Is drinking milk bad for the environment?

In this blog, I will answer a question that has been asked to me by many different people on many different occasions: “is drinking milk bad for the environment?”. I will go into the environmental impact of dairy production, as well as give my view on whether or not this means that we should stop drinking milk.

First of all, it is important to realize that environmental impact is not easy to define. It includes many aspects: greenhouse gas emission, land and water pollution (acidification, eutrophication), and more. For this blog, I will focus on greenhouse gas emission.

Looking at the whole dairy production chain,  the major greenhouse gas emission happens on the farm, which represent about two-thirds of total emission. On farm, methane and nitrous oxide emission are the major contributors. Cows produce methane during fermentation of feed in the rumen. During fermentation, methane is formed by specific microorganisms, which is subsequently emitted through burping, but also through manure. Nitrous oxide is mainly emitted from soil, where ammonia from manure & fertilizer can be converted into nitrous oxide that is released into the atmosphere. These two major sources of emission combined with all the other (relatively smaller) sources make that the dairy chain contributes about 2.8% to total global greenhouse gas emission.

But does this then mean that we should stop drinking milk? In my opinion such decision on diets should never be taken based on environmental impact alone. In the end, it is about the balance between environmental and nutritional impact. Milk has a major environmental impact, but also provides many beneficial nutrients to our diets. Studies optimizing diets based on balancing environmental and nutritional impact therefore generally show that milk consumption should not be decreased. So, due to counterbalancing of the environmental impact by its nutritional impact, my answer to the main question of this blog is no: we should not stop drinking milk due to its environmental impact. That doesn’t mean that reducing the environmental impact of dairy production is not relevant, but that’s a topic I will discuss in a separate blog.

If you are interested in plant-based dairy alternatives as a supposedly healthier and more environmental-friendly option, please read my other blog.

Kasper Hettinga, July 2018

 

Author: Kasper Hettinga

Associate professor Dairy Science & Technology