Some people are vegetarians because they believe it is morally wrong to consume other animals. I am not one of these people.  Nature created our species as an omnivorous animal, just as it created deer as herbivores and lions as carnivores. For something like 12,000 generations my Homo sapiens ancestors have been meat eaters. 

The cattle grazing on our farm would not exist if humans didn’t eat meat. They have a good life, and seem to be quite happy most of the time.

However, I feel strongly that we should completely change the slaughtering procedure. Animals should be killed instantly in the paddock or yard on the farm, and then transported to the butchery. None of this trucking long distances to sale yards, and none of the extreme fear as they are lined up for slaughter.

The ecological arguments for vegetarianism, and even veganism, are more persuasive.

The Anthropocene, or Exponential Ecological Phase of human history, has seen big changes in the size of the populations not only of humans, but also of wild and domestic animals.

It is estimated that 12,000 years ago the biomass of vertebrates on Earth was around of 200 million tonnes (mt). Humans made up one thousandth of this amount. Today the vertebrate biomass is about 930 mt, nearly a five fold increase. However, the wild animal component is reduced by 85 per cent (to 30 mt).  Humans have increased 1,500 times (to 300 mt). Domestic livestock bred for food or animal fibre, have increased from zero to 600 mt.[1]

Over 90 per cent of these changes have occurred in the past 250 years of Homo sapiens’s 300,000 years of existence.

            12,000 years ago                2000 AD
Wild animals                 200 mt                    30 mt
Humans                  0.2 mt                   300 mt
Domestic animals                    0 mt                    600 mt

The farming of animals for food production is now on a scale and of a kind that it is causing serious ecological problems worldwide.  For example, in some areas animal farming is causing significant loss of biodiversity. This is especially so in the tropical rain forests of Central and South America, where deforestation to make way for cattle is resulting in the loss of many unique animal and plant species.

Land degradation caused by overgrazing is also a serious problem, especially in dry areas of the world. Impacts include biological impoverishment of the soil, soil erosion and eutrophication of streams and rivers.

According to FAO, livestock, including poultry, account for 14.5 per cent of anthropogenic greenhouse gas emissions (in terms of carbon equivalent). 

A recent paper in the journal, Science, has highlighted the scale and seriousness of the problem, leading the authors to advocate universal veganism to save our planet.[2] They estimate that a vegan world would produce 40 percent less food-based greenhouse gas emissions, 50 per cent less acidification on land, 49 per cent less eutrophication, and would use 19 per cent less water; and it would cut land us by 76 per cent. They point out that there is big variation in the environmental impact of different farming practices. It has been reported that the world’s 10 per cent worst beef producers emit 12 times more greenhouse gas, and takes up 50 times more land, to produce a unit quantity of protein, compared to the best 10 per cent.

Referring to this paper, George Monbiot of the Guardian, writes:

We can neither feed the world’s growing population nor protect its living systems through animal farming. Meat and dairy are extravaganza we can no longer afford.[3]

So, apparently, we have a sad situation.  For some 300,000 years humankind fitted in to the biosphere much like any other omnivorous species, and although there were fluctuations in population from time to time, there were never enough people to threaten the integrity of the ecosystems on which they depended. After the introduction of agriculture around 12,000 years ago, the human population began to increase and there are now 1,500 times as many people on Earth as there were when farming began. At present the population is growing at the rate of around 1.4 million each week.

Perhaps the advocates of veganism are right. The population has now reached such a level that we must stop eating meat, which was such an important part of the natural diet of our species.  We must to shift to an unnatural diet to save the planet, simply because there are so many of us.

Not surprisingly, there has been a backlash from supporters of the meat industry. Critics suggest the paper in Science is too narrow. They ask: Why single out meat production, when there are so many other human activities threatening the integrity of the biosphere? Activities like producing palm oil and soya bean oil and the use of fossil fuels, and even keeping pet dogs and cats, make a huge contribution to the unsustainability of modern society?  They draw attention to the fact that, in some parts of the world, populations depend on meat eating for their very survival, and that well managed grazing pastures can have a positive effect on biodiversity.

In my view, the facts assembled in the Science paper are probably sound, and the production of meat and dairy products, along with various other human activities, is threatening the living systems that underpin our existence.  The crux of the problem is that there are vastly too many humans on Earth.

[1] These figures are based on information assembled by Paul Chefurka (see

[2] J. Poore and T. Nemecek. 2018. Reducing food’s environmental impacts through producers and consumers. Science 360. Issue 6392. Pp.987 – 992. X

[3]  G. Monbiot. 2018. The best way to save the planet? Drop meat and dairy. Farming livestock for food threatens all life on Earth. The Guardian Weekly. 199. No.2 p.48.

One thought on “Vegetarianism

  1. 1. Eliminating meat from our diets won’t solve the problem, but reducing meat consumption and producing meat only where it complements but does not replace food crops will help. Animals have been and can be part of sustainable agriculture and human nutrition. And I’m not a ‘supporter of the meat industry’. I agree that animals can be killed ethically or unethically. However, even given the overconsumption of animal products by rich people (a large and increasing proportion of the world’s population, including me), the environmental effects of that are small compared to those of the quantity, diversity and convenience of food and beverages we expect everywhere all year-round, not to mention transport (fossil fuels), accommodation (concrete, steel, timber) and other amenities we enjoy, even for those of us living modestly by rich-country standards.
    2. Including wild vertebrates in the discussion is not that helpful; if such a figure is to be included then a more appropriate biomass would be that of all heterotrophs, which I suspect would be far larger than 200 or 30 million tonnes (Tg) and much more difficult to estimate and compare over time.
    3. The environmental desirability of meat consumption is worth discussing, and so is the relative desirability of plant-derived foods. However, it’s not correct to assume that palm oil or soybean oil are less environmentally desirable than other foods. Humans need a certain amount of fat, and vegetable oils are a good source. Oil palm is the most efficient and feasible converter of sunlight into edible oil that we have. Soybean produces far less oil, but it is a very efficient producer of protein. The problem is not with these crops, but with some of the places and ways in which they are cultivated. Vegetable oil consumption is increasing with population growth, but at a slightly higher rate, as people get richer and consume more manufactured foods, soap, cosmetics etc. The problem of tropical forest clearing is due to rising demand for timber and all agricultural products, but it is also partially due to a decrease in the area of agricultural land in rich countries over recent decades, which is related to people in rich countries not wanting to be farmers (abandoning farms), and wanting farming land converted to conservation areas.
    4. If we want our children to live in a global environment like we know existed not long ago (I certainly do), then there are indeed too many humans on earth, but there is a small light at the end of the tunnel. In our lifetimes, population growth has slowed from exponential to linear and, according to the UN projections, the growth rate will most likely decline to zero somewhere within the next 50-100 years. In other words, a really important inflection point in population and hence human impacts on the environment is happening around now. And we’ve all done our bit by having less children than our parents. But yes, there’s a lot more we need to do!


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