Carbon Footprint of Raw Milk and Other Dairy Products

Abstract

Dairy and livestock sector is a significant contributor of anthropogenic greenhouse gas emissions. Carbon footprint (CF) is commonly used to indicate the greenhouse gas (GHG) emissions (CO2 equivalent) at various life cycle stages of a product. Studies undertaken globally on CF of dairy products were reviewed, reported CF values for various products are summarized and important contributing factors are discussed. In various studies undertaken globally, CF of dairy products has been calculated by using different international standards and methodologies like ISO 14040, 14044 and 14067, publicly available specification (PAS 2050). Most of the studies have used functional units such as kilogram greenhouse gas emissions per kilogram of fat-and-protein-corrected-milk (FPCM) and energy correlated milk (ECM). Direct emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) from on-farm livestock production and indirect CO2 and N2O emissions related to inputs on the farm have generally been considered in various studies. Enteric methane (CH4) has been reported as the major source of dairy farm emissions, followed by manure management, fertilizer production and its application. Processed milk products were found to have higher CF value as compared to the unprocessed milk. Various mitigation strategies have been suggested for emission reduction from dairy farms for example balanced feed rations and concentrates according to animal body requirements during lactation period, reducing use of nitrogen based fertilizers and increasing efficiency in application during crop production, use of biogas in place of cow dung, anaerobic digestion (AD) and efficient manure management.