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Plant vs dairy – comparing their climate impacts

The greenhouse gas emissions of all plant based milk and cheese substitutes are likely to be significantly lower than cow’s milk and cheese. But judging the greenhouse gas emissions of anything is messy.

image: climate impact of plant vs dairy milk

There are always wide variations – partly due to the methodologies used, and partly because the difference between the best and worst producers is often huge.

Studies on the emissions of a litre of dairy milk, for example, have come up with answers that vary from 0.54 to 7.50 kgCO2eq.

However, if you look at lots of studies, certain basic patterns emerge and you can get a pretty good overall picture.

Milk: Greenhouse gas emissions of plant vs dairy milk

Our bar chart (right) shows average CO2 emissions per litre for various milks within Europe found by one large review study, led by Joseph Poore at the University of Oxford. (The almond figure is the global one as there was no figure for Europe.)

The global average figures from this study were quoted by the BBC, which include a higher figure for cow milk, but we’re giving the European figures as they are more relevant in the UK and also more similar to figures in other reviews.

Although figures differ between reviews, the pattern is basically consistent that cow’s milk is worse than the others, which isn’t that surprising, given the emissions of cows (see our feature on the climate impacts of meat and dairy).

Furthermore, as is mentioned in the feature, most life cycle figures do not include the greenhouse gas ‘opportunity cost’ of land use (the other things that you could do with the land, like reforesting it, that could potentially remove carbon from the air). If you do include that, animal products come out much worse. The ‘land used’ figures in the bar chart show why. (These figures are also from Joseph Poore, and again, for Europe except in the case of almond.) Basically, cow’s milk uses more land per litre than any of these plant milks.

Making reasonable guesses

There isn’t a huge amount out there on the other kinds of milk. One analysis suggested that coconut milk’s climate impact is similar to almond, and another suggested that pea’s is similar to oat. But you’d be lucky to find someone who has sat down and meticulously calculated the emissions of buckwheat milk. There is also very little out there on cheese substitutes.

However, it is possible to make reasonable guesses on the basis of the ingredients. The ingredients invariably make up the bulk of foods’ carbon footprint, with processing being a small part. This is true of all plant milks and of dairy cheese.

Cheese: Greenhouse gas emissions of plant vs dairy cheese

On the right are some figures for life cycle estimates of the greenhouse gas emissions of cheese, and the main ingredients in vegan cheese. These are from a different analysis to the one above, but also from the UK.

From this, it seems very likely that cheese substitutes have lower emissions than dairy cheese.

This is obviously very rough. But looking for too much precision is a bit spurious in an area that is this messy, and Joseph Poore may have been right when he said, in response to a question on which is the best plant milk for the environment:

“I think you’re pulling at straws. I think they’re all so low impact compared to dairy milk that if we chose to change to any of them it would generally be beneficial.”

Food Emissions (kg CO2e per kg)
Dairy cheese 18
Coconut 2.1
Tree nuts (almond, cashew etc) 2
Soya beans 2
Soya oil 1.8
Wheat 1
Potato 0.4

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