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Environmental impact of food: Lifecycle greenhouse gas assessments

Direct greenhouse gas (GHG) emissions – such as from homes, factories and transport – are relatively easy to measure. But a large quantity of GHGs are also ‘embedded’ in the products and services we consume.

Once these emissions become measurable, their reduction also becomes more straightforward. To this end, Defra worked with the Carbon Trust, to co-sponsor the development of a Publicly Available Specification (PAS) by the British Standards Institute. This has delivered a robust and industry-wide standard to measure embedded GHGs in all products and services. 

A carbon standard for goods and services PAS 2050: 2008

Specification for the assessment of the lifecycle greenhouse gas emission of goods and services (29 October 2008)

  • PAS 2050 method is technically rigorous and provides a consistent and clear framework to calculate life-cycle greenhouse gas emissions.  It can be applied across a wide range of industry sectors, and products including food. 
  • This carbon standard can be used to identify key sources of emissions, or “hot spots”, in the supply chain and therefore help prioritise emission reduction initiatives. It can also help businesses to innovate around the development of lower carbon goods and even phase out carbon intensive goods and services in favour of lower carbon alternative.  Finally PAS 2050 will be able to provide customers with transparent and reliable information about the carbon footprints of goods and services which can then be factored into purchasing decisions

In the longer term the project aims to influence future standards development at European Union and International Standards level.

Food products are a major focus of this work, given the complexities of their production; for example, agriculture involves significant emissions of greenhouse gases besides carbon dioxide. In addition, there is a high level of public and retailer interest surrounding them.

Research Projects

Defra recently funded a suite of research projects to test and inform the development of PAS 2050, a Publically Available Specification to assess life cycle green houses gas emissions in goods and services. These projects intended to establish the suitability of the PAS2050 methodology for use in the food sector by generating robust data on GHG impacts for:

These projects provided feedback and commentary on the suitability of the PAS2050 methodology at various draft stages prior to launch of the specification in October 2008.

The projects have shown that PAS2050 can be applied to a variety of food commodities and products through the supply chain.  In general, GHG emissions were of the same order for production systems with different levels of intensification.  Extensive systems have lower emissions associated with inputs and processes per area of land, but also have lower yields from that land.  Intensive systems have higher yields but also require more inputs and therefore have higher GHG emissions.

Emissions of GHGs from manufactured foods tended to be dominated by emissions from the production stage, i.e. agriculture.  At the retail and distribution stage, refrigeration is responsible for a major part of the electrical energy consumption of retail food stores. Refrigeration systems are also responsible for direct emissions through refrigerant gas leakage. In the home, packaging and pack size are key drivers of household waste.  Wasted energy (oven use) is also an important factor in the home.

Cottage Pie Case Study

In addition a case study on a cottage pie (PDF 250KB) was carried out using information obtained from across the three projects.

A further study, ‘Comparative life-cycle assessment of food commodities procured for UK consumption through a diversity of supply chains’ (Defra research project FO0103), looked at the impacts of various imported foods, such as Brazilian beef, New Zealand lamb and Spanish strawberries. Further information on this project can be found on Defra’s science pages.

See also

Page last modified: 14 August 2009
Page published: 21 July 2009

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