PhD thesis on GHG from milk and dairy

FCRN mailing list member Anna Flysjö has successfully defended her thesis.  The thesis takes the form of a summary overview section and 6 papers (5 of them published journal papers). Details as follows:

The 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 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 CH₄ and N₂O emissions, assessment of CO₂ emissions from land use change (LUC), co-product handling, and definition of the functional unit. Estimates of the biogenic emissions CH₄ and N₂O 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.

Reference

Flysjö A (2012). Greenhouse gas emissions in milk and dairy product chains improving the carbon footprint of dairy products, PhD thesis, Aarhus University, 2012

You can download the thesis here.

You can find other dissertations and theses on the FCRN website here.