Abstract
Background, aim, and scope
Carbon footprint (CF) has become a hot topic as public awareness of climate change is placing demands on manufacturers to declare the climate impact of their products. Calculating the CF of food products is complex and associated with unavoidable uncertainty due to the inherent variability of natural processes. This study quantifies the uncertainty of a common food product and discusses the results in relation to different types of CF systems for food product labelling.
Materials and methods
A detailed LCI with global warming potential as the only impact category was performed on King Edward table potatoes grown in the Östergötland region of Sweden. Parameters were described using one probability distribution for spatial and temporal variation and one separate distribution describing measuring/data uncertainty, allowing the effect of parameter resolution on CF uncertainty to be studied. Monte Carlo simulation was used to quantify the overall uncertainty. The influence of individual parameters on the CF was analysed and differences in CF for food products from different production systems, with and without climate impact reduction rules, were simulated.
Results
The potato CF fell in the range 0.10–0.16 kg CO2e per kilogram of potatoes with 95% certainty for an arbitrary year and field. Emissions of N2O from soil dominated the CF uncertainty. Locking the temporal variation to a specific year lowered the uncertainty range by 19%. Parameter collection on a spatial scale of one field did not reduce the uncertainty. The most sensitive parameters were the yield, the soil humus content and the emissions factors for N2O emissions from soil. Potatoes grown according to climate rules lowered the CF by 9% with a probability of 53% for an arbitrary year and field.
Discussion
The importance of yield, which proved to be the most influential parameter, is a common characteristic of agricultural products in general, since the accumulated emissions from a cultivated area are divided across the yield from that area. Maximising the yield reduces the CF but could have negative impacts on other environmental aspects. The purpose of the CF labelling scheme, together with uncertainty analysis, needs to be considered when determining how the CF should be calculated, as an average or for a specific year, farm, field, region, etc.
Conclusions
The CF of a potato crop calculated for an arbitrary year and field varied between approximately -17% and +30% of the average value with 95% certainty, showing that uncertainty analysis in the design, calculation and evaluation of food product CF labelling schemes is important to ensure fair comparisons.
Recommendations and perspectives
Similar studies comparing different production systems for the same type of product and products from different categories, on large and small scale depending on the purpose of the CF system, are needed in order to determine how the CF of food products can be compared and the precision with which data have to be collected in order to allow fair and effective comparison of the CF of food products.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Notes
KRAV is an incorporated association with 28 members representing farmers, producers, trade, and consumers as well as environmental and animal welfare interests. KRAV develops organic standards and promotes the KRAV label for organic products. Seal Quality Systems Ltd is a wholly owned subsidiary of the Federation of Swedish Farmers (LRF). Seal Quality Systems Ltd owns and develops rules for the Swedish Seal of Quality (Svenskt Sigill) label (conventional farming).
References
Andrén O, Kätterer T, Karlsson T (2004) ICBM regional model for estimations of dynamics of agricultural soil carbon pools. Nutr Cycl Agroecosyst 70:231–239
Berry T, Crossley D, Jewell J (2008) Check-out carbon—the role of carbon labelling in delivering a low-carbon shopping basket. Forum for the Future, London
Björklund A (2002) Survey of approaches to improve reliability in LCA. Int J LCA 7(2):64–72
BSI (2008) PAS 2050 specification for the assessment of the life cycle greenhouse gas emissions of goods and services. BSI British Standards, London
CLfF (2009) The Climate Labelling of Food Product project. www.klimatmarkningen.se (visited 20.04.2009)
Carbon Trust C (2008) Product carbon footprinting: the new business opportunity. The Carbon Trust, London
EC (2007) Reference document on best available techniques for the manufacture of large volume inorganic chemicals—ammonia, acids and fertilisers. Integrated Pollution Prevention and Control, European Commission
Ecoinvent Centre (2007) Ecoinvent data v2.0. ecoinvent reports no.1–25. Swiss Centre for Life Cycle Inventories, Dübendorf
Finkbeiner M (2009) Carbon footprinting—opportunities and threats. Int J LCA 14:91–94
Frischknecht R, Jungbluth N, Althaus H-J, Doka G, Dones R, Heck T, Hellweg S, Hischier R, Nemecek T, Rebitzer T, Spielmann M (2004) The ecoinvent database: overview and methodological framework. Int J LCA 10(1):3–9
Frischknecht R, Althaus H-J, Bauer C, Doka G, Heck T, Jungbluth N, Kellenberger D, Nemecek T (2007) The environmental relevance of capital goods in life cycle assessments of products and services. Int J LCA 13:7–17 (special issue)
Heijungs R, Huijbregts MAJ (2004) A review of approaches to treat uncertainty in LCA. Proceedings of the IEMSS conference, Osnabruck
Huijbregts MAJ (1998) Application of uncertainty and variability in LCA. Part 1: a general framework for the analysis of uncertainty and variability in life cycle assessment. Int J LCA 3(5):273–280
IPCC (2006) IPCC guidelines for national greenhouse gas inventories, volume 4. Agriculture, forestry and other land use. Intergovernmental Panel of Climate Change
ISO (2006a) ISO 14040 International Standard. In: Environmental management—life cycle assessment—principles and framework. International Organisation for Standardization, Geneva, Switzerland
ISO (2006b) ISO 14040 International Standard. In: Environmental management—life cycle assessment—requirements and guidelines. International Organisation for Standardization, Geneva, Switzerland
Jenssen TK, Kongshaug G (2003) Energy consumption and greenhouse gas emissions in fertiliser production. International Fertiliser Society Meeting, London
Jungbluth N, Tietje O, Scholz R (2000) Food purchases: impacts from the consumers’ point of view investigated with a modular LCA. Int J LCA 5:134–142
Kasimir-Klemedtsson Å (2001) Metodik för skattning av jordbrukets emissioner av lustgas (Methodology for estimating the emissions of nitrous oxide from agriculture). Report 5170. Swedish Environmental Protection Agency, Stockholm, Sweden
L.E.K (2008) The L.E.K. Consulting Carbon Footprint Report 2007. L.E.K. Consulting llp, London, UK
LRF (2009) Miljöhusesyn 2009 (Environmental inspection 2009). The Federation of Swedish Farmers, Stockholm
Mattsson B, Wallén E, Blom A, Stadig M (2001) Livscykelanalys av matpotatis (Life cycle assessment of table potatoes). Internal report. The Swedish Institute for Food and Biotechnology (SIK), Gothenburg, Sweden
Nemecek T, Kägi T (2007) Life cycle inventories of agricultural production systems. Data v2.0 (2007), ecoinvent report no. 15, ecoinvent centre. Swiss Centre for Life Cycle Inventories, Dübendorf
Nordel (2005) Development and integration of regional electricity markets. Nordel, Oslo
NTM Calc (2009) Calculation tool from The Network for Transport and Environment. <http://www.ntm.a.se> (visited 19.02.09)
Olofdotter M, Juul J (2008) Climate change and the food industry—climate labelling for food products: potential and limitations. Øresund Food Network, Copenhagen
Röös E (2009) Carbon footprint of table potatoes—uncertainties and variations. Report 017. Department of Energy and Technology, SLU, Uppsala
Rubinstein R, Kroese D (2007) Simulation and the Monte Carlo method. Wiley-Interscience, ISBN 0470177942, 9780470177945
SCB (2008) Production of cereals, dried pulses, oilseed crops, potatoes and temporary grasses in 2007, final statistics. Statistics Sweden, Stockholm
Schmidt H-J (2009) Carbon footprinting, labelling and life cycle assessment. Int J LCA special issue “Life cycle performance of aluminium applications”
Schau EM, Fet AM (2008) LCA studies of food products as background for environmental product declarations. Int J LCA 13(3):255–264
Seal Quality Systems Ltd (2009a) IP sigill basregler—standard för kvalitetssäkrad primärproduktion av livsmedel (IP seal—standard for quality assured primary production of food products). Edition 2009:1. Seal Quality System Ltd., Stockholm, Sweden
Seal Quality Systems Ltd (2009b) IP sigill frukt & grönt—standard för kvalitetssäkrad produktion av bär, frukt, potatis, frilands- och växthusgrönsaker (IP seal—standard for quality assured production of berries, fruit, potatoes and vegetables). Edition 2009:1. Seal Quality System Ltd., Stockholm, Sweden
SEPA (2008a) Konsumtionens klimatpåverkan (The climate impact of consumption), report no 5903. Swedish Environmental Protection Agency, Stockholm, Sweden
SEPA (2008b) The general public and climate change 2008, report no 5905. Swedish Environmental Protection Agency, Stockholm
SEPA (2009) The National Inventory Report 2009 Sweden. Swedish Environmental Protection Agency, Stockholm
SETAC Europe LCA Steering Committee (2008) Standardisation efforts to measure greenhouse gases and 'carbon footprinting' for products (editorial). Int J LCA 13(2):87–88
SMAK (2009) Webpage of The Swedish Tablepotato Control Agency Ltd. Älvsjö, Sweden. www.smak.se (visited 01.04.2009)
Swedenergy (2009) Vägledning angående ursprungsmärkning av el (Guidance for origin labelling of electricity). Swedenergy, Stockholm, Sweden
Toivonen A (2007) Konsumenternas syn på klimatmärkta livsmedel—en konsumentundersökning (Consumer views on carbon labelled food products—a consumer review). MAT 21, SLU, Uppsala, Sweden
Weidema B, Wesnaes MS (1996) Data quality management for life cycle inventories—an example of using data quality indicators. J Clean Prod 4(3–4):167–174
Weidema B, Thrane M, Christensen P, Schmidt J, Løkke S (2008) Carbon footprint—a catalyst for life cycle assessment. J Ind Ecol 12(1):3–6
Author information
Authors and Affiliations
Corresponding author
Additional information
Responsible editor: Matthias Finkbeiner
Rights and permissions
About this article
Cite this article
Röös, E., Sundberg, C. & Hansson, PA. Uncertainties in the carbon footprint of food products: a case study on table potatoes. Int J Life Cycle Assess 15, 478–488 (2010). https://doi.org/10.1007/s11367-010-0171-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11367-010-0171-8