Over 6 billion liters of Canadian milk wasted since 2012

Canada's dairy supply management system provides milk year-round but unnecessarily disposes of overproduction. A lack of transparent data on discarded milk means that the scale of this issue is unknown. This hinders actions to mitigate the potentially large environmental, economic and nutritional costs of avoidable, on-farm milk waste. Here we estimate the volume of surplus milk discarded on farms using a material flow analysis approach, and assess the related environmental and nutritional costs. By our estimates, over 6.8 billion liters of raw milk vanished from Canadian dairy farms since 2012 (totaling a value of $14.9 billion CAD). We calculate this is equivalent to 8.4 million tonnes of CO₂ emissions and enough milk for 4.2 million people (11 % of the Canadian population) annually. We suggest increasing transparency on the volume overproduction, reducing incentives for farmers to overproduce, and updating quotas to reflect shifting dietary needs as actions to align the Canadian dairy sector with broader food-system sustainability objectives.