-present (Steffen et al 2005:103)
Since 1750 the global atmospheric concentrations of CO2 have increased from
280ppm to 379ppm in 2005 (IPCC 2007:2) and is currently at the highest
concentration for 650,000 years (IPCC 2007:2; NAS 2008:2). At the same time,
global average surface temperature has increased by 0.6ºC (IPCC 2001:5) (Figure
1.4). The IPCC 4th Assessment (2007) concluded that by 2100 global temperatures
will have likely risen by 1.1ºC-6.4ºC (IPCC 2007; NAS 2008:8), although as these are
only model predictions, uncertainties remain (Figure 1.5).
12
Figure 1.4: Global annual mean surface temperature (Steffen et al 2005:129)
The increase in global temperatures has had a number of impacts around the world
(Steffen et al 2005:203,249); a decline in mountain glaciers (e.g. Kilimanjaro) and
global snow cover has been observed and these have contributed to global sea level
rise (a rate of 1.8mm/year between 1961-2003) (IPCC 2007:5-7) and further increase
in temperature are likely to see sea level rises between 0.18m and 0.59m (NAS
2008:8). Any future sea level rise will have large effects on many low lying island and
coastal regions world wide; islands such as the Maldives, the Marshall islands, Tuvalu
13
as well as cities such as Venice, Tokyo and Bangkok which are all at risk of flooding
(Middleton 1999:157). Changes in polar ice have been observed and although these
do not contribute to sea level rise they can be linked to habitat loss and albedo change.
Other effects include changes in ecosystems (including species extinction and changes
in animal & bird migration) and changes in global and regional climate & weather
systems, which could lead to increases in extreme climatic events such as droughts
(Middleton 1999:155).
Figure 1.5 Past global mean temperature change and predicted
future changes (Steffen et al 2005:149)
Of particular concern to this project is the issue of food security. Most reports suggest
that the impacts of global warming will vary between regions; with a generalised
sweep that crop yields in low latitudes will decrease, whilst yields in high latitude
areas will increase. Europe could see a 25% increase in yields (Steffen et al 2005:217)
whilst areas such as Pakistan could see up to a 50% decrease in yields (IPCC
2007:14). Those who will be hit hardest by climate change are those who can ill
afford it.
Agriculture is currently a large contributor to global GHG emissions. Fossil fuels are
intensively used in making agro-chemicals (especially through the Haber-Bosch
process) as well as being used to power machinery and other equipment. Growing
crops, especially legumes and the use of N-based fertilisers, as well as changes in land
14
use and emissions from agricultural soils have lead to increasing amounts of N2O in
the atmosphere; whilst the decomposition of crop wastes and emissions from cattle
have added extra CH4. Although it should also be remembered that crops and plants
can act as sinks for CO2, removing it from the atmosphere.
As wider concepts of sustainability and sustainable development have emerged,
agriculture has been a sector targeted for a reduction in emissions. Organic farming
has the potential to significantly reduce emissions, as it does not use any chemical
inputs to the field, however in some circumstances this can potentially lead to
increased emission as more machine hours are required to carry out the work. The
case for organic vs. conventional farming, as well as other issues relating to food,
farming and sustainability are examined in Chapter 4.
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1.3 A History of Bread
The first real indications of bread come from the Neolithic period some 10,000 years
ago; although recently some scant evidence for the use of grinders and pounders on
dry seeds dating to the Epipaleolithic may point towards an early form of flour, and
perhaps bread (Watkins 2005:209). Starting in the Fertile Crescent (modern day Iraq,
Syria, Jordan, Lebanon, Israel and Iran) and gradually spreading out across Europe,
arriving in Britain around 4000 BC (Whittle 1999) farming allowed the inhabitants of
Britain to adopt a sedentary lifestyle; growing crops and domesticating animals.
Saddle querns (Figure 1.6) dating back to this period have been found in Britain, and
would have been used to grind cereals into flour. Despite this, no-one is precisely able
to say when bread was first baked, and its discovery was most likely accidental!
The earliest breads we know of, from the Middle East, were unleavened flat breads
baked on heated flat stones or straight in the embers of a fire (Marchant et al
2008:16). Dough left alone, naturally rises and again it is not known when the switch
from unleavened bread to leavened bread took place. Preserved loaves of bread, along
with tools and cereal remains have been excavated from the Neolithic lake villages in
Switzerland (Ashton 1904:13; Marchant et al 2008:16).
Figure 1.6: Saddle quern (National Museum of Wales)
Archaeological evidence shows that around the world, breads were made depending
on the cereals available in different regions; wheat was used in the Middle East, North
Africa, Europe, southeast Asia and India; rice was used in East Asia, maize in the
Americas and soghum in sub-Saharan Africa (Scarre 2005:191).
16
Of the wheat used in Europe, different varieties were available; einkorn, emmer, spelt
club and durum were used in varying regions, each suited to different climates and
soils, with the varieties providing different properties for use in bread making
(Marchant et al 2008).
In prehistoric Britain, emmer and spelt were the most popular varieties of wheat
(Reynolds 1978:58), and both have made a recent resurgence with flour made from
both species available to be bought in many shops3. Technological developments such
as the introduction of metals improved the efficiency or agriculture; bronze then iron
was used as scythe blades, iron was used instead of stone for ard shares and also
allowed for the development of the rotary quern, the forebearer to millstones, which
greatly increased the efficiency of grinding wheat into flour (Marchant et al 2008:18-
19). Archaeological discoveries such as large pits and four poster structures have been
interpreted as early granaries (Reynolds 1978) and suggest that Iron Age Britons were
storing grain for winter. A wooden butter dish found at Oakbank Crannog, Loch Tay
may indicate that bread in the past was consumed in a similar manner to modern day,
with butter spread on it (Dixon 2004:150).
When the Romans invaded Britain they brought with them the watermill. (Marchant
et al 2008:41) as well as specialised bread ovens. Excavated examples of these are
known across Britain, usually associated with Roman settlements and temporary
marching camps (Cook & Dunbar 2008; Marchant et al 2008:41). After the Romans
withdrew from Britain and the country entered into the period known as the Dark
Ages it appears that the technological progress was lost. Indeed it wasn’t until the end
of the First Millennia AD that the watermill re-appeared, but by the time of the
Doomsday Book in 1086 there were over 6000 of them (Marchant et al 2008:42).
It was around this time too that windmills first appeared in the British countryside.
Legend has it that they were brought to Europe by Crusaders returning from the Holy
Land (Ashton 1904:103), although there is no evidence to support this. Either way by
3 http://www.shipton-mill.com/flour-direct-shop/speciality-and-rare-flours/shop-47/organic-emmer-wholemeal-414 & http://www.dovesfarm.co.uk/flour-and-ingredients/organic-flour/organic-white-spelt-flour-x-1kg/
17
the year 1300 there were over 4000 operating in England (mainly in the East)
(Marchant et al 2008:44).
Figure 1.7: Reconstructed rotary quern4
Aside from design changes in windmills, the development of dedicated bakeries &
bread ovens and the introduction of various laws, taxes and guilds very little changed
in the bread industry until the Industrial Revolution (Ashton 1904; Marchant et al
2008).
For most of its history, bread has been a status symbol. In ancient Rome, rye bread
was desirable and eaten by the wealthy, whereas having to eat barley bread was seen
as a punishment (Marchant et al 2008:24-5). Until the 20th century in Britain, white
bread was eaten by high society and brown bread by the poor (Marchant et al
2008:29-31, 134); as white bread had undergone more processing and was easier to
chew, it was seen as a luxury item. Conversely brown bread was rougher, cheaper and
harder on the teeth.
4 https://picasaweb.google.com/BodgitandBendit/ReplicatedArtifacts#5020729258135659842
18
Flour and bread making was a quick adopter of the new technology introduced during
the Industrial Revolution (Marchant et al 2008:51). Steam power gradually replaced
water and wind, reducing the industry’s reliance on nature (and thus removing the
location advantage of some areas of the country) and allowing for greater flour yields
(Marchant et al 2008:64-5). Other technological developments included higher
capacity & greater efficiency ovens, mechanical mixing, slicing and wrapping
machines (Marchant et al 2008), with arguably the biggest development being the
introduction of roller milling, although it has been argued that this was also a large
step backwards for nutrition (Marchant et al 2008; Whitley 2009: Alexander
2010:128).
Figure 1.8 Roller milling5
Roller milling works by passing the wheat through pairs of revolving steel rollers,
with the gap between each roller getting successively smaller and smaller (Ashton
1904; Marchant et al 2008; Alexander 2010). After each roller, sieves separate the
different sized particles, allowing them to be put back through the system, reducing
them to fine flour (Ashton 1904:111). Since the rollers could exert more pressure on
the wheat, they could handle the harder wheat’s of Canada and the USA opening up
export markets that flooded the UK with cheaper wheat.
Rather than grinding like a typical pair of millstones, the roller mils scrape and peel
the endosperm from the bran, which is then discarded for other uses (Gélinas et al
2009:525). The main problem with this is that the endosperm contains many of the
vitamins and nutrients found in wheat, and thus the peeling and discarding of it,
removes these nutrients from the flour. Estimates suggest that up to 80% of the 5 Image from: http://www.dovesfarm.co.uk/about/the-history-of-bread/the-history-of-bread-the-industrial-revolution/
19
original vitamins are removed from the resulting white flour (Table 1.2) (Whitley
2009; Alexander 2010:182). The increase in pellagra (a Vitamin B deficiency) in the
United States during the early 20th century has been linked with the adoption of roller
mills (Alexander 2010:183).
The roller milling method proved so successful in destroying the nutritional value of
bread, that by 1911 it had become a national controversy, and became a major selling
point for brown and wholemeal bread. During WWII a number of changes were made
to bread to increase its nutritional value; first extraction rates of the flour were raised
meaning that more of the nutrients made it into the flour; secondly the use of
bleaching agents to make flour whiter was prohibited; thirdly vitamins such as
calcium, thiamine, niacin and iron were added into white flour (a practice which
continues to this day) (Whitley 2009:25).
It was during the 20th century that the long standing status quo changed; white bread
became the norm, whereas brown & wholemeal breads became a luxury item
(Marchant et al 2008; Gélinas et al 2009). The innovations discussed, led to a drop in
the price of bread but this was accompanied by a drop in consumption levels as well.
By the end of WWII British baking had become dominated by three main companies:
Rank-Hovis-McDougall, Spiller-French and Allied Mills. With the end of rationing,
the price of bread rose, and consumption dropped further.
The development that has had the greatest effect on bread, and is responsible for the
light, fluffy, soft crusted and tasteless bread on sale today is the Chorleywood Bread
Process (CBP) (Lawrence 2004; Marchant et al 2008; Whitley 2009).
Introduced in the early 1960s by the British Baking Industries Research Association
(Lawrence 2004; Marchant et al 2008), CBP allowed soft British wheat, with a lower
protein content (Whitley 2009:7) that is not usually suitable for baking to be used in
bread production (Marchant et al 2008:164). By incorporating air and water into the
dough at high speeds, and by using at least double the quantity of yeast (Lawrence
2004:106) it was possible to produce bread in 40% of the time required for traditional
bread (Marchant et al 2008:167).
20
Nutrient Loss (%)Thiamine (B1) 77 Riboflavin (B2) 80
Niacin 81 Pyridoxine (B6) 72 Pantothenic Acid 50
Vitamin E 86 Calcium 60
Phosphorous 71 Magnesium 84 Potassium 77 Sodium 78
Chromium 40 Manganese 86
Iron 76 Cobalt 89 Zinc 87
Copper 68 Selenium 16
Molybdenum 48 Table 1.2: Vitamin and mineral loss in white flour
with a 70% extraction rate (Whitley 2009:23)
The Chorleywood method is only successful if additives are used to make the bread
(Lawrence 2004:106, 108-9; Whitley 2009:7-13); hard fat with a high melting point is
required to give the bread structure, emulsifiers provide volume to the bread, as does
L-ascorbic acid by increasing gas retention. Various preservatives are added to
increase shelf-life and numerous enzymes are added to carry out various functions,
but since they are destroyed during the baking process they do not have to be declared
on the label.
Due to the short fermentation time, flavour is unable to develop and extra salt has to
be added (around 0.5g per 100g of sliced white bread) to compensate (Lawrence
2004:108). Extra water is added to increase volume to the extent that the average loaf
made via CBP is 45% water.
The Chorleywood Bread Process is also incredibly energy intensive. Prior to the
industrial revolution, bread was completely hand made and then baked in open fires
(also used for cooking and heating) or wood-fired ovens. The Industrial Revolution
introduced machinery to the baking process, powered by coal, gas and then electricity.
The CBP is a wholly mechanised system, where ingredients weighing over 300kg are
21
fed into mixers, which turn them into dough in three minutes. The dough is then
placed on a conveyor that transports it through machinery that shapes, divides, proves,
and bakes the bread for 54 minutes (where it is constantly moving pass gas burners)
before being cooled for 110 minutes (the most energy intensive process).The bread is
then sliced, and wrapped ready for distribution across the entire UK (Lawrence
2004:112-113).
The end result of all this is that, despite the wide range of breads available in the UK:
sourdoughs, rye breads, ciabatta, baguettes, pizza dough, wholemeal, pitta bread,
flatbreads (Whitley 2009) 80% of the UK’s bread is made using the Chorleywood
process. One factory in England produces 10% of all the bread, turning 820 tonnes of
flour into 1.5million loaves a week (Lawrence 2004:111). Bread can now be bought
for as cheaply as twenty pence a loaf and it has been suggested that there are a
number of health issues, including thrush, celiac disease, wheat & yeast intolerance
(Whitley 2009:4) caused by Chorleywood made bread6.
To this end Andrew Whitley, a baker, and former owner of the Village Bakery in
Melmerby started the Real Bread Campaign7 with the aim to “bring real bread back
into the hearts of local communities” and make it:
• better for us
• better for our communities
• better for our planet
Andrew is now the mentor for the Breadshares Scheme, which has aims very closely
linked to those of the Real Bread Campaign.
The availability of cheap, long lasting bread from supermarkets and other high street
stores, where it is often sold as a loss leader (Lawrence 2004; Whitley 2009) was the
last nail in the coffin of community artisan bakers. At the start of the 20th century
there were 12,000 registered master bakers in the United Kingdom but by 1995 there
were only 3,000 (Marchant et al 2008:220).Unable to compete with the supermarkets,
these statistics reflects a wider trend observed on the high street in recent years
(Lawrence 2004:123). The decline of the British high street has been linked with a 6 For a further discussion of these see Whitley (2009) Chapter Two. 7 http://www.sustainweb.org/realbread/
22
reduction in community spirit and social cohesion. Whitley (2009:243) sees the eating
of bread bought from a local baker as providing “a more profound sense of
connectedness with the community and the natural world that sustains it”.
However, since 1995, 500 new master bakers have registered in Britain and their
popularity can be seen in many affluent areas, with people queuing out of the doors
early on a Saturday morning. Some have argued that this past-time is now an “organic
living, middle class cliché” (Siegle 2011) rather than a wider reflection of British
society.
Home baking has also regained popularity, with an increase in the sales of
breadmakers and breadmaking books. In 2008 the homebaking market in the UK was
worth £491 million (Marchant et al 2008:222).
Perhaps all is not lost for the humble loaf.
23
Chapter 2: The Life Cycle Analysis of a loaf from the Breadshares
Bakery
2.1 Life Cycle Analysis
Life cycle analysis (LCA) is increasingly being used by companies to examine the
environmental impacts of products and services they provide (Nissinen et al
2007:538; Espinoza-Orias et al 2011:352).
It is a method of calculating the greenhouse gas emissions (GHG) generated during
the product’s lifetime (known as the cradle-to-grave approach) and is more commonly
referred to as ‘carbon footprinting’ (BSI 2008b:1-2).
The data generated by an LCA can be used internally and externally by a company.
Internally the data can be used to (ISO 2006; BSI 2008a, 2008b):
• Identify cost savings
• Carry out carbon accounting and thus;
• Reduce GHG emissions across the company
• Incorporate lessening environmental impacts into product design and company
strategy
• Move to a more environmentally friendly supply chain
Externally the data can be used to (ISO 2006; BSI 2008a, 2008b):
• Demonstrate corporate responsibility
• Inform customers & investors on product impacts
o Eco-label/market products
• Meet demands from ‘green’ consumers
• Promote sustainable consumption (Nissinen et al 2007:538)
Carbon footprinting allows consumers to connect the products they buy with
environmental problems that occur in distant places and times (Nissinen et al
2007:538) empowering the consumer to make more responsible decisions.
24
A number of criticisms have been directed at the LCA method recently, mainly due to
their inaccessible nature: “LCA reports are extremely technical, featuring long lists of
environmental pollutants and abounding with technical terms. They are not directed
at lay people who need to get a quick overview” (Nissinen et al 2007:538). At the
other end of the scale LCA results can be oversimplified for the consumer, with the
results often being converted into equivalents for comparison, such as equal to driving
a medium sized car for x miles, distancing the project from the environmental
information trying to be put across.
Studies such as Nissinen et al (2007) have attempted to develop and evaluate
benchmarks for life cycle assessment based environmental data, with the conclusion
that a scale based system against which different products can be plotted is the most
favourable amongst tested consumers.
Recently the carbon footprint of foods has become a burgeoning topic and this is
reflected in the literature. As consumers have become more environmentally aware
and started to take an active approach in purchasing sustainable products, it is hardly
surprising that manufacturers have sought to evaluate and place carbon footprint
labels on produce.
Produce perceived as being more sustainable and environmentally friendly such as
organic foods have been becoming increasingly popular. In 2009 the organic produce
market in the UK was worth £1.84bn (Soil Association 2010:4) and it is estimated
that the market will expand by 2.5% in 20108 (Soil Association 2010:4). On the whole
ideas relating to local and sustainable produce appear to be coming to the fore with
88.3% of households purchasing some form of organic produce (Soil Associaton
2010:4). Organic vegetable box schemes are increasingly popular, in 2009 sales of
them totalled £154.2 million (Edinburgh alone is served by 6 different schemes) and
farmers markets selling fresh, local, produce remain popular (although experienced a
decline during the recession) (Soil Association 2010:13). One study found that
motivations for purchasing organic produce included (Soil Association 2010:8-9):
• A preference for natural/un-processed food
8 Actual figures for 2010 are not yet available.
25
• Restricted use of pesticides
• Better taste
• ‘Better for my well-being’
• Better for the planet
Bread, as previously discussed, is a staple food that most people eat daily (99% of UK
households purchase bread (Espinoza-Orias et al 2011:352)) and the dominant baking
process in the UK is incredibly energy intensive. Arguably the greatest environmental
burden of making bread is the agricultural processes involved in growing the wheat
(Braschkat et al x:12) as this results in the emissions of CO2, N2O and CH4. There is
also the combustion of fossil fuels to power machinery, and in conventional farming
the application of fossil-fuel intensive agro-chemicals.
A number of studies into the carbon footprint of bread have been made, with the
majority focussed on bread making in mainland Europe or North America (Andersson
& Ohlsson 1999; Hansson & Mattsson 1999; Andersson 2000; Braschkat et al 2010
Meisterling et al 2009). Whilst they provide some useful insights into carrying out an
LCA for bread, they are not of direct relevance to this study as they differ in both
farming methods and bread type.
Of direct relevance are a number of studies into British bread (Berners-Lee 2010;
Allied Bakeries 2009; Espinoza-Orias et al 2011) which provide data on the most
regularly consumed bread, allowing for comparisons with bread from the Breadshares
project. Of the most useful is the latter study, as it has examined a number of different
bread scenarios as well as describing the methodology of the study, which provides
the potential for this study to be directly comparable with that carried out by
Espinoza-Orias et al (2011).
In Britain, there are two methodologies for carrying out life cycle assessments. ISO
14044 (2006) is the international standard for LCA’s and governs their application
worldwide. The methodology specific to Britain is the Publicly Available
Specification 2050 “specification for the assessment of the life cycle greenhouse gas
emissions of goods and services” (BSI 2008a, 2008b) created by British Standards
26
Institute and builds on the assessment methods established by ISO 14044 (BSI
2008b:iv).
There are four stages to carrying out a full life cycle assessment (ISO 2006:6):
1. Goal and scope
2. Inventory analysis (LCI)
3. Impact assessment (LCIA)
4. Interpretation of results
ISO 14044 requires that the goal and scope is clearly defined and consistent with the
intended application, although it does allow for refinement during the study (ISO
2006:7). The reasons for carrying out the study, the intended audience of the study
and the use of the results are all required to be defined in the goal (ISO 2006:7), and
for the scope, the system boundary and functional unit, as well as data sources must
be set out (ISO 2006:8-11).
The creation of the inventory analysis requires the accounting for all flows to and
from the product, as defined within the system boundary, and these flows can include
raw materials, energy, greenhouse gas emissions and so forth (ISO 2006:12). This
normally involves the creation of flow charts and data tables, as well as interviewing
external members of the supply chain.
The impact assessment stage involves the evaluation of the environmental impacts of
each of the flows as defined in the inventory analysis (ISO 2006:16-23), with the
impacts being converted in the common equivalence units (e.g. CO2 equivalent).
These are then added together to provide the overall LCA total, or carbon footprint
(ISO 2006).
The interpretation stage normally includes identifying significant issues arising from
the results of the LCI and LCIA stages, as well as evaluating the results for
completeness and consistency. Finally it should include conclusions, limitations and
recommendations based on the results of the LCA (ISO 2006:23).
27
2.2. Methodology
2.2.1 Goal & Scope of the Study
The aim of this study is to provide a calculation (or rather, more accurate estimation)
of the carbon footprint of a loaf of bread produced by the Breadshares Community
Bakery.
The purpose of this study is to evaluate the environmental impact of producing a loaf
of bread in the Bakery, to inform the consumers of these impacts and by comparing
this data with that of an “ordinary” loaf of supermarket bought bread, allowing the
consumer to see the environmental performance offered by organic farming and a
shortened supply chain.
The scope of this study is a business to consumer (B2C) (as defined by PAS 2050), as
the customer is the end point for the bread (BSI 2008b:3) and is similar in scope to a
cradle-to-grave analysis. The study will be PAS 2050 compliant based, where
required, on primary data specific to the Breadshares Community Bakery.
The use of the PAS 2050 methodology was chosen for a number of reasons. Firstly
the only major and accessible study of the carbon footprint of bread in the United
Kingdom (Espinoza-Orias et al 2011) also used the PAS 2050 methodology. This
allows for direct comparisons to be made between different bread.
Secondly PAS 2050 diverges from ISO 14044 in a number of ways which made it
more appropriate for this study given the time constraints.
As per Section 5.5 land use change is only included in the life cycle assessment if the
change took place after the 1st January 1990 (BSI 2008a:9; 2008b:28). This is in line
with the IPCC guidelines that assume that all emissions resulting from land use
change have completed after twenty years.
Emissions resulting from the production of capital goods, such as tools & machinery
are excluded from a life cycle assessment under PAS 2050 methodology (BSI
28
2008a:13; 2008b:32), as there is normally a lack of data for most capital goods, and
such analyses add extra cost and complexity to the LCA (BSI 2008b:32).
Another nuance of PAS 2050 is the inclusion threshold for components of the
functional unit to be included in the LCA. Section 6 states that a source contributing
to less than 1% of the total emissions may be excluded from the LCA, yet the total
proportion of those excluded may not exceed 5% of the total footprint (BSI 2008a:12-
16; 2008b:14). Also excluded are human energy inputs to processes, the transport of
consumers to and from the point of retail purchase and the transport of employees to
and from their normal place of work (BSI 2008a:16).
Unlike ISO 14044, PAS 2050 specifically requires that primary data is used where
possible (BSI 2008a:17) although the requirement does not apply to downstream
emissions (BSI 2008a:17) i.e. those components that are imported into the Bakery
from external suppliers, which in this study would be yeast, water and salt. The
requirement also does not apply when implementing the requirement would involve
physically measuring the GHG emissions (BSI 2008a:17), allowing for the use of
models in calculating the emissions from agricultural processes.
All data collected is converted into emissions data by multiplying the activity by the
specific emission factor for that activity, and is then expressed as per the functional
unit. All emissions then need to be converted into CO2e (carbon dioxide equivalent)
by multiplying by the relevant global warming potential (GWP) figure, as set out in
Table 1.1.
All emissions data is then added together, as per the proportions for the functional
unit in order to give the carbon footprint of the functional unit.
The functional unit for this study as defined by PAS 2050 is an unsliced loaf of bread
weighing 900g (2lbs), made from organic wholewheat flour, produced on a medium
scale and sold for consumption at home. The scope of the study is from ‘cradle-to-
grave’ although the data for the consumption will be based on a previous study
(Espinoza-Orias et al 2011), as explained in Section 2.2.2.4.
29
The functional unit, loaf of bread, is composed of the ingredients and at the
proportions as described in Table 2.1.
Ingredient Weight Proportion of loaf (%) Wholewheat flour 600g 59.23
Salt 5g 0.49 Yeast 8g 0.79 Water 400g 39.49
Table 2.1: Ingredients of a Breadshares Bakery loaf
As defined by PAS 2050 (BSI 2008b) the functional unit and scope of the study are
suitable for carbon labelling the product and communicating with the consumer.
2.2.2 System Boundaries
The following stages & processes are included within the system boundary, using the
stages set out by PAS 2050 (BSI 2008b:11):
1. Raw Materials
a. Farming: Cultivation, harvesting, drying and storage of grain
b. Other ingredients from external suppliers: water, salt & yeast
2. Processing
a. Wheat milled into flour
b. Ingredients mixed, proved, baked and cooled
3. Retail/Distribution
a. Storage of bread at ambient temperature in farm shop – daily
b. Possibility of distribution via van to customers in Edinburgh
4. Consumption
a. Bread stored at room temperature, refrigerated or frozen
b. Bread consumed either as is, or toasted
5. Waste Management
a. Disposal of bread & any packaging
30
2.2.2.1 Raw Materials
Farming includes all the processes required for the cultivation of the organic wheat,
harvesting, drying and storage. The wheat is to be grown (following a two year trial)
onsite at Whitmuir Farm, using a 6 year rotation cycle of 1 year pig grazing, 3 years
grass/clover cover and 2 years of wheat. In the two year trial, it was found that pigs
and clover provided enough nutrients to enable a successful crop yield for one year
(with a protein content of 13%), although a second was not evaluated. Field
operations including ploughing, seed distribution and harvesting are carried out using
machinery. At Whitmuir Farm, the land has been used for agriculture since before
1990 and thus the GHG emissions arising from land use change do not need to be
considered.
The other ingredients used to make the bread are yeast, salt and water. Water is
currently taken from the domestic water supply provided by Scottish Water, although
there is scope to eventually extract water from a burn on the farm. The yeast and salt
are purchased from downstream manufacturers.
Initially, the bread will be sold direct to consumers onsite via the Whitmuir Farmshop,
meaning that no packaging is required for the produce. However there are preliminary
plans for the eventual implementation of a distribution system. This would be similar
to vegetable box schemes, with a van delivering loaves to customer’s homes in
Edinburgh and the Lothians a number of times a week. This would require packaging
in order to keep the bread covered during transportation, most likely in the form of
paper bags, although it is not inconceivable that a re-usable fabric bag could also be
used.
2.2.2.2 Processing
The first stage of processing is milling the harvested and dried wheat into flour. This
process uses a fairly small electric grain mill that turns a pair of millstones to produce
between 75kg to 100kg of flour an hour.
31
The extraction rate of the wheat, defines the type of flour produced (Espinoza-Orias et
al 2011:354). A 75% rate produces white flour, 85% rate produces brown flour and
100% (meaning all of the grain is included in the flour) produces wholewheat flour
(Espinoza-Orias et al 2011:354). It is this last type that will be used for the
Breadshares flour.
The second stage of processing is the preparation of the dough by mixing the
ingredients and then kneading. This is all carried out by hand, with the dough being
left to prove (rise) naturally for a couple of hours.
The final stage is baking. This is carried out in an electric powered oven, although a
wood fired oven was also initially considered. The oven initially uses energy to heat
up to the required temperature; once at that, no more power is required as it is
sufficiently well insulated to allow it to retain heat for a prolonged period. Over time,
some heat does dissipate; although the temperature of the oven never drops down by a
great amount, meaning that less energy is required to reheat the oven to baking
temperatures.
Whitmuir Farm has just installed a 50kw wind turbine, and it is hoped that this will
provide sufficient power to the mill, oven and shop (at different times), although due
to the unpredictability of nature, it is expected that there will be periods when power
demand will exceed the generation capacity.
To this end it was decided to calculate three carbon footprints based on different
electricity mixes, which should provide enough data to efficiently cover all
eventualities.
Scenario A. 100% on-site renewable
Scenario B. 50/50 on-site renewable/grid
Scenario C. 100% grid
2.2.2.3 Retail
The finished loaves will be sold in the existing Whitmuir Farm shop; stored at an
ambient temperature and sold on the same day as baking. As this utilises existing
32
premises and has no additional energy demands, it is assumed that this stage does not
contribute anything to the product’s carbon footprint.
There are proposals to implement a delivery scheme across Edinburgh and the
Lothians for the Breadshares Bakery bread, although this is not included in the system
boundary.
2.2.2.4 Consumption
As no first hand data is available for the methods of consumption of the Breadshares
Bakery bread, the consumption pattern data is based on that of Espinoza-Orias et al
(2011).
Product Category Rules (PCR) set by the Carbon Trust were used in the study by
Espinoza-Orias et al (2011:354), and are also used here. They state that in the home,
61% of bread is eaten as is, with 39% being toasted; 72% of bread is stored at ambient
temperature with 20% frozen for over 10 days, and 8% chilled for 4 days.
However for this study it is assumed that all bread is stored at ambient temperature
with 39% of the loaf being toasted.
2.2.2.5 Waste Management
Again the amount of bread wasted by the consumer is unknown. Studies suggest that
up to 30% of food in the UK is wasted (WRAP 2008; Williams & Wikström 2011)
although this does include inedible parts of food such as bone. Due to the
demographic of purchasers of organic produce, it is thought that the consumers of
Breadshares Bakery bread would waste something closer to the region of less than
10% of the bread. Further more it is expected that any wastage incurred by the
consumer would not end up in landfill but would instead be used as bird feed and the
like.
33
2.3 Data Sources
As previously discussed PAS 2050 requires that primary data be used “for all
processes and materials owned, operated or controlled by the footprinting
organistaion” (BSI 2008b:17). In this project the requirement for primary data covers:
• Cultivation of wheat
• Milling
• Baking
Secondary data will be used for:
• GWP data
• Production of yeast
• Production of salt
• Production/distribution of water
• Electricity generated off-site
• Consumption
o Chilled and frozen storage
o Toasting
As also mentioned in clause 7.3, primary data is not required if it would necessitate
physically measuring GHG emissions (BSI 2008a:17), therefore emissions generated
during the cultivation of the wheat can be calculated using a carbon footprinting
model for agriculture.
For this stage a number of different models were evaluated. One developed by the
Scottish Agricultural College (not publicly available) and currently in beta mode, and
one, AgriLCA9, developed by the Silsoe Research Institute at Nuffield University as
part of the Defra Project IS0205 (Williams et al 2006; Williams et al 2010) into the
environmental burdens of agriculture.
AgriLCA was chosen as it was designed specifically for modelling emissions from
crops, rather than the whole farm scenario modelling carried out by the SAC model. It
9 https://webapps2.cranfield.ac.uk/webforms/form.jsp?formId=12024
34
was therefore able to be specifically tweaked to fit the agricultural methods used to
grow the wheat at Whitmuir Farm.
Primary data on milling and baking was supplied by members of the Breadshares
Bakery.
All secondary data satisfies the PAS 2050 criteria (BSI 2008b:19) that it should be
sourced from peer-reviewed publications, government publications and official UN
publications where possible.
35
2.4 Results
The results here are set out in the order as defined in section 2.1.
2.4.1 Life Cycle Inventory
The Figures below set out the energy flows for the life cycle of a Breadshares loaf of
bread; Figure 2.1 shows the overall flows, whereas Figures 2.2 & 2.3 show the energy
flows for specific components of the life cycle.
36
Figure 2.1 Energy flows for ‘cradle-to-grave’ analysis of Breadshares loaf
37
Figure 2.2 Detailed energy flows for the Raw Materials stage
Figure 2.3 Detailed energy flows for Processing stage
38
2.4.2 Life Cycle Inventory Analysis
2.4.2.1 Raw Materials
The AgriLCA was utilised to model the emissions generated during the cultivation,
harvesting and drying/storage stage of the wheat. The results are presented in Table
2.2.
Impacts & resources used
Organic Primary Energy used, GJ 1.38 Global Warming Pot'l, t (100 year) CO2 Equiv. 0.40 Distribution of GWP by gas CO2 26% CH4 0% N2O (direct) 57% N2O (secondary and other gases, e.g. CO) 17%
Table 2.2 Emission results for the organic wheat
The cultivation, harvest and storage of one tonne of organic wheat generates 0.40
tCO2e in emissions; which equates to 0.4kgCO2e emissions for 1kg of wheat.
The wheat is then milled into flour. The mill used can produce between 75kg and
120kg of flour an hour, and has a power rating of 6.25kWh. Using the conservative
yield value of 100kg, 1kg of milled flour has a power consumption of 0.0625kWh. In
Scotland the average emission factor for 1kWh of electricity is 0.362 kgCO2e (The
Scottish Government 2011)
For the different electricity supply scenarios listed above, the emissions for milling 1
kg of flour are as follows:
Scenario A. 0 kgCO2e
Scenario B. 0.01131 kgCO2e
Scenario C. 0.02262 kgCO2e
39
Therefore 1kg of wholewheat flour has a carbon footprint of:
Scenario A. 0.4 kgCO2e
Scenario B. 0.41131 kgCO2e
Scenario C. 0.42262 kgCO2e
No emissions data is available for the yeast used in the baking process, in fact it is
very difficult to find a figure for the carbon footprint of yeast anywhere, and is
something being addressed by a major study launched in 2010 (COFALEC 2010).
Instead a value was obtained from the Simapro 6.0 database; this provided a carbon
figure of -0.0556kgCO2e per kilogram of yeast.
The value is negative as Simapro calculates the sugar beets used in yeast production
absorb more CO2 from the atmosphere than is emitted during their cultivation
(Bimpeh et al 2006:12).
The emissions data for the salt was also obtained from the Simapro 6.0 database; this
gave a value of 0.167kgCO2e per kilogram of salt used.
Scottish Water (2010) have calculated that the carbon footprint of supplying one litre
of water to be 1.5x10-4 kgCO2e (Scottish Water 2010:6).
Ingredient Weight (kg)
Emissions per kg (kgC02e)
Emissions (kgCO2e)
Wholewheat flour Scenario A 0.6 0.4 0.24 Wholewheat flour Scenario B 0.6 0.41131 0.246786 Wholewheat flour Scenario C 0.6 0.42262 0.253572
Yeast 0.08 -0.0556 -0.004448 Salt 0.05 0.167 0.00835
Water 0.4 1.5x10-4 6.0×10-5 Total Scenario A 0.243962 Total Scenario B 0.250748 Total Scenario C 0.257534
Table 2.3 Carbon footprint of each raw material
40
2.4.2.2 Processing
Conservative values for the power consumption per loaf for the baking stage give a
value of 0.180kWh per loaf. Using the emission factor of 0.362 kgCO2e (The Scottish
Government 2011) per kW of electricity give the following emissions for each
scenario:
Scenario A. 0 kgCO2e per loaf
Scenario B. 0.03258 kgCO2e per loaf
Scenario C. 0.06516 kg CO2e per loaf
2.4.2.3 Consumption
Espinoza-Orias (2011:357) calculated that the power consumption for toasting a slice
(40g) of wholewheat bread is 0.047kWh, which gives emissions of 0.01701 kgCO2e
per 40g slice of bread (assuming that all electricity used in the consumption phase is
the Scottish average).
Since the assumption is that 39% of the loaf is toasted, this equates to 351g of bread
or 8.775 slices, giving a total of 0.1493 kgCO2e emissions for the consumption stage.
2.4.2.4 Loaf Carbon Footprint Total
Stage Scenario A Scenario B Scenario C Raw Materials
0.243962 0.250748 0.257534
Processing 0 0.03258 0.06516 Consumption 0.1493 0.1493 0.1493
Total= 0.393262 kgCO2e per loaf
0.432628 kgCO2e per loaf
0.471994 kgCO2e per loaf
Table 2.4 Carbon footprint of a loaf under each scenario
41
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
Scenario A Scenario B Scenario C
kgC
0 2e Consumption
ProcessingRaw Materials
Figure 2.4 Breakdown of the 3 carbon footprints
2.4.3 Results Analysis
The carbon footprint of a loaf of bread baked by the Breadshares Bakery ranges from
0.39kgCO2e to 0.47kgCO2e depending on the mix of electricity used; for each
scenario, the raw materials accounted for the largest share of the footprint, although in
Scenario C, the processing & consumption stages combined almost matched the raw
materials for emissions.
In all scenarios the raw materials obtained from downstream sources contribute less
than 4% to the carbon footprint, and this contribution may be even less if primary data
was available for the salt and yeast.
In all three scenarios, the cultivation of the wheat accounts for the greatest CO2e
emissions; although the use of grid electricity in the consumption stage accounts for
30% or greater of emissions in all Scenarios.
42
Scenario A
60%
0%
1%
2%
0%
0%
37%Wheat CultivationWheat MillingYeastSaltWaterBakingConsumption
Figure 2.5 Breakdown of carbon footprint for Scenario A loaf
Under Scenario A, where all the electricity used in the production of the loaf is
generated from the on farm wind turbine, the consumption stage accounts for over a
third of the carbon footprint. This is also a stage that the producers have no control
over which cannot be lowered aside from encouraging consumers to switch to
renewable energy suppliers.
43
Scenario B
54%
2%1%
2%
0%
7%
34%
Wheat CultivationWheat MillingYeastSaltWaterBakingConsumption
Figure 2.6 Breakdown of carbon footprint for Scenario B loaf
In Scenario B, where a 50/50 mix of onsite generation and ‘standard’ electricity was
used, the wheat cultivation still emits the majority of emissions per stage. However
when the electricity use (milling, baking and consumption) is added together, it
accounts for 43% of emissions.
44
Scenario C
49%
3%1%
2%
0%
14%
31%
Wheat CultivationWheat MillingYeastSaltWaterBakingConsumption
Figure 2.7 Breakdown of carbon footprint for Scenario C loaf
The use of 100% grid electricity sees a change is the breakdown of the carbon
footprint. Wheat cultivation still remains the single largest emitter by process; but
overall electricity consumption now accounts for 48% of the emissions from a loaf of
bread. The contribution of milling to emissions increases to 3% of the total with
baking contributing to 14% of the total emissions.
45
2.5 Discussion
In all three scenarios (Table 2.5), the Breadshares loaf has a lower carbon footprint
than any other UK loaf (where data has been published), and is similar to studies on
the continent (Andersson & Ohlsson 1999; Braschkat et al; Williams & Wikstrom
2011). Although it should be noted that bread on the continent is of a different style
and form to UK bread and is thus not a suitable comparison for the Breadshares bread.
Product
Carbon Footprint (kgCO2e) Scenario
A Scenario
B Scenario
C Espinoza-
Orias (2011)
PAS 2050
Espinoza-Orias (2011)
Generic
Allied Bakery (2009)
White - - - 1.20 1.07 1.3 Wholewheat 0.39 0.43 0.47 1.16 1.00 1.3
Brown - - - 1.03 1.2 Table 2.5 Comparison of the carbon footprints of different breads in different studies
Bread baked under Scenario A, which is the primary method used by the Breadshares
Bakery, has a carbon footprint less than half that of any other study, and is less than a
third of the Allied Bakery wholewheat loaf.
Bread baked under Scenario C, using 100% grid electricity has a carbon footprint that
is still less than half of any other study, and just over a third of the Allied Bakery
wholewheat loaf.
Life Cycle Stage
% Contribution Scenario
A Scenario
B Scenario
C Espinoza-
Orias (2011) PAS 2050
Espinoza-Orias (2011)
Generic
Allied Bakery (2009)
Raw Materials 63 59 55 41 45 45 Wheat Cultivation 60 54 49 35 32
Wheat Milling 2 3 3 5 Ingredients 3 3 3 19 12
Processing 7 14 16 7 21 Packaging 1 4 2 Transport 4 5 4 Retail 4 2 2 Consumption 37 34 31 25 26 23 Waste Management 6 6 3
Table 2.6 Relative contribution of the life cycle stages to the carbon footprint of the breads
46
As can be seen from Table 2.6 most of the Breadshares bread lifecycle stage
contributions are broadly similar to those identified in other studies. Scenario A is the
anomaly since it has no emissions from electricity use, meaning that the wheat
cultivation is a much larger proportion of the overall emissions.
Packaging, transport, retail and waste management account for roughly 15% of the
carbon footprint of the other bread types, equating to, on average, 170gCO2e of
emissions. If such a value were to be incorporated into the carbon footprints
calculated in this study, then the Breadshares bread would still outperform any of the
other UK breads, although Scenario C bread would be within with 0.25kgCO2e of the
wholewheat, thick sliced bread calculated under the generic study (Espinoza-Orias
2011:360).
The emissions generated during the wheat cultivation (0.4tCO2e per tonne) are half of
those calculated for organic wheat (0.8tCO2e per tonne) by Williams et al (2010:864).
The savings here can be attributed to 0.62GJ less energy use in the cultivation of the
Breadshares wheat, as well as the lack of mineral fertiliser used in the cultivation and
the exclusion of capital goods from the study.
The life cycle analysis has shown that in all three studies, a hot spot for emissions is
the consumption stage (toasting), which creates 0.149kgCO2e emissions. The carbon
footprint could be lowered by between 31% and 37% if consumers were encouraged
not to toast their bread, or to switch to a greener electricity source, although this is not
an area that the producers can have a direct influence over.
The hotspots identified in this study, wheat cultivation and consumption, are the same
as those identified by Espinoza-Orias et al (2011).
The oven used during the processing stage contributes to reducing the emissions per
loaf of bread. If a standard method of baking were to be used, whereby the oven is
heated up to the required temperature and is then maintained at that temperature until
it is switched off at the end of the baking day, the power consumption per loaf of
bread would be around 0.601kWh, over three times that required by a Breadshares
47
loaf. In terms of emissions, using the three scenarios the baking stage (using a generic
oven) would account for:
Scenario A: 0 kgCO2e per loaf
Scenario B: 0.1088 kgCO2e per loaf
Scenario C: 0.2176 kgCO2e per loaf
Thus by using a well insulated oven, carbon savings of up to 0.15 kgCO2e per loaf,
around one third of the total emissions for a loaf, are made.
If the proposed delivery scheme to the Edinburgh & Lothians region was
implemented, then around 0.218kgCO2e would be added to a delivered loaf of bread.
This is composed of an estimated 0.206kgCO2e for a 44 mile round trip for the
delivery van, and 0.012kgCO2 (Berners-Lee 2010:21) for a recycled paper bag.
Whilst adding on up to two thirds to the carbon footprint, a loaf of Breadshares Bread
would still outperform any of the other loaves.
Opportunities for reducing the use of farm diesel, which accounts for the majority of
the primary energy use in the wheat cultivation, and thus reducing the cultivation
stage emissions, are limited.
This study demonstrates the environmental benefits of a localised food production
system using organic wheat, and an on-site generated renewable electricity source
where possible. Both Scenarios B & C show that using grid electricity can add up to
230gCO2e emissions to the product, yet even so they still outperform any other bread.
48
Chapter 3: Food, Farming and Sustainability
3.1 Introduction
As has been seen, the growing of wheat organically i.e. without the use of
agrochemicals and following the standards set by the Soil Association, in addition to
cutting down on the distance the product has to travel has a dramatic effect on
reducing the carbon footprint of a loaf of bread. What implications then, does this
have on ideas of sustainability, farming and food?
Firstly we will look at energy use in agriculture. As peak oil becomes a greater issue,
will this force a change in the way that agriculture is carried out?
Secondly organic farming will be compared to conventional farming. We have
already seen that organic practices can reduce GHG emissions associated with
agriculture, but is there scope for this to be done in conventional farming as well?
What other benefits does organic farming provide over conventional farming? Are
there any disadvantages?
Thirdly the concept of local food and food miles will be examined. As ideas of green
living have entered every day life, many people have turned to local food, which
which travels much less distance, as more sustainable than produce that is imported
from around the world. Is this actually a correct view of the global food system? Are
food miles the best indicator of this?
As discussed in Section 1.3 the way that food is processed, prepared and
manufactured can include many additives and ingredients that take away from the
nutritional value of the food. For further information on the concept of food and well-
being and to examine links between increases in allergies and other dietary problems
& highly processed food there is a wealth of literature. Of particular interest are
publications by The Soil Association (2003), Whitley (2009), Jiang et al (2010) and
Block et al (2011).
49
3.2 Energy Use in Agriculture and Peak Oil
The world wide demand for oil reached a peak in 2010 with 87.4 million barrels a day
being consumed (BP 2011:9). This is a 1.9million barrel increase on the previous
global peak of 85.6m in 2007 (BP 2011:9), which had been followed by two years of
declining consumption due to rising prices (BP 2010:16). It should, however, be noted
that oil consumption in the UK has been in a steady decline since 2005 (1.8m barrels
per day to 1.6m barrels per day) (BP 2011:9).
Whilst the vast majority of the UKs consumption is accounted for by transportation, a
significant amount is also used in agriculture (1.86% of total UK energy use) (White
2007:105). Of this 30% is direct energy use, with the remaining 70% resulting from
indirect energy use (White 2007:105).
Direct energy use is the consumption of fuel in the operation of agricultural
machinery and equipment, as well as electricity and gas use for heating greenhouses,
drying crops and lighting and heating other buildings (Arizpe et al 2011:23). Indirect
energy use relates to the energy consumed in the production of technological inputs
such as capital goods (machinery & equipment) as well as agro-chemicals such as
pesticides and fertilisers (Arizpe et al 2011:23-4).
The carbon savings identified in this study are mainly made in the indirect energy use
category, as organic farming eschews the use of fertilisers & pesticides, thus reducing,
to an extent, the reliance of agriculture on oil, which is something that could become
key in the future.
Agro-chemicals (pesticides and fertilisers) are currently synthesised from fossil fuels
(Heinberg 2005:197). Nitrogen fertiliser in the form of ammonia is created through
the Haber-Bosch process which uses an estimated 10GW (Madrigal 2008) of gas,
accounting for around 1% of global energy consumption, to break the triple bond
structure of atmospheric nitrogen and form ammonia. It takes one tonne of oil and 108
tonnes of water to produce one tonne of nitrogen fertiliser, whilst emitting 7 tonnes of
carbon dioxide equivalent GHGs in the process (Soil Association 2008:7-8). Fertiliser
50
created through the Haber-Bosch process is thought to have helped grow 40% of the
worlds food supply.
In 2002, the USA used 0.6 exajoules worth of fertiliser and pesticides (Schnepf
2004:5) which was equivalent to the entire energy use of Mexico. Whilst this is not
comparable to the UK, what is clear is the high dependency that agriculture has on oil
in order to provide the yields, and thus the food security that the developed world has
come to enjoy (Arizpe et al 2011).
Figure 3.1 Primary energy use in agriculture 1971-1995 (From Woods et al 2010:2992).
Light blue line, total fertilizers per ha cropland; brown line, cereal yield;
purple line, total area equipped for irrigation; green line, tractors per ha;
dark blue line, agricultural labour per ha cropland.
The concept of peak oil was first introduced by Paul Hubbert in 1956 (Heinberg
2005:97). He observed that oil production follows a bell curve; initially production is
low during the discovery phase, but as time passes more wells are dug, increasing
production (Heinberg 2005:97). After a certain point; ‘the peak’, the reserves are
harder to access and production declines. This normally occurs when half of the oil
reserve has been drained and the oil becomes increasingly hard to reach. Due to
impracticalities an oil reserve is never completely emptied, as extracting the last
amounts is both prohibitively high in cost and more often than not impossible
(Heinberg 2005:98).
51
Figure 3.2 Hubbert’s bell curves for global peak oil (From Heinberg 2005:99)
Hubbert predicted that the peak in US production would occur between 1966 and
1972, it occurred in 1970.He also predicted that the global peak would occur between
1990 and 2000 (Figure 3.2) (Heinberg 2005:97-8) however this latter prediction was
not realised as advances in technology allowed for oil fields to be more accurately
updated (Heinberg 2005:98). There is no clear consensus on when the peak will
occur, with recent predictions (Table 3.1) covering a time span of only 30 years
(Leggett 2007:9).
Year Author 2005 Kenneth Deffeyes 2006 Henry Groppe 2007 Ali Samsam Bakhtiari 2007 Richard Duncan 2007 ODAC 2010 Colin Campbell 2013 Rembrandt Koppelaar 2015 Jean Laherrere 2015 PFC Energy 2020 CERA 2030 USGS
Table 3.1 Studies suggesting peak oil dates (Leggett 2007:9)
Matt Simons (2006) has suggested that the global peak will occur when Saudi Arabia
reaches its peak, as it is the possessor of the world’s spare production capacity.
52
Some have argued that even when we reach what we believe to be peak oil, this will
not present a challenge as there are a few trillion barrels of oil waiting to be
discovered in reserves not yet found (Leggett 2007: 9). This claim however is
disputed by a small, but growing, number of analysts who reckon that the amount left
is below 1 trillion and these are in reserves that will be very difficult to locate and
extract from (Leggett 2007:9).
What is clear is that whilst we do not know quite when the peak will occur, if it has
not already passed, we are expecting it to happen relatively soon, and this has many
implications for the future.
In order to try and reduce our dependence on crude oil, one solution that has been
developed by various governments worldwide is that of biofuels. These are crops such
as switchgrass and corn that are grown specifically to be turned into biofuels (Roberts
2004:79) such as ethanol (Heinberg 2005:174) which can then be used to power
engines as a replacement to petrol and diesel.
Whilst biofuels are an attractive alternative when oil prices are high, they are a
significant drain on arable land (Monbiot 2004; Heinberg 2005:175). Calculations
show that in the UK one hectare of arable land can provide 1.45 tonnes of transport
biofuel a year (Monbiot 2004). Given that the UK transport sector consumes
37.6million tonnes of fuel a year, 25.9 million hectares would be required to supply
the fuel demand (Monbiot 2004). The UK currently has 5.7 million ha of arable land,
so in order to fulfil a 100% biofuel target, 5 times this would be required to satisfy the
demand. To even reach the European Union target of a minimum of 10% of fuel from
biofuels by 2020 (EU 2007) would require around half of the UK’s current arable
land, and this has worrying implications for food supply and food security.
In 2007 a quarter of the USA’s corn harvest was diverted to biofuel production
(Kingsbury 2007) and this is a pattern that can be seen in many countries globally.
This reduces the availability of food around the world in order to satisfy a largely
impractical green policy. What this does is to reduce a country’s ability to feed itself,
making them more reliant on food imports, and thus more susceptible to rises in food
53
prices. In 2008 food prices rose dramatically (Figure 3.3), due to poor harvests, an
increase in biofuel production and a lack of exports. Wheat increased in price by
130% (BBC 2008) and this had the knock-on effect of causing food riots around the
world (The Times 2008).It also had the consequence that countries, who are normally
exporters of grain, to halt exports in order to supply their domestic market, further
increasing the price of food.
Figure 3.3 Energy and food prices 1992-2008 (From BBC 2008)
As a side note, the environmental impacts of biofuel should be mentioned.
Commentators still disagree over the energy balance of biofuel (Heinberg 2005), a
recent study published in Science (Fargione et al 2008; Searchinger et al 2008) found
that many studies in favour of biofuels that highlight their value as a climate change
mitigation tool, failed to take into account the impact of land use change (as forestry
is cleared to increase the land available to grow biofuel crops). When this factor was
included in evaluations, corn ethanol and soy biodiesel have twice the emissions of
petroleum products (Fargione et al 2008; Grunwald 2008).
It is plain to see that the increase in yield experiences from the middle of the 20th
century onwards is mostly due to the high energy inputs that fossil fuels provide
(Arizpe et al 2011). The global food supply is now dependent on oil in order to
continue feeding the growing global population.
Once we reach peak oil and supplies start to decline, it is likely that prices will rise,
and that restrictions will be placed on the use of oil. Then, as Heinberg says “it is not
difficult to imagine the likely agricultural consequences” (2005:196).
54
Initially food prices would rise (Woods et al 2010:2998; Arizpe et al 2011:21) which
would most likely be followed by food shortages that could be Malthusian in their
nature (indeed it was advances in technology during the Green Revolution that largely
prevented Malthus’ theory happening). This could bring about a massive decrease in
population (Heinberg 2005; Soil Association 2007; Arizpe et al 2011), although this
is worst case scenario.
In order to weather a future of declining oil supplies, it is clear that agriculture needs
to de-energise as much as possible. Whilst some savings can be made in direct energy
use; machinery can be made more fuel efficient and used a little less and renewable
energy sources can be used to power infrastructure such as dryers, greenhouses and
building, we cannot scrap the use of machinery altogether, whilst maintaining an
adequate food supply.
In 1900 40% of the UK’s population was employed in agriculture, this figure has now
declined to less than 1% in the present day (Heinberg 2007:14). The number who
once would have been employed in agriculture are now employed in other sectors of
the economy; with 50% of the UK population living in urban areas, it would require a
major shift in the structure of the UK demographics and economy to increase the
number of workers in agriculture to an extent where machinery use could be
dramatically reduced, and this is a largely impossible task (Heinberg 2007).
Where significant savings can be made is in indirect energy consumption. This would
require a shift away from chemical fertilisers and pesticides to pre-1950s farming
methods when “farming was almost exclusively a solar industry” (Pimentel &
Giampietro 1994). Studies of energy use within agriculture suggest that the adoption
of organic farming practices provide a significant energy reduction (Amate & de
Molina 1011; Gomiero et al 2011). A report for the Danish Government (Hansen et al
2001) found that a 100% adoption of organic methods would reduce agricultural
energy use by 9-51% depending on certain parameters. It has been argued that yields
provided by organic farming are lower than those from conventional farming
(Gomiero et al 2011) whilst other studies have found yields to be comparable (Clark
et al 1999; Pimentel et al 2005). If yields did decrease, an expansion of agricultural
55
lands would be possible in most countries, although this would have implications of
increased GHG emissions from land use change.
Alternatively a shift in diet could provide the answer. At the moment around half of
all grain is diverted for animal feed (Goodland 1997:195) where is it inefficiently
used to produce meat for “the minority higher-income sectors of society” (FAO 1995;
Goodland 1997:195). A shift in diet away from meat, towards a more grain based one
would allow greater amounts of grain to be used for human consumption, reducing
concerns relating to organic farming yields and increasing food security.
Finally, peak oil will have an impact on travel and transportation; limited oil would
restrict the ability to transport food produce by road and air, although it is likely that
there would be limited trade utilising rail and canals (Hopkins 2007:19). This could
force a shift back towards localised agriculture and food systems, which are explored
further in Section 3.4.
56
3.3 Conventional and Organic Farming: a Comparison
Here the term ‘conventional farming’ refers to the farming method that uses agro-
chemicals such as fertilisers and pesticides, and in developed countries has become
increasingly intensive, extensive and monoculture. The vast majority of farming in the
UK is conventional.
Organic farming on the other hand eschews the use of chemicals; it is “a holistic
production management system that avoids the use of synthetic fertilisers, pesticides
and genetically modified organisms, minimises pollution of air, soil and water, and
optimises the health and productivity of interdependent communities of plants,
animals and people” (Scialabba & Müller-Ludenlauf 2010:159). In the EU organic
produce labelled organic must satisfy certain criteria in order to obtain its certification
(Scialabba & Müller-Ludenlauf 2010; Gomiero et al 2011:99), with produce only
being allowed to be sold as organic if at least 95% of the ingredients are organic.
Those who farm organically often do so to preserve the natural environment, amid
concerns that conventional farming can have a negative impact upon the flora, fauna
and ecosystem services of an area as well as on resources such as soil fertility and
water quality; these issues are discussed later in this section.
Of particular concern with regards to conventional farming is the large scale use of
agro-chemicals, as well as the creation of mega-fields through the removal of
hedgerows and other boundary features. This in addition to the fact that most farms
concentrate on single crop species in an area can have a negative impact on the
biodiversity of a region.
It is estimated that in the UK 300kg of N are applied per hectare per year (Conway &
Pretty 1991:159), in conventional farming. Theoretically around 90% of applied
fertiliser can be recovered by the plants and soil; however the actual figure is
normally between 20 and 70% (Conway & Pretty 1991:212) with the lost fertiliser
becoming a pollutant.
Fertiliser lost through run off can end up in water bodies such as rivers, lakes and
streams. Here it causes eutrophication and results in a number of issues within the
57
water (Skinner et al 1996:119). At first growth amongst aquatic species of flora is
promoted, especially of algal species which are highly responsive to nitrogen and
phosphorus. This results in a dense bloom that causes the death of other aquatic
species in a number of ways (Skinner et al 1996:119). The bloom starves other
species of light and then eventually the algae sinks to the bottom of the water body.
As it decays it creates anoxic conditions, which can lead to a rapid decline in resident
species.
There are a number of environmental and economic implications related to the
eutrophication of terrestrial waters as identified by the FAO (FAO 1996):
• Shift in habitat characteristics due to change in aquatic plants
• Loss of desirable species of fish e.g. salmon
• Production of toxins by certain algae
• Loss of recreational use of water due to slime, weed infestation and noxious odour
Fertiliser can also affect domestic water supplies; algal blooms can block water
treatment plants and leave undesirable odours and tastes in drinking water (Conway &
Pretty 1991:198, Skinner et al 1996:120). Nitrates can also leach through the soil into
groundwater supplies, although the full extent is not known as transition time through
the underlying geology can be up to 40 years (Conway & Pretty 1991:183). Thus
fertiliser can cause a considerable increase in the costs of treating water supplies
(Skinner et al 1996:119, Pretty et al 2000:117).
As can be expected the impacts of pesticides on the environment are much higher than
those of fertilisers. The inherent flaw of pesticides is that they are indiscriminate by
nature; they may be designed to attack certain pests by targeting specific
characteristics but will also attack anything else with the same characteristics
(Conway & Pretty 1991:24). It has been calculated that only about 5% of the applied
pesticide reaches the intended organism (Miller 2009:149), with the remainder
entering the environment as a pollutant. Such losses can have significant impacts
upon the environment, particularly on local flora and fauna, which will briefly be
outlined below.
58
In the wider environment pesticides can move into the atmosphere and can be
redeposited though rainfall far away from the site of their application. Contamination
of surface water through runoff is relatively rare in the United Kingdom, although it
can occur after periods of heavy rain (PAN 2010:11). Pollution from point sources is
more common (Skinner et al 1996:113), and instances of this are dealt with under UK
legislation. Leaching through soils into groundwater supplies does also occur,
requiring extensive and expensive treatment for domestic supplies, it has been
estimated that such treatment costs annually around £140m in the UK alone (Pretty et
al 2000:117).It is widely documented that the use of pesticides has had significant
impacts upon the biodiversity of areas where they are applied (Moore 1967). Not only
do pesticides remove the weeds which are the first link in the food chain for many
species (PAN 2010:3) but they can also be ingested through the eating of treated
plants, causing poisoning within animals.
Between 1990 and 2006 the area of British farmland treated with pesticides rose by
38% (Fera 2009) but diversity of plant species found within fields declined (PAN
2010:12). This has been attributed to both the use of pesticides but also other changes
in agriculture such as the removal of hedgerows.
Soil fertility is also affected by pesticides; studies have shown that pesticides can
remove nitrates from the soil and they can also reduce the number of earthworms
within the soil (PAN 2010:13). This is a catch 22 situation for farmers who have to
apply more fertiliser to compensate for the decrease in soil fertility.
Faunal species can also be directly poisoned by the spraying of pesticides over crops.
Some 10m breeding individuals of ten species of farmland bird have disappeared
between 1979 and 1999 (Krebs et al 1999:411), with farmland bird populations
falling by 51% between 1970 and 2007 (DEFRA 2009:57). The deaths of other
animals have also been attributed both directly and indirectly to the spraying of
pesticides (Skinner et al 1996:115, Conway & Pretty 1991, Chadwick 1993, Boatmen
et al 2004, PAN 2010).
One of the most notable species whose decline in recent years has been attributed to
pesticides is that of the honey bee (PAN 2010:9). In the UK between 1995 and 2001,
59
85% of reported bee poisonings were caused by pesticides (PAN 2010:9), with further
estimates that modern farming practices are responsible for the loss of ca. 2000
colonies a year (Pretty et al 2000:127). Research has also demonstrated that pesticides
have altered the behaviour of honey bees (Decourtye et al 2003).
Since organic farming does not make use of chemical fertilisers and pesticides, none
of the issues presented above occur on organic farms.
Without chemical pest (insect and weed) control, these can become an issue on
organic farms (Gomiero et al 2011:97). Zhu et al (2000) have argued that with
increasing intensification and monoculture, crops vulnerability to pests and disease
increases. Therefore by increasing biodiversity & habitats (common in organic
agriculture), natural pest control can compensate for the lack of chemical pesticides
(Gomiero et al 2011:108). It has been shown that organically managed soils enhance
the nutrient balance in plants, which can increase resilience to pest attack (Phelan et al
1996; Alyokhin et al 2005; Gomiero et al 2011). The increasing abundance of birds
on organic farms can also provide weed and pest containment (Westerman et al
2003); studies in the Netherlands (Mols & Visser 2002) found that the introduction of
the Parus major L to apple orchards reduced the number of pest caterpillars by up to
99%, increasing yields from 4.7kg to 7.8kg per tree.
It would be reasonable to suggest that a reduction in the use of pesticides that is
accompanied by a rise in biodiversity would also experience a rise in the number of
pests; this is not always the case. Pesticides can disrupt the natural predators of pests,
allowing pest numbers to increase unchecked (if they develop resistance to the
chemicals). When pesticide use is stopped, this allows for natural pest control to re-
develop and a number of studies have shown no increase in organic yield losses to
pests (Gomiero et al 2011:109), although it should be noted that introducing non-
native species as pest control is not recommended as they can become invasive
species themselves (Thomas & Reid 2007).
Weeds can remain an issue; studies in Scotland (Hawesa et al 2010) found
significantly greater numbers of weeds on organic farms and this is a trend found
worldwide (Hole et al 2005:115). Whilst birds (see above) can be used for weed
60
control, many organic farmers result to either manual weed clearing (significantly
increasing the number or workers required) or flame weeding (significantly increasing
the fuel consumption of the farm), with the latter generating substantial amounts of
GHG’s.
The majority of studies into biodiversity (number of species & species numbers) and
agriculture have found that it is greatly enhanced on organic farms when compared
with conventional farms (Hole et al 2005; Gomiero et al 2011:106). Of 65 studies
analysed by Bengtsson et al (2005), 53 (84%) found enhanced biodiversity, although
a number of authors have suggested that carefully managed conventional agriculture
could achieve similar results (Gibson et al 2007).
In terms of numbers, organic farms have been found to have 74-153% more weed
species compared to conventional farms, as well as, 68-105% more spiders, 16-62%
more birds and 6-75% more bats (Gomiero et al 2011:107). Bat activity is between
61-84% higher on organic farms (Hole et al 2005:117) and birds are in greater
abundance. A study in Sweden (Rundlof et al 2008) found a greater abundance of
butterflies on organic farms, although an earlier study (Weibull et al 2003) found no
difference in biodiversity between organic and conventional farms. Here the authors
suggest that rather than the farming style, the heterogeneity of the landscape has a
bigger influence on biodiversity (Gomiero et al 2011:107).
Table 3.2: The effects of organic farming on biodiversity, compared to
conventional farming (From Hole et al 2005:122)
Diverse landscapes have a greater number of habitats and are thus able to support a
greater range of biodiversity; conventional farming often lowers heterogeneity
through the removal of hedgerows and promotion of monoculture. By eschewing
61
agro-chemicals and promoting a greater number of crop varieties, with longer crop
rotations, as well as encouraging hedgerows and set-a-side, organic farming creates a
greater on farm heterogeneity and thus encourages biodiversity.
For this to work to its full effect, landscape level heterogeneity must also be
increased, since the positive environmental effects of one organic farm can easily be
outweighed by the impacts of conventional farming in the surrounding landscape.
Benton et al (2003) have argued that rather than concentrating on farming style, focus
should be shifted to promoting diversity across the landscape in order to increase
biodiversity; since organic farms remain a minority, their full benefits may not be
fully realised due to the negative effects from conventional farming.
Aside biodiversity, organic farming can also have a positive effect on soils. Intensive
farming can lead to soil erosion and losses of soil organic matter (SOM) (Gomiero et
al 2011:100). On conventional farms, such issues are usually fixed through the
addition of extra chemicals to the soil, but this is not available in organic farming.
What has been observed however is that under organic conditions, SOM improves
naturally over time.
In America, a 40 year long study (Reganold et al 1987) found that compared to
conventional soils, organics had on average a 3cm thicker surface horizon and 16cm
deeper topsoil, as well as experiencing soil loss of less than 75% of the maximum
region tolerance, whereas conventional losses were three times that. A study by
Pimentel et al (2005) found that soil carbon increases on organic farms were almost
30% compared to only 8.6% on conventional farms. A 150 year study in Britain found
a 120% increase in SOM and soil N levels compared to only a 20% increase on
conventional farms using fertiliser (Gomiero et al 2011:101).
Organic soils also have increased pools of stored nutrients, with stability of
percolation and aggregate between 10-60% higher than conventional soils (Gomiero
et al 2011:101). Planting cover crops increases soil stability and prevents soil erosion,
providing that the vegetation cover is kept year round (Gomiero et al 2011:1010). Soil
health can be indicated by high amounts of earthworms, arthropods and microbial
biomass; with organic soils being found to have up to 320% greater abundance of
62
earthworms and microbial biomass when compared to conventional soils (Hole et al
2005:116; Gomiero et al 2011:105).
Compared with conventional soils, organic soils appear to have a greater water
retention capacity (Swiss trials found water holding capacity to be 20-40% greater)
which provides organic crops with the ability to fare well during droughts (Gomiero
et al 2011); organic yields during drought periods have been demonstrated to be
between 70-90% higher than conventional yields during drought periods.
A 1% increase in SOM can add 10-11 litres of plant available water per hectare to
soils (Sullivan 2002), and this is potentially very important at a time where pumped
irrigation could be limited and where climate is becoming increasingly variable,
although extensive experimentation to “gain better understanding of the complex
interactions of farming practices, environmental characteristics and agroecosystem
resilience” (Gomiero et al 2011:103) has been called for.
It has already been discussed how organic farming has a lesser energy burden, and
thus lower overall GHG emissions than conventional farming. It can also provide
opportunities to reduce greenhouse gas emissions associated with agriculture and can
mitigate against atmospheric CO2 through carbon sequestration (Adler et al 2007;
Johnson et al 2007; Smith et al 2008; Eglin et al 2010; Scialabba & Müller-Ludenlauf
2010).
Figure 3.4 Sources of N2O and CH4 emissions in the USA (From Johnson et al 2007:109)
63
In agriculture, methane emissions (Figure 3.4) are a result of livestock production,
waste decomposition (including crop residues) and rice paddies (Johnson et al 2007;
Smith et al 2008). Methane emissions from agriculture could be reduced by up to
56% through careful management practices (Smith et al 2008:802) and it has been
suggested that CH4 uptake by soils could offset up to 21% of cattle emitted CH4
(Johnson et al 2007:115); both of these can be carried out in either farming type, thus
organic farming does not offer any opportunities to reduce CH4 emissions compared
with conventional farming (Stolze et al 2000:59).
By avoiding the use of chemical fertiliser, organic farming straight away avoids direct
N2O emissions, which account for 10% of global agricultural emissions (Scialabba &
Müller-Ludenlauf 2010:161). Organic manures (used in place of chemical fertilisers)
can result in greater N2O emissions (Figure 3.4) compared with chemical N fertilisers,
although this is highly dependent on soil types and not always the case (Scialabba &
Müller-Ludenlauf 2010:161). The use of cover crops in organic farming increase N2
fixation and thus absorb greater amounts of N, reducing N2O emissions from topsoil
(Scialabba & Müller-Ludenlauf 2010:161; Gomiero et al 2011:102), as well as
keeping greater amounts of N within the plant system.
A number of trials have found that organic soils perform better in preventing N
leaching than conventional soils (Gomiero et al 2011:102). Compacted soils are a
major source of N2O emissions and since organic soils have enhanced aeration, this
risk is mitigated (Scialabba & Müller-Ludenlauf 2010:161). Overall organic systems
have around 66% less N2O emissions than conventional farming (Stalenga & Kavalec
2008).
CO2 emissions from organic agriculture arise from the combustion of fossil fuels
during the operation of farm machinery. Here emissions can only be reduced through
less use of machinery (or through the use of biofuels (see Section 3.2)); practices such
as conservation tillage can lead to less machinery use (Johnson et al 2007:111; Smith
et al 2008:791; Gomiero et al 2011:104) potentially reducing global CO2 emissions
by 15% (Lal 2004) but again it is not an approach unique to organic farming. And has
64
been seen, some practices can lead to increased fossil fuel consumption (Stolze et al
2000:68) compared to conventional farming.
Many organic practices such as mulching, continuous cropping, cover cropping,
legume rotations and manure applications can improve the carbon content of organic
soils (Johnson et al 2007:112; Eglin et al 2010:712) and thus organic farming can be a
method to improve the balance of agricultural greenhouse gas emissions (Leifield &
Fuhrer 2010:586). Pretty et al (2002) found that organic soils have carbon
accumulation increase from 0.3 to 3.5t per hectare per year, although some have
warned that such a sink can only be temporary, lasting around 100 years (Foeried &
Høgh-Jensen 2004).
Soils can also be used to manually sequester carbon, through the addition of black C
such as biochar (Woods et al 2010:3003). Calculations by Lee et al (2010) indicate
that in 1 hectare of arable land, 303.8 tons of carbon can be stored. The United
Kingdom possesses some 6.2m ha of arable land, providing the storage potential for
1.8GtCyr-1 of biochar. This could potentially offset over 300% of UK emissions;
although it is highly unlikely that the full potential would ever be realised, manual
sequestration of carbon into organic soils does offer a significant GHG mitigation
opportunity.
As well as the carbon sequestration, the addition of biochar to arable soils has a
number of other advantages; field trials have shown that biochar increases soil
hydraulic conductivity, permeability and holding capacity (Stavi & Lal 2010:165). It
also reduces soil acidity (Pratt & Moran 2010:1150), reduces nutrient leaching,
decreases N20 emissions (by 50%), suppresses CH4 emissions and increases fertiliser
efficiency and crop yields (Gaunt & Lehmann 2010:4152, 4155; Stavi & Lal
2010:165; Pratt & Moran 2010:1150; Atkinson et al 2010).
65
3.4 Local Food Production, Food Miles and Sustainability Implications
The transportation of food currently accounts for 18% of total energy use in the UK
food sector (White 2007:1243), equating to 2% of the UK total energy consumption.
The majority of transportation is carried out by HGV; with food transportation
accounting for 25% of all HGV vehicle kilometres in the UK (24.6bn km), causing
the emission of 10m tonnes of CO2 (AEA 2005:ii). The annual amount of food
moved by HGV has increased by 23% since 1978 (AEA 2005:i).
As previously mentioned, the depletion of oil supplies could lead to the greater
adoption of alternative forms of transport such as canals, rail and sea to move produce
around the UK.
The concept of food miles has become increasingly popular in the UK (Saunders &
Barber 2008; Coley et al 2009; Chi et al 2009) as both producers and consumers have
sought to examine the environmental credibility of products, especially their carbon
emissions. Food miles have become “powerful polemical tools in policy discourses
built around sustainable agriculture and alternative food systems” (Coley et al
2009:150) but are they really a proper indicator of sustainability?
A number of studies (AEA 2005; Saunders & Barber 2008; Coley et al 2009) have
established that the idea of freighted food having a great environmental impact than
local food can often be incorrect. In their study for Defra, AEA (2005) demonstrated
that tomatoes can be grown in Spain and freighted to the UK with less emissions than
if they were grown directly in the UK. This is due to UK tomatoes needing to be
grown in heated greenhouses outside of summer months and thus requiring greater
energy inputs (AEA 2005:v) which gave UK tomatoes greater emissions. Saunders &
Barber (2008) found that the majority of New Zealand food imports to the United
Kingdom had lower carbon emissions than UK grown equivalents.
They found that for most New Zealand products, the chemical inputs to agriculture
were at least half that of UK products (meaning less overall emissions), as well as the
fact that it was less emitting to freight New Zealand apples to the UK at any time of
66
the year compared to keeping UK apples in refrigerated storage until they were
needed (Saunders & Barber 2008:81).
It is also the case that vegetables grown by farmers in Africa often have lower
emissions associated with them than UK vegetables. This is because they are farmed
manually with little mechanisation or chemical inputs (McKie 2008) although once
airplane emissions are factored in, this figure can be up to 12 times greater than UK
vegetables (Chi et al 2009:38). What this fails to take into account however is the fact
that up to 80% of fruit and vegetables flown out of Africa are mostly transported via
backloading i.e. they are carried in the cargo hold of UK bound passenger planes
which would have flown anyway (Chi et al 2009:38) and thus the transport stage of
these products is insignificant in terms of emissions.
Of course, if the local produce is organic, then many of the above arguments are
negated, as the emissions from the organic farming will most likely be less than those
of freighted produce.
Food miles also fail to take into account other aspects of the global food market.
Through the export market, the importing of produce in the UK, provides economic
development opportunities for farmers in developing countries (MacGregor & Vorley
2006). In 2005 exports to the UK from sub-Saharan Africa had a declared value of
£200 million (MacGregor & Vorley 2006:3) and provided employment for around 1.5
million people (both directly in agriculture and indirectly in related business such as
transport, packaging and so forth) (MacGregor & Vorley 2006:7). This allows
individual farmers to move away from subsistence farming by providing access to the
global export market and through this individuals in developing countries can
experience improved incomes and higher standards of living.
It is therefore reasonable to suggest that the food miles are not an accurate indicator of
the sustainability (or green credentials) of a product. Focussing should instead be on
producing a carbon footprint for the product via a full life cycle analysis, as this will
be able to show its full environmental impact and enable consumers to make ‘green’
choices when purchasing produce.
67
The other side of the argument to the above mentioned international development
aspects of a global food market, the local food market is shown to have numerous
benefits for communities in the UK (Milestad et al 2010). The definition of local food
is not defined by any official characteristic, instead the consumer sets their own
definition of what they view as local (Milestad et al 2010:229), although by its nature
local food is normally fresher, more ‘authentic’ and in many cases unprocessed
(Milestad et al 2010:228). Local food allows the consumer to have much more
information about the ecological costs of the produce they purchase, due to a
shortened supply chain whereby the producer often sells direct to the consumer
(Sundkvist et al 2001:218) and by purchasing either direct from the producer, or via
local shops and farmers markets more of the money spent remains in the local
economy (Martinez et al 2010:42).
A study by the New Economics Foundation into the economy of local produce, found
that for every £10 spent on a local organic box scheme £25 is generated for the local
economy, compared to only £14 if the equivalent was spent in a supermarket (Pretty
2001:6). They also suggested that if every business and person in the area switched
1% of their current spending to local goods and services then an extra £52 million
could be generated in the local economy. Money put into local produce stays in the
local economy as the farmer uses some of the money to purchase a drink at the local
pub, the landlord spends some of that money on servicing his car at the local garage
and so on; if this money is spent at a supermarket, the money leaves the area almost
instantly.
In turn a greater demand for local produce and an increase in money available in the
local economy can bring about the creation of jobs either directly (working in the
farm) or indirectly in supporting roles (such as butchers, bakers, shopkeepers, delivery
drivers etc.).
As with the Breadshares Community Bakery, investment in local business allows
producers to purchase supplies up front and allows them to embark on projects that
traditional sources of funding (i.e. the bank) might have deemed too risky.
68
The local food system is also a source of community cohesion. Local shops and
delivery schemes allow individuals to meet and talk on a regular basis; it can ensure
that the elderly and infirm are regularly checked on and helped out (Lawrence
2004:123) and it can provide localised advertising for jobs and services carried out by
individuals within the area (Pretty 2001:5).
There are also ecological conservation aspects of local food; individuals purchasing
local organic produce may be doing so on the basis that the farming practices are
ecologically sound/environmentally friendly and thus by purchasing this produce,
they are investing in the protection of local ecology.
Studies of local bread networks in Austria (Milestad et al 2010) and Sweden
(Sundkvist et al 2001) found that locals participated in the networks, purchasing
products from them even though cheaper ‘non-local’ alternatives were available
(Sundkvist et al 2001:225) indicating that local produce had a greater value attached
to it.
When interviewing participants (producers and consumers) in the networks, it was
found that overall the participants in both networks had the same reasons for doing so
(Milestad et al 2010):
• Artisan production methods
• Organic farming
• High quality products
• Social interactions
• Benefiting the local economy
The authors of the Austrian study summed up the network as “social closeness
connected to the mode of production via shared values” (Milestad et al 2010:237) and
this is a phrase that could be used to describe those involved in the Breadshares
Community Bakery.
As we have seen, the concept of food miles itself is not a valid indicator of a product’s
sustainability. Food that is imported can be more environmentally friendly than
69
produce grown locally and the export market has provided economic growth for
farmers in developing countries. However if local food is produced organically it can
have a very low environmental impact and purchasing local food can have numerous
benefits for a community.
70
Chapter 4: Conclusion
The examination of organic farming, localised production and sustainability has
brought about a number of conclusions.
The adoption of organic farming offers considerable benefits; adoption of organic
farming can save up to 51% of energy use associated with agriculture and would
make food supply less dependent on oil thus increasing food security at a time when
oil production is at its peak.
The environmental benefits that organic farming can provide are numerous, the most
important aspects being that chemical pesticides and fertilisers are avoided,
preventing water and air pollution and not harming biodiversity. The preservation and
re-introduction of hedgerows and set-a-side provide habitats and increase the
heterogeneity of the landscape, encouraging biodiversity.
Organic farming can also go someway to reducing GHG emissions from agriculture
and mitigating CO2 emissions already present in the atmosphere, through the
improvement of soil carbon and by manually sequestrating carbon into the soil
through materials such as biochar. The latter, however, is not unique to organic
farming and is a mitigation strategy that could also be carried out in conventional
farming.
A number of the environmental benefits offered by organic farming could also be
achieved through carefully managed conventional farming. Whether this be through
the careful application of agro-chemicals or the re-establishment of habitat areas such
as hedgerows to encourage biodiversity, conventional farming is not as damaging to
the environment as may be portrayed.
Although yields may be lower under some circumstances in organic farming, this
does not necessarily have to impact upon food security since lower yields can still
adequately feed the global population if there is a switch to a less meat based diet.
71
The concept of food miles has been demonstrated to be a poor indicator of a product’s
environmental credentials. Instead the full life cycle of a product must be evaluated to
fully understand the impact that it has. Whilst importing produce from abroad can
offer carbon savings in certain conditions, and can provide economic relief to
producers in developing countries, local food also has a number of benefits to the
local area. It can lead to job creation and an improvement of the local economy; for
every £10 spent on local produce, there is a net benefit of £25 to the local economy.
The carbon footprint calculated for a loaf of bread created by the Breadshares Bakery
ranges from 0.39kgCO2e to 0.47kgCO2e depending on the mix of electricity used
during the production stage. These figures were between half and two thirds less than
the carbon footprints of breads calculated in other studies, with the major reductions
in emissions due to the organic farming method, the absence of transport between
production nodes and the use of on-site generated electricity.
If a delivery scheme for Breadshares bread was to be implemented, it would add on
up to an extra 66% to the carbon footprint of a loaf, although this would still perform
better than other loaves of bread. As well as being more environmentally friendly in
the long run, as delivering to seventy addresses over 40 miles is better than those 70
people individually driving to purchase bread.
This demonstrates the sustainability of projects such as the Breadshares Bakery which
shorted the chain of production and reveals how the carbon footprint of foods could
be reduced in order to try and mitigate against climate change.
72
Appendix A: Detailed Calculations for Life Cycle Inventory Analysis
Input Amount Source Raw Materials
Flour –Wheat Cultivation
kg CO2e per kg wheat 0.4 AgiLCA model
Flour – Wheat Milling
Mill yield per hour (kg) 100 Farmer interview
Power consumption of mill
(kWh)
6.25 Farmer interview
Power consumption per kg
flour (kWh)
0.0625 Calculation: power
consumption of mill / mill
yield
kg CO2e per kWh 0.362 The Scottish Government
kg CO2e per kg milled wheat Scenario A: 0
Scenario B: 0.01131
Scenario C: 0.02262
Calculation: power
consumption per kg x
emissions per kWh
kg CO2e per kg flour Scenario A: 0.4
Scenario B: 0.41131
Scenario C: 0.42262
Calculation: kg CO2e per kg
wheat + kg CO2e per kg
milled wheat
Flour
kg wheat per loaf 0.6 Baker interview
kg CO2e per loaf Scenario A: 0.24
Scenario B: 0.24678
Scenario C: 0.25357
Calculation: emissions per kg
flour x kg wheat per loaf
Yeast
kg CO2e per kg -0.0556 Emissions database
kg yeast per loaf 0.08 Baker interview
kg CO2e per loaf -0.004448 Calculation: emissions per kg
yeast x kg yeast per loaf
Salt
kg CO2e per kg 0.167 Emissions database
kg salt per loaf 0.05 Baker interview
kg CO2e per loaf 0.00835 Calculation: emissions per kg
salt x kg salt per loaf
73
Water
kg CO2e per kg 1.5x10-4 Scottish Water
kg water per loaf 0.4 Baker interview
kg CO2e per loaf 6.0×10-5 Calculation: emissions per kg
water x kg water per loaf
kg CO2e per loaf Scenario A: 0.243962 Scenario B: 0.250748 Scenario C: 0.257534
Calculation: emissions from
flour per loaf + emissions
from yeast per loaf +
emissions from salt per loaf +
emissions for water per loaf
Processing
Generic Oven
Power consumption of oven
(kWh)
24.72 Baker Interview
Capacity of oven (loaves) 36 Baker Interview
Oven operation time (hours) 1 hour (15 minutes heating
up + 45 minutes per baking
period)
Baker Interview
Baking Periods 2 (72 loaves = 1 hour 45
mins)
Baker Interview
Power consumption per loaf
(kWh)
0.601 Calculation: (power
consumption of oven x
operation time)/capacity
kg CO2e per kWh 0.362 The Scottish Government
kg CO2e per loaf Scenario A: 0 Scenario B: 0.1088 Scenario C: 0.2176
Calculation: power
consumption per loaf x
emissions per kWh
Breadshares Oven
Power consumption of oven
(kWh)
5.162 Baker Interview
Capacity of oven (loaves) 25 Baker Interview
Oven operation time (hours) 8 Baker Interview Baking Periods Up to 9 (For this 15 minutes
initial heating + 2 baking
periods of 45 minutes used)
Baker Interview
Power consumption per loaf 0.180 Calculation: (power
74
(kWh) consumption of oven x
operation time)/capacity
kg CO2e per kWh 0.362 The Scottish Government
kg CO2e per loaf Scenario A: 0 Scenario B: 0.03258 Scenario C: 0.06516
Calculation: power
consumption per loaf x
emissions per kWh
Consumption
Power consumption per slice
(40g) of bread (kWh)
0.047kWh Espinoza-Orias et al (2011)
kg CO2e per kWh 0.362 The Scottish Government
Slices of bread toasted per
loaf
8.775 Calculation: (39% of loaf) /
40g
kg CO2e per loaf 0.1493 Calculation: power
consumption per slice x
emissions per kWh x no.
slices
Total per loaf (kg CO2e) Scenario A: 0.393262 Scenario B: 0.508848 Scenario C: 0.624434
Calculation: emissions raw
materials + emissions
processing + emissions
consumption
Proposed Delivery
Round trip distance (miles) 44 Calculation
kg CO2e per litre of diesel 2.672 DEFRA (2010)
Van fuel economy (mpg) 37 Van average
Van fuel economy (mpL) 8.13 Calculation: mpg / 4.55
Number of loaves per van 70 Baker Interview
kg CO2e per loaf 0.206 Calculation: ((distance / fuel
economy) x
emissions)/number of loaves
Proposed Packaging
kg CO2e per bag 0.012 Berners-Lee (2010)
Proposals total per loaf (kg CO2e)
0.218 Calculation: transport
emissions per loaf +
packaging emissions per loaf
75
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