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Total greenhouse gases

The total greenhouse gases from food is taken to be 2.2 tonnes CO2 equivalent per person per year.

The components of this are shown in the table below. All figures below are per year.

Component	UK million tonnes	Tonnes per person	Avoidable tonnes per person
Fertilizer use	42	0.7	0.7
Meat and dairy consumption	24	0.4	0.4
Food transportation	17	0.3	0.25
Packaging	14	0.23	0.2
Processing of food	11	0.18	0.15
Decomposition of food	13	0.22	0.2
Unavoidable	11	0.18
Total	132	2.21	1.9

Other estimates are:

Per person per year	Source	Notes
0.6 tonnes CO2	[1]	for food and drink
1.4 tonnes CO2	[2]	'Food and catering'
1.9 tonnes CO2 equ.	[3]	(The Cabinet Office report) from a UK total of 116 Mt CO2 equivalent for food - 110 Mt plus an allowance of 6 Mt for the balance of imports over exports (21 less 15 Mt)
2.0 tonnes CO2 equ.	[4]
2.1 tonnes CO2 equ.	[5]	the main difference from source [2] is in the inclusion of methane and nitrous oxide as an equivalent amount of CO2.

Mt = million tonnes

Fertilizer use

• Use of fertilizers generates nitrous oxide on breakdown in the soil. This is 27 Mt CO2 equivalent [5].
• Manufacture and transport of fertilizers generates 9 Mt CO2 [5].
• This total of 36 Mt CO2 equivalent for UK fertilizer use is equal to 0.6 tonnes CO2 equ. per person. It should be scaled up to allow for UK food production being less than UK consumption. Overall UK production is only 60% of UK consumption [3], but for meat, the figure is 80-90%. Since meat production is much more energy intensive than fruit and vegetables, the scaling up will assume a figure of 85% giving an estimate 0.7 tonnes CO2 equ. per person.

So switching to organic food can reduce an individual's carbon footprint by 0.7 tonnes CO2 equ.

Meat and dairy foods

• Production of meat and dairy products generates methane from animals and slurry, which amounts to 19 Mt CO2 equivalent [5].
• CO2 from meat and dairy farm operations amounts to 3 Mt CO2 [5].
• This total of 22 Mt CO2 equiv from meat and dairy production should be scaled up to allow for UK meat and dairy production being equal to around 90% of UK consumption [3], giving an estimate of 24 Mt CO2 equivalent (0.4 tonnes per person).

So switching to a vegan diet can reduce an individual's carbon footprint by 0.4 tonnes equ.

Food transportation

• UK road transport of food generates 7 Mt CO2 [3][5]
• Road transport outside the UK plus sea transport generate 7 Mt CO2 [3][5] (2/3 and 1/3 respectively)
• Air freight generates 3 Mt CO2 [3]
• The total of 17 Mt CO2 is equivalent to 0.3 tonnes per person.

So switching to buying local food could save most of this total e.g. 0.25 tonnes per person.

Packaging

• The manufacture of food packaging generates 10 Mt CO2 [5]
• The methane and CO2 from decomposition of biodegradeable packaging in landfill sites is 4Mt CO2 equ. [5]
• The total of 14 Mt CO2 is equivalent to 0.23 tonnes per person.

Buying minimally packaged foods could save most of this total i.e. 0.2 tonnes per person.

[Composting organic packaging could save a proportion of it]

Processed food

• The processing of food generates 11Mt CO2 [5] (0.18 tonnes per person).

Avoiding processed food could save most of this i.e. 0.15 tonnes per person

Food waste

In the UK, about one third of the food bought is thrown away, and at least half of this is food that could have been eaten [6]. Inedible food includes potato peelings, bones, banana skins and teabags. Edible food can be discarded because too much is prepared, or because it has gone past its use-by date and so on.

Another way of looking at this is that relative to food eaten, on average another 25% is wasted, and a similar amount is inedible food.

If this 25% waste is reduced by half to 12.5%, then the edible food bought falls from 125% of what is eaten to 112.5%, and all emissions connected with food fall by one tenth - and the total amount discarded (edible plus inedible) falls by one quarter.

If someone throws away more food than average by half as much again, then the edible food bought rises from 125% of what is eaten to 137.5%, and all emissions connected with food rise by one tenth - and the total amount discarded (edible plus inedible) increases by one quarter.

Landfill decomposition of food

• The rotting of unused food in landfill sites releases gases (methane and CO2) that total 13 Mt CO2 equ [5] (0.22 tonnes per person)

Composting or re-using food residues could save most of this i.e. 0.2 tonnes per person. This amount would be more or less depending on how much edible food is wasted.

Greenhouse gases that are hard to avoid

These comprise [5]

• methane from tilling and soil management (4 Mt CO2 equ.)
• CO2 from arable farm operations (3 Mt CO2)
• operation of retail stores (4 Mt CO2)

These total 11 Mt CO2 equ (0.2 tonnes per person)

Miscellaneous points

UK food production is only 60% of UK consumption [3]

Food exports from the UK are worth around £6.5bn - with cereals and fish making the largest contribution [3] .

Food imports are worth almost £20bn, vegetables and fruit being the largest category [3] .

The origin of UK food is as follows (2006 data, based on unprocessed farm-gate prices) [3] :

Origin	Proportion
UK	49%
Europe (EFTA)	29%
Africa	6%
Asia	5%
N. America	5%
S. America	4%
Other	3%

Units & Abbreviations

Mt: million tonnes (referring to the UK total)
CO2 equ. : CO2 equivalent
Figures given are per year

References

[1]	www.carbonfootprint.com/results.php (viewed 13.8.06)

[2]	Carbon Trust (2006) The carbon emissions generated in all that we consume www.carbontrust.co.uk or www.carbonindependent.org/files/ctc603.pdf

[3]	The Cabinet Office Strategy Unit (2008) Food: an analysis of the issues www.cabinetoffice.gov.uk or www.carbonindependent.org/files/cabinet_office_food_analysis.pdf

[4]	Ethical Consumer Magazine Your Contribution to Climate Change (July/August 2005) (www.ethicalconsumer.org) and www.quakergreenaction.org (accessed 13.8.06) - see also [7]

[5]	Chris Goodall (2007) How to live a low-carbon life (Earthscan)

[6]	WRAP (2007) Understanding Food Waste www.wrap.org.uk or www.carbonindependent.org/files/foodwasteresearchsummaryfinaladp29_3__07_25a4c08b.b8683843.pdf

[7]	Your Contribution to Climate Change (June 2007) www.livingwitness.org.uk (accessed 20.1.08), an update of source [4]

First published: 2008
Last updated: 13 Sep 2023