Viva La Vegan!

Previous articles (Part 1 & Part 2) in this series have focussed on the urgent need to meaningfully tackle our planet’s climate crisis.  This article considers some aspects of animal agriculture’s impact.

The world’s pre-eminent climate scientist, Dr James Hansen, says we will not overcome climate change unless we adopt each of the following measures [1]:

  • End our reliance on coal to the extent that it is not captured and stored;

  • Reverse 200 years of deforestation; and

  • Massively reduce our emissions of non-CO2 climate forcing agents, such as methane, nitrous oxide, tropospheric ozone and black carbon.

The second and third measures will not be possible without a general move away from animal products toward a plant-based diet.

Dr Hansen’s approach is summarised in this diagram [i]:


 So what is the problem in using animals as a food source for humans?

The difficulties can be summarised under the following headings which (as indicated) are inter-related:


This article will focus on livestock’s inherent inefficiency, with other aspects of the problem to follow in subsequent articles. This article also considers some aspects of livestock-related water pollution and land degradation.

Inherent Inefficiency

It takes many kilograms of plant-based food to produce one kilogram of animal-based food of comparable nutritional value, with significant impacts on energy inputs, emissions, water usage and land usage.

The figures vary depending on the animal involved, the source of its food, climatic conditions and the like. However, whether it requires two or twenty kilograms of plant-based food to produce one kilogram of animal-based food, the inefficiencies are startling.  That is particularly so when an almost uniform economic creed around the world for decades has been the need for increased efficiency in production, using the mantra of productivity growth.  An example is the Australian Bureau of Statistics 2010 publication “Productivity and Progress” [2].

The following diagram is based on figures outlined in a paper presented at the 2002 Beef Improvement Federation Annual Meeting in Omaha, USA. That paper indicated that it required around 13 pounds of grain, fed to cattle, to produce one pound of meat. [3]


The diagram demonstrates the fact that, for any given quantity of plant-based food, far more people can be fed if that food goes directly to them, rather than via the digestive system of an animal.

Looking at it another way, if we want to feed the same number of people using either production system, the plant based approach will require far fewer resources than the livestock alternative. 


Those resources can be in the form of:

  • land, with clearing for grazing or feed crop production releasing carbon dioxide and creating an ongoing loss of carbon sequestration;
  • nitrogen based fertilizer producing nitrous oxide (around 300 times more potent as a greenhouse gas than carbon dioxide);
  • fugitive methane emissions from fertilizer production;
  • emissions from farming and transportation;
  • pesticides, herbicides and antibiotics;
  • water used and polluted, including oceanic dead zones from nitrogen run-off.

 Water Pollution

In regard to water pollution, the Australian Government’s Great Barrier Reef Marine Park Authority has stated [4], “80 percent of the land adjacent to the Great Barrier Reef World Heritage Area supports agricultural production, primarily beef cattle grazing and intensive cropping agriculture.”

The Authority has also said:

  • “Beef cattle grazing is the largest single land use with approximately 4,500,000 cattle grazing in the Great Barrier Reef Catchment (Department of Primary Industries & Fisheries 1993). Grazing land management has resulted in extensive clearance of vegetation and with over-stocking, particularly during drought conditions has caused widespread soil erosion and the export of eroded material, with its associated nutrients, into the Great Barrier Reef World Heritage Area.” 
  • “Fertilisers and pesticides are taken up by the crop but a significant portion applied to the land ends up in coastal waters. Poor agricultural practice results in soil erosion and the discharge of sediments, nutrients and pesticides into rivers, estuaries and eventually the Great Barrier Reef World Heritage Area.”

Land Degradation

Even if livestock graze native or exotic grasses instead of consuming feed crops, the gross inefficiencies inherent in meat production mean that they degrade massive areas of land.

According to the Australian Bureau of Agricultural and Resource Economics (ABARE): 

“Beef production is widespread across Australia. In northern Australia, production is based mainly on native pastures on large properties; in the southern states, smaller properties with a high degree of pasture improvement predominate. Extensive grazing by sheep and cattle occupies approximately 60 per cent of the rangelands, which in turn represent about 80 per cent of Australia’s land area”. [5]

Accordingly, grazing, with all its destructive qualities (and after allowing for grazing which occurs outside the rangelands), occurs across more than 50 percent of the continent.[ii]

Livestock’s ability to create desert from once-fertile land is outlined as follows [6]:

  • Internationally, severe problems of soil compaction, erosion and decreased soil fertility are being experienced in many cattle-farming areas.  These include the American West, Central and South America, Australia and Sub-Saharan Africa.  The United Nations Environmental Programme (UNEP) estimates that 20 per cent of the world’s grazing lands have been significantly degraded since 1945, with the pace of destruction increasing.
  • Desertification, where land is no longer capable of sustaining food production, affects roughly 50 million acres of the world’s available agricultural land every year, with overgrazing (particularly of beef cattle) a leading cause.  
  • In many parts of the famed American West, overgrazing from the Great Plains to the Pacific Ocean has ground down native grasses and trampled streams.  (Much of the destruction is subsidised by more than $100 million of public money.)  3.2 million cattle are grazed on public lands covering 254 million acres in 17 western states.  A 1999 investigation by a local newspaper, The San Jose Mercury News, summarises the environmental impact:  ‘The lifeblood of the arid West, streams, make up only 1 per cent of the acreage in the 11 Western-most states.  Yet scientists say at least 70 per cent of wildlife there depends on them for survival... Largely because of cattle, only 36 per cent of streams surveyed by the Bureau of Land Management on its public lands in the Lower 48 states are classified as “proper functioning” or healthy... Severely overgrazed streams have trampled banks and little vegetation. Murky, warm water is choked with sediment, algae and manure.’
  • Comparable desertification is also occurring in many poverty stricken areas of the world, where effects on the rural poor are most critical.  Larger livestock populations, partly created by subsidised feed concentrates from wealthier nations, are degrading land in many areas, including ‘the semi arid Sahel, West Asia and North Africa, and the Southern Cone of the Americas’.  

Two further measures of livestock’s inherent inefficiency are:

1. Information reported by Dr David Pimentel, Cornell University, USA in 2003 [7]


We now have more than one billion under-nourished people in the world. [8]  Quite apart from the horrendous environmental impacts of livestock production, the willingness of the wealthy to allow others to starve while plant production is channelled through livestock is morally repugnant.

2. Net Primary Productivity [9]:

Two teams of Austrian researchers have shown that humans in 2000 appropriated 23.8 percent of the planet’s net primary productivity or annual plant growth. Of that amount, around 30 percent was used for paper production, construction and the like. 58 percent was fed to livestock and supplied 17 percent of human-kind’s global food calories. Only 12 percent was consumed directly by humans, providing 83 percent of calories.

If an individual business was operating with the level of efficiency demonstrated by the Austrian teams’ work, it would almost certainly be closed or its methods radically overhauled.

How is it that we allow these levels of inefficiency in such a massive and critically important operation?

Here’s how the comparison looks diagrammatically:



We are running out of time to avoid the catastrophic effects of runaway climate change.  Subjects such as diet must not be regarded as taboo, and must feature heavily in the choices that we make in order to save our planet for all species and future generations. 

Next article: We will look at the scale of the livestock industry and the resultant impacts in terms of deforestation.


Paul Mahony is a member of VegetarianVictoria, Animal Liberation Victoria, Animals Australia and Bayside Climate Change Action Group (BCCAG). In 2009, he prepared Vegetarian Victoria’s submission to the Victorian State Government in response to its Climate Change Green Paper. His question on animal agriculture and climate change finished second in polling for The Sunday Age’s 2011 “Climate Agenda”, and was followed by a major article on the subject. He is also contributing to the land use component of “ZCA 2020”, a project by Beyond Zero Emissions.


[i]       Although the comments on animal agriculture are ours, Dr Hansen has said that in our personal lives, the most effective measure we can take to curb global warming is to begin to alter our diet more toward vegetarian.  However, it should be noted that he also believes that the most effective measure overall is to “support a moratorium, and eventual phase-out, of coal-fired power plants.” [10]

[ii]      For a map based on ABARE’s definition of the rangelands, please see (accessed 3 March 2012), which shows that grazing in all of Victoria, most of New South Wales, around one third of Queensland and portions of Western Australia and South Australia is additional to the figures referred to above.


[1]      Hansen, J; Sato, M; Kharecha, P; Beerling, D; Berner, R; Masson-Delmotte, V; Pagani, M; Raymo, M; Royer, D.L.; and Zachos, J.C. “Target Atmospheric CO2: Where Should Humanity Aim?”, 2008, (accessed 3 March 2012) and Hansen, J., “Storms of my grandchildren”, 2009, Bloomsbury, p. 51.

[2]      Australian Bureau of Statistics, 1370.0 - Measures of Australia's Progress, 2010, “Productivity and Progress”, 15th September, 2010,!OpenDocument (accessed 3 March 2012)

[3]      Derived from W.O. Herring and J.K. Bertrand, “Multi-trait Prediction of Feed Conversion in Feedlot Cattle”, Proceedings from the 34th Annual Beef Improvement Federation Annual Meeting, Omaha, NE, July 10-13, 2002, (accessed 3 March 2012), cited in Singer, P & Mason, J, “The Ethics of What We Eat” (2006), Text Publishing Company, p. 210

[4]      Australian Government Great Barrier Reef Marine Park Authority, (accessed 3 July 2008 but no longer available). See also: Great Barrier Reef Marine Park Authority, “Environmental Status: Water Quality” (accessed 3 March 2012) and J. Brodie, C. Christie, M. Devlin, D. Haynes, S. Morris, M. Ramsay, J. Waterhouse and H. Yorkston, “Catchment management and the Great Barrier Reef”, pp. 203 & 205, Water Science and Technology Vol 43 No 9 pp 203–211 © IWA Publishing 200, (accessed 3 March 2012)

[5]      Australian Bureau of Agricultural and Resource Economics (ABARE), “Agricultural Economies of Australia & New Zealand: Beef Industry Overview”, (accessed 9 July, 2008 but no longer available)

[6]      “The Global Benefits of Eating Less Meat”, Compassion in World Farming Trust, 2004, pp. 38 & 39, (accessed 3 March, 2012)

[7]      Pimentel, D. & Pimentel M. “Sustainability of meat-based and plant-based diets and the environment”,  American Journal of Clinical Nutrition, Vol. 78, No. 3, 660S-663S, September 2003, (accessed 3 March 2012)

[8]      Food and Agriculture Organization of the United Nations Media Centre, “1.02 billion people hungry”, (accessed 3 March, 2012)

[9]      Fridolin Krausmann, Karl-Heinz Erb, Simone Gingrich , Christian Lauk , Helmut Haberl, “Global patterns of socioeconomic biomass flows in the year 2000: A comprehensive assessment of supply, consumption and constraints”, Ecological Economics, Volume 65, Issue 3, 15 April 2008, Pages 471–487, and Helmut Haberl, K. Heinz Erb, Fridolin Krausmann, Veronika Gaube, Alberte Bondeau, Christoph Plutzar, Simone Gingrich, Wolfgang Lucht, and Marina Fischer-Kowalski, “Quantifying and mapping the human appropriation of net primary production in earth's terrestrial ecosystems”, PNAS July 31, 2007 vol. 104 no. 31 12942-12947, Both articles cited in Russell, G. “Burning the biosphere, boverty blues (Part 1)”, 5 January, 2010,

[10]    Hansen, J, cited in Submission to the Garnaut Review by Geoff Russell, Peter Singer and Barry Brook,

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