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Greenhouse gas emissions in milk and dairy product chains: Improving the carbon footprint of dairy products

Abstract

The present PhD project has focused on some of the most critical methodological aspects influencing GHG emission estimates of milk and dairy products and how the methodology can be improved. In addition, the Carbon Footprint (CF) for different types of dairy products has been analysed. Based on these results, mitigation options have been identified along the entire dairy value chain. The key methodological challenges analysed in the present study are: estimation of CH{sub 4} and N{sub 2}O emissions, assessment of CO{sub 2} emissions from land use change (LUC), co-product handling, and definition of the functional unit. Estimates of the biogenic emissions CH{sub 4} and N{sub 2}O are associated with large uncertainties due to the complexity and natural variation in biological processes. Accounting for these variations resulted in a {+-}30-50% variation in the CF for milk in Sweden and New Zealand (excluding emissions from LUC). The inclusion of emissions from LUC can drastically affect the CF of dairy products, and different models can even provide contradictory results. Thus, it is suggested that emissions associated with LUC are reported separately and that underlying assumptions are clearly explained. Accounting for the by-product beef is decisive for the CF of milk, and when designing  More>>
Authors:
Publication Date:
Nov 01, 2012
Product Type:
Technical Report
Report Number:
NEI-DK-5765
Resource Relation:
Other Information: TH: Thesis (Ph.D.); 123 refs., 23 figs., 8 tabs.
Subject:
54 ENVIRONMENTAL SCIENCES; GREENHOUSE GASES; MILK PRODUCTS; FOOD CHAINS; CARBON FOOTPRINT; MITIGATION; METHANE; NITROUS OXIDE; CARBON DIOXIDE; LAND USE; MILK
OSTI ID:
22000600
Research Organizations:
Aarhus Univ.. Dept. of Agroecology Science and Technology, Tjele (Denmark)
Country of Origin:
Denmark
Language:
English
Other Identifying Numbers:
Other: ISBN 978-87-92869-25-8; TRN: DK1201260
Availability:
Available at http://pure.au.dk/portal/files/45485022/Anna_20Flusj_.pdf
Submitting Site:
DK
Size:
165 page(s)
Announcement Date:
Dec 19, 2012

Citation Formats

Flysjoe, A M. Greenhouse gas emissions in milk and dairy product chains: Improving the carbon footprint of dairy products. Denmark: N. p., 2012. Web.
Flysjoe, A M. Greenhouse gas emissions in milk and dairy product chains: Improving the carbon footprint of dairy products. Denmark.
Flysjoe, A M. 2012. "Greenhouse gas emissions in milk and dairy product chains: Improving the carbon footprint of dairy products." Denmark.
@misc{etde_22000600,
title = {Greenhouse gas emissions in milk and dairy product chains: Improving the carbon footprint of dairy products}
author = {Flysjoe, A M}
abstractNote = {The present PhD project has focused on some of the most critical methodological aspects influencing GHG emission estimates of milk and dairy products and how the methodology can be improved. In addition, the Carbon Footprint (CF) for different types of dairy products has been analysed. Based on these results, mitigation options have been identified along the entire dairy value chain. The key methodological challenges analysed in the present study are: estimation of CH{sub 4} and N{sub 2}O emissions, assessment of CO{sub 2} emissions from land use change (LUC), co-product handling, and definition of the functional unit. Estimates of the biogenic emissions CH{sub 4} and N{sub 2}O are associated with large uncertainties due to the complexity and natural variation in biological processes. Accounting for these variations resulted in a {+-}30-50% variation in the CF for milk in Sweden and New Zealand (excluding emissions from LUC). The inclusion of emissions from LUC can drastically affect the CF of dairy products, and different models can even provide contradictory results. Thus, it is suggested that emissions associated with LUC are reported separately and that underlying assumptions are clearly explained. Accounting for the by-product beef is decisive for the CF of milk, and when designing future strategies for the dairy sector, milk and meat production needs to be addressed in an integrated approach. It is shown that an increase in milk yield per cow does not necessarily result in a lower CF of milk, when taking into account the alternative production of the by-product beef. This demonstrates that it is important to investigate interactions between different product chains, i.e. to apply system thinking. The CF of dairy products from Arla Foods analysed in the present study range from: 1.2-5.5 kg CO{sub 2}e per kg fresh dairy products, 7.3-10.9 kg CO{sub 2}e per kg butter and butter blends, 4.5-9.9 kg CO{sub 2}e per kg cheese, and 1.0-17.4 kg CO{sub 2}e per kg milk powder and whey based products (excluding emissions from LUC). The large variation in the product group 'milk powder and whey based products' is a consequence of the allocation model for raw milk, where lactose is assumed to have no value and protein is valued at 1.4 times that of fat. Products with a high lactose content then result in a low CF, while products with a high protein content get a high CF. Hence, the choice of method for co-product handling is fundamental for the CF of dairy products. In addition, it is critical to define the functional unit - more specifically, to account for nutritional values or to differentiate between what is 'produced' and what is actually 'consumed', as there can be differences in product losses at consumer level between different products. Finally, small improvements at farm level can result in relatively large reductions in the CF of dairy products (compared to other life cycle stages), since emissions before farm gate are the largest source of the GHG. The large emissions related to raw milk from the farm also emphasizes the importance of reducing product losses throughout the entire value chain - from cow to consumer. (Author)}
place = {Denmark}
year = {2012}
month = {Nov}
}