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Putting horticultural emissions in a wider context. Gareth Edwards-Jones Katrin Plassmann Bangor University. Energy use in horticulture. Horticulture accounts for about 28% of the total energy used in UK agriculture.
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Putting horticultural emissions in a wider context Gareth Edwards-Jones Katrin Plassmann Bangor University
Energy use in horticulture • Horticulture accounts for about 28% of the total energy used in UK agriculture. • About 35% is used by the livestock sector and 37% by the arable sector (Warwick HRI 2007). • The total UK primary energy input into horticulture is split between sectors as: • 58% to protected edible crops (20% to tomatoes) • 33% to protected ornamentals • 9% to field crops
Direct energy expended by various sectors of agriculture in the UK by use in 2005 (from: Warwick HRI 2007).
Primary energy inputs into UK protected crops. (from: Warwick HRI 2007).
Wasted food is wasted energy • 25% of the total supply of fruit and vegetables goes to waste (Garnett 2006). • 12% of the fruit, vegetables and potatoes that enter the processing sector end up as waste. • In addition, about 170,000 tonnes of fruit and vegetables per year may be wasted in the retail sector (Garnett 2006). • The greatest volume of waste occurs in consumers’ homes, with 31% of consumers admitting to throwing away food because it has gone off ‘always, very often or quite often’ (Defra 2007).
Greenhouse gas (GHG) emissions from horticulture • In the only study that has attempted to estimate the GHG emissions of some of the UK’s horticultural sectors, Garnett (2006) estimated that the fruit and vegetable sectors contribute about 2.5-3% of total UK GHG emissions.
INPUTS OUTPUTS Machinery Pesticides Fertiliser Electricity Fuel Food Wastes Pollution Farm Transport Machinery Fuel Pollution Storage & processing Pollution Wastes Machinery Electricity Electricity Packaging Wastes Pollution Retail The food system
Global warming potential (GWP) in kg CO2 equivalents per kg of food/drink product in York(from: Barrett et al. 2002). Fresh potatoes 1.88 Fresh green vegetables 1.67 Butter 17.36 Cheese 13.86 Whole milk 3.52 Beef and veal 19.30 Mutton and lamb 13.09 Spirits (e.g. Whisky) 23.22 Wine 14.33 Coffee 13.62
Greenhouse gas emissions from the production, processing and distribution for food consumed in Sweden. Figures do not include home cooking (Wallén et al. 2004).
Emission of CO2 equivalents per year per capita in Sweden for different food categories (from: Wallén et al. 2004).
Estimates of carbon emissions for selected items and activities (from: ECCM 2000).
Some figures • The production of 1 kg of British outdoors lettuce emits 0.33 kg CO2 equivalents • The production of 1 kg of British glasshouse tomato emits 9.4 kg CO2 equivalents
Some cross-sector comparisons • Producing 1 t of tomatoes emits the same amount of GHGs in CO2 equivalents as does the production of 10 washing machines. • Growing 1 ha of peas in the UK emits the same level of CO2 equivalents as does running a 60 W light bulb for 930 days . • Growing 1 kg of indoor lettuce with heating requirements in the UK emits the same level of GHGs as does running a 40 W light bulb for 125 hours.
More comparisons • The annual methane emissions from a single dairy cow have an equivalent global warming potential to the production of 0.27 t of UK tomatoes. • The production of 12,000 roses in the Netherlands which are delivered to southern England emits the same amount of GHG emissions as does the electricity use of 4.7 small offices per year. • GHG emissions from 27.9 billion car kilometres driven in Wales in 2006 are 35 times greater than the GHG emissions from the production of the total amount of tomatoes consumed in Wales per year.
Carbon emissions in megatonnes of carbon per year from the different sectors of the UK food system (adapted from White 2007).
UK household CO2 emissions from consumption (food and eating out account for over 7% of emissions)(redrawn from WWF-UK 2006).
Conclusions • As a sector horticulture has relatively low emissions. • Protected cropping is a high emitter within the sector. • but these emissions are manageable • Society needs to move away from a food fixation and address the high emitting activities • Horticulture cannot win the war on its own – but it needs to do its bit.