Imagine you’re a committed climate change campaigner. You’ve just spent a few hours with tens of thousands of like-minded souls, gathering and marching in protest against the fossil fuel sector and governments who pander to it.
You’re confident that you and your friends have made an impact. Media representatives were there, and you reckon you’ll get a minute or two on the evening news and maybe some decent coverage online and in print.
By the time it’s over, you’re tired and hungry, so you head home with your partner and a couple of campaigning pals for a celebratory dinner. You travel from the city to your hip inner suburban neighbourhood by tram, keeping your transport emissions to a minimum. Tomorrow you’ll head back to the city, but you’ll ride your bike for some exercise.
You volunteer to cook, and serve your signature dish of grass-fed beef steak with peppercorn sauce and vegetables. Your partner had offered to cook her favourite spicy sweet potato and bean enchiladas, but you reckon you need a decent dose of protein and iron after all that activity.
You devour your meal, enjoy some chat, then get ready for bed, satisfied with your day’s efforts in helping to save the planet.
But not so fast.
Before you snuggle up for the night, let’s check how you’ve performed in terms of greenhouse gas emissions. We’ll focus on two things; food and transport.
Based on estimates from the Food and Agriculture Organization of the United Nations, by cooking grass-fed steak for four, you may have generated over 200 kilograms of greenhouse gas.
If you’d accepted your partner’s offer to cook enchiladas, the figure would have been around 3 kilograms.
The beef figure is based on the global average emissions intensity of grass-fed beef, allowing for a 20-year time horizon to determine the “global warming potential” of methane and other greenhouse gases. If you live in the United States, Australia or other countries with well-developed agricultural systems, the figure may be lower, but still potentially more than 30 times that of the enchilada option.
How about the tram?
Researchers investigating food’s greenhouse gas impacts, published in the American Journal of Clinical Nutrition, have estimated that the consumption of 1 kilogram of beef is equivalent to 160 kilometres (99 miles) of automobile use. That estimate was conservative for several reasons, but let’s use it in that knowledge.
You traveled 4 kilometres each way by tram, so your total distance of 8 kilometres has prevented greenhouse gas emissions equivalent to consuming 50 grams of steak. That means those steaks (1 kilogram between the four of you) have resulted in 20 times the emissions that would have been generated if you drove (noting that 8 kilometres is one 20th of 160 kilometres and 50 grams is one 20th of 1 kilogram).
The big picture
It’s time you and your friends looked at the big picture of emissions, and stopped slapping each other on the back over your current campaigning efforts.
Sure, it’s essential that we move away from coal and other fossil fuels, but it’s also essential that we move away from animals as a food source.
Or do culinary habits override any desire to retain a habitable planet? (Even relatively low emissions intensity animal-based products may have a catastrophic impact.)
Habits can change with a little effort, so why not try?
Okay, I understand you’re worried about nutrition, but you needn’t be.
Here’s what Australia’s National Health and Medical Research Council says about vegetarian and vegan diets: 
“Appropriately planned vegetarian diets, including total vegetarian or vegan diets, are healthy and nutritionally adequate. Well-planned vegetarian diets are appropriate for individuals during all stages of the lifecycle. Those following a strict vegetarian or vegan diet can meet nutrient requirements as long as energy needs are met and an appropriate variety of plant foods are eaten throughout the day. Those following a vegan diet should choose foods to ensure adequate intake of iron and zinc and to optimise the absorption and bioavailability of iron, zinc and calcium. Supplementation of vitamin B12 may be required for people with strict vegan dietary patterns.”
The Council’s suggestion to supplement vitamin B12 is a more natural approach than destroying rainforests and operating other aspects of livestock production systems. Because of more widespread fortification of foods in the US, the American Dietetic Association didn’t even mention B12 when making a similar statement.
Obtaining other nutrients such as protein, iron, zinc and calcium should also not be a problem. The US Department of Agriculture has shown us some reality by confirming (for example) that soybeans have 35 per cent more protein per kilogram than beef, with all the essential amino acids.
The way ahead
So what’s the next step? It’s simple. Keep campaigning for meaningful action on climate change. All you need to do is broaden your scope by including action on animal agriculture, and preferably modifying your eating habits to be consistent with that approach.
Veganeasy from Animal Liberation Victoria
Vegetarian Starter Kit from Animals Australia
 Derived from Food and Agriculture Organization of the United Nations, “Tackling climate change through livestock: A global assessment of emissions and mitigation opportunities”, Nov 2013, Figure 7 and Table 5, p. 24 http://www.fao.org/ag/againfo/resources/en/publications/tackling_climate_change/index.htm; http://www.fao.org/docrep/018/i3437e/i3437e.pdf and Myhre, G., D. Shindell, F.-M. Bréon, W. Collins, J. Fuglestvedt, J. Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013: “Anthropogenic and Natural Radiative Forcing. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group 1 to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change” , Table 8.7, p. 714 [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, http://www.ipcc.ch/report/ar5/wg1/, cited in Mahony, P., “The Low Emissions Diet: Eating for a safe climate”, 5th February, 2016, , Table 1, p. 6 and Figure 4, p. 7, https://terrastendo.files.wordpress.com/2016/02/low-emissions-diet-4p.pdf
 Myhre, G., et al., ibid. cited in Mahony, P. “GWP Explained”, 14th June 2013, updated 15th March 2015, https://terrastendo.net/gwp-explained/
 Carlsson-Kanyama, A. & Gonzalez, A.D. “Potential Contributions of Food Consumption Patterns to Climate Change”, The American Journal of Clinical Nutrition Vol. 89, No. 5, pp. 1704S-1709S, May 2009, http://www.ajcn.org/cgi/content/abstract/89/5/1704S
 Mahony, P., “The climatarian diet must exclude pig, chicken, fish, egg and dairy”, Terrastendo, 31st January, 2016, https://terrastendo.net/2016/01/31/the-climatarian-diet-must-exclude-pig-chicken-fish-egg-and-dairy/
 National Health and Medical Research Council, Australian Dietary Guidelines (2013), p. 35, http://www.nhmrc.gov.au/guidelines-publications/n55
 Craig, W.J., Mangels, A.R., American Dietetic Association, “Position of the American Dietetic Association: vegetarian diets.”, J Am Diet Assoc. 2009 Jul;109(7):1266-82, http://www.ncbi.nlm.nih.gov/pubmed/19562864
 Mahony, P., “Eating for a safe climate: Protein and other nutrients“, Terrastendo, 12th February, 2016
 USDA National Nutrient Database for Standard Reference at http://www.nal.usda.gov/fnic/foodcomp/search/http://www.nal.usda.gov/fnic/foodcomp/search/ via Nutrition Data at http://www.nutritiondata.com
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