By Marcus Wilson 11/01/2019 1

“Don’t eat beef.”

Such a statement does not go down well in New Zealand,  especially in Waikato, where the cow reigns supreme.

I don’t say it as someone who wants to peddle a “Meat is Murder” message. I don’t believe that at all. I say it as someone who wants New Zealand to take Climate Change seriously.

Quite simply, producing a serving of beef produces a staggering amount of carbon dioxide, as the diagram here from Poore and Nemecek (2018) demonstrates:

[Source:  ; original data from: Poore, J. and Nemecek, T. (2018). Reducing food’s environmental impacts through producers and consumers. Science 360, 987-992. DOI: 10.1126/science.aaq0216  ]

This might need to be put into more context.  Driving 100 km in my car produces something around 14 kg of carbon dioxide.  One serving of high-impact beef tops this. Even a low impact serving of beef is similar to driving about 30 km in a typical car, carbon dioxide-wise. Or put it another way: about 10 kWh (10 units) of electricity from coal-fired Huntly power station will give about 9 kg of carbon dioxide, a smidgen more than an average serving of beef.

But, one should also observe that meat, in general, is bad news for the Earth’s climate. While beef is by far the largest offender, one should note that plant based-foods, in general, are far better than all animal-based foods. So, while I won’t claim that it is morally wrong to eat meat on the basis of the feelings of animals, as some do, I will claim that it is morally wrong to eat meat, especially beef, (to any substantial degree) on the basis of climate change.

Actually, it is interesting to delve into Poore and Nemecek’s data a bit more.  As well as CO2 emissions, they look at land use, phosphate use & eutrophication, and water use. The variation across a food type from the ‘best’ to the ‘worst’ can be staggering. For example, the median stress-weighted water use for producing one ‘nutritional unit’ of tofu is 20 litres, but the mean is 3 thousand litres!  What this means is that a lot of production requires very little irrigation, while a minority of production requires huge volumes. (It is also an example of why one needs to be careful with quoting medians and means, and how a story can be spun to suit one’s own ends by picking the ‘right’ statistic.) One obvious conclusion that Poore and Nemecek make is that we (as a world) must be smarter in how we use agricultural land and resources

Finally, in relation to my last post, and climate change, it is good to hear that the “right-to-repair” campaign is making some progress, in Europe at least…

The post Why you shouldn’t eat beef appeared first on Physics Stop.

One Response to “Why you shouldn’t eat beef”

  • A little science is a dangerous thing! It appears the writer and the paper he quotes from are only considering one part of the life cycle of the carbon involved in growing food. CO2 is taken out of the atmosphere by plants when they fix it in the biological processes of growth. An animal eats the plant, if it is a ruminant some of the carbon ingested becomes a component in methane, which the animal emits. Over a decade or two years the methane breaks down into CO2 and the process of being used by a plant starts all over again. Stopping eating beef will be of marginal benefit at best. Stopping taking hydrocarbons out of the ground where they have been for millions of years and turning them into CO2 which can last in the atmosphere for hundreds of years is likely to have a far larger effect on global warming