Global warming potential associated with dairy products in the Republic of Ireland

Abstract

In 2015, the milk quota system that is in place in Europe is to be abolished, instigating an increase in milk production. This increase will aid in addressing the world's ever growing demand for food, but will incur increased stresses on the environmental impact and sustainability of the dairy industry. In this paper, an environmental life cycle assessment, which is performed in order to estimate the global warming potential (GWP) associated with 11 dairy products in the Republic of Ireland, is presented. The primary aim of the study is to examine the GWP associated with the processing of raw milk into the various products. However, the GWP contribution from dairy farms producing the raw milk is also included. Therefore, the system boundary utilised in this study is cradle-to-processing factory gate (dairy, farm, raw milk transportation and dairy processing). Furthermore, when performing the analysis, the 11 dairy products are clustered into 6 product groups: fluid milk (whole milk, skimmed and semi-skimmed milk); butter; cheese; cream; milk powders (buttermilk powders, whole milk powders, skimmed milk powders, and chocolate crumb); and whey powders (whey powders and proteins). The total GWP was calculated for each product group and mass allocation was used to derive the GWP of each product within that group. Data from 12 companies (18 dairy processing plants), which account for approximately 92% of the cow's milk processed in the Republic of Ireland, was used in this study to accurately assess the Irish dairy processing industry. From the analysis, it was found that raw milk production accounted for between 80.8% and 97.3% of the total GWP, depending on the amount of raw milk per kg of product. Additionally, raw milk transportation accounted for approximately 0.4% of the GWP, with the remainder contributed by the processing phase. The main contributor to GWP in the processing phase was direct energy use within the plant (electricity, natural gas and other fuel), which accounts for between 91 and 98% of the GWP, depending on the product. Furthermore, even though raw milk production is the most significant contributor to the total GWP of each dairy product, it was observed that energy use and water consumption in the processing phase were of the same magnitude as that of the production phase.