What type of cheese has the lowest carbon footprint?

Question

An answer to a question about the carbon footprint of cheese inspired this question.

According to Wikipedia, cheese can be made from the milk of several animals:

• cows
• goats
• sheep
• buffalo
• reindeer
• yak
• donkey
• moose
• camel

Another key ingredient in cheese making is rennet, which can be made from animal, vegetable, and/or microbial sources. For this question I am not concerned with the environmental impact of rennet, assuming that its carbon footprint can be calculated separately from that of the rest of the cheese production process.

So, which type of cheese has the lowest carbon footprint? Is it simply a factor of which type of livestock has the lowest carbon footprint, or are other factors involved?

Answer 1

Recently reported research carried out by Rocky De Nys of James Cook University, Australia, has found that a 2% seaweed feed supplement for cattle substantially reduces the methane production in cattle rumen, thereby reducing the greenhouse gas emission of cattle.

I suggest that you use seaweed fed cows' milk to make your cheese.

Popular article: Feeding cows seaweed could slash global greenhouse gas emissions, researchers say

Research paper: Seaweed as a protein source for mono-gastric livestock

Abstract:

Here, we critically appraise the literature and quantitatively assess seaweeds as a protein source in livestock feeds by assembling a database of amino acid data for 121 seaweed species and comparing the quality and concentration of protein to 'traditional' protein sources (soybean meal and fishmeal) and then benchmarking the seaweeds against the amino acid requirements of mono gastric livestock (chicken, swine and fish).

Key findings and conclusions: The quality of protein (% of essential amino acids in total amino acids) of many seaweeds is similar to, if not better than, traditional protein sources. However, seaweeds without exception have substantially lower concentrations of total essential amino acids, methionine and lysine (on a whole biomass basis, % dw) than traditional protein sources. Correspondingly, seaweeds contain an insufficient concentration of protein, and specifically insufficient essential amino acids, to meet the requirements of most mono-gastric livestock in the whole seaweed form. Consequently, the concentration or extraction of protein from seaweeds will be the most important goal in their development as an alternative source of protein for mono-gastric livestock.

Answer 2

Vegan cheese has the lowest carbon footprint

First, let's take a look at cheese from dairy milk. Let's go with the lowest estimate and say that cheese has a carbon footprint of 5.13 kg CO2e/kg yield.

For cheddar, as sold at retail (63.2 % milk solids), the carbon footprint using the IPCC 2007 factors is 8.60 kg CO2e/kg cheese consumed with a 95 % confidence interval (CI) of 5.86–12.2 kg CO2e/kg. For mozzarella, as sold at retail (51.4 % milk solids), the carbon footprint is 7.28 kg CO2e/kg mozzarella consumed, with a 95 % CI of 5.13–9.89 kg CO2e/kg.

Source: Life cycle assessment of cheese and whey production in the USA

Now let's consider two different vegan cheeses with two different compositions. First up is Miyoko's cheese where the main ingredient cashews, has a carbon footprint around 2.3 kg CO2e/kg yield. This is likely to represent an upper bound because adding water (second ingredient) reduces the carbon footprint per kg of yield.

Miyoko's - Organic Cashews, Filtered Water, Organic Coconut Oil, Organic Parsley, Organic Rice Miso (Organic Rice, Water, Salt, Alcohol, Koji Culture), Organic Garlic, Organic Herbs, Sea Salt, Nutritional Yeast, Cultures.

And let's look at Daiya cheese. One life cycle analysis of cassava starch found that dry starch (like tapioca starch) had a footprint of 0.594 kg CO2e/kg yield. Again, this is likely to represent an upper bound because the first ingredient is just water. Vegetable oils (canola/safflower) can get as high as 4 kg CO2e/kg yield, but even if Daiya was made of 100% oil it would still be less than dairy cheese.

Daiya - Filtered water, tapioca starch, coconut oil, vegan natural flavours, pea protein isolate, non-GMO expeller pressed: canola and/or safflower oil, chicory root extract, sea salt, xanthan gum, lactic acid (vegan), tricalcium phosphate, pea starch, potato protein, vegan enzyme, cane sugar, annatto (colour), coconut cream

Answer 3

There is an extensive study by the UN Food and Agriculture Organization: Tackling climate change through livestock. Their key facts and findings summary has a comparison between cow and small ruminant (i.e. sheep and goats) milk.

The comparison is done in terms of kg of CO2 equivalent emissions per kg of milk protein produced. The conversion from milk to cheese does not add significantly to the emissions measured against the protein content, so these figures can be taken as indicative.

The FAO study finds that, on average, small ruminant milk has higher equivalent emissions, at 112 kg CO2e/kg milk protein, than cow milk (below 100 kg CO2e/kg milk protein). They also note that there is large variability depending on farming techniques used.

Options for reducing emissions of methane (added Feb 15th).

A report from the BBC suggests that changing the diet of dairy animals can reduce their oral methane emissions. These emissions arise from a group of archaea (single cell organisms) living in the cows gut, and can be reduced by either changing diet or reducing the archaea population medicinally -- but either method can also reduce milk production -- so it appears that more research is needed.

At the other end of the animal, it is possible to reduce emissions by collecting and treating the feces, as described in this paper on "Green Cheese". This gives a significant reduction, but the carbon footprint is still going to be significantly higher the vegetable sources of protein.

Answer 4

For cheese, begin with milk.

And the largest dairy farms are going to have the economy-of-scale to make methane-capture both possible and profitable.

Methane can be captured at indoor milking stations. And cow manure in the fields can be put into digester tanks that have inflatable rubber bladders on top and capture methane.

Of course there is no 100% capture of methane unless the cows are kept indoors all the time.

Now the captured methane as an energy source is just two uses of the methane. Otherwise the methane could be used to make plastic for use in long-term building materials.

Answer 5

This answer is not very scientific. but the closer you get to the cheese maker and the closer that cheese maker is to the milk supplier, the lower the carbon footprint.

You could buy a cheese made with the lowest carbon impact ever, but if that cheese is transported using petrochemical, or even electrical car, the carbon footprint will shoot right up.

It's the distance the cheese traveled and not really how it was made. Especially if the cheese came from overseas.