We love our meat, but our meat does not love the Earth. Humanity’s enduring love for livestock, and livestock above all other agriculture, is conspiring to upend Earth systems. A review of the academic literature demonstrates with overwhelming certainty that livestock are the largest driver of pretty much every harm to the biosphere: biodiversity and wildlife loss, species extinctions, deforestation in biodiversity hotspots, waterbody pollution and freshwater scarcity. It is not hard to see why this is, land devoted to farmed animals is greater than all other human land-uses combined, and farmed animals and the industry surrounding them replace, usurp and compete directly with other wildlife, leading to degradation and depletion of wild animal populations and the habitats they live in. Furthermore, and this is astonishing, since livestock are a larger consumer of human-edible crops than humans are, they are responsible for more insecticide, pesticide, artificial fertiliser and herbicide use than crops directly eaten by humans. This is just the environmental chaos livestock wreak; farmed animals are also the largest consumer of human-grade antibiotics, meaning that they are a leading cause of antibiotic resistance. Should these impacts be tolerated as they are? I think not.

If you are a meat-eater you probably believe that the problem is not in the eating of meat per se but in how the meat you buy is produced and sourced; the how, not the what. Your belief is a belief widely shared and is what has powered the progressive campaigns and development of industry standards to improve livestock production. These standards have been atavistic in that they have sought to take a dirty, polluting industry of the modern age and revert it to the gently idyllic produce of a former, more sensitive world. The essence of this movement has been captured in the marketing of meat products advertised as grass-fed, free-range, organic or high-welfare, and these products have enjoyed endorsement and sponsorship from many environmental organisations.

Those who have supported these agricultural reforms have been right to lament the scourge of the industrial livestock farm, but the new models of agriculture they envisage replacing the intensive lot will not resolve this environmental catastrophe, and a world filled with these farms may pose an even bigger risk to nature than the industry they have been aiming to replace. How can this be so? The answer is somewhat mathematical: it boils down to a formula of yield, consumption and land area. The intensive factory farm is that much more efficient on average in terms of land-use and resource input for a given volume of meat, whereas extensive farming models are lower-yielding, requiring much more pasture to produce the same yield. A recent Harvard University study published in Environmental Research Letters predicted that if the US were to turn all of its intensive livestock systems into atavistic models under current meat consumption levels, then it’s entire landmass would have to be converted to farmland. Let that sink in for a moment; a world of free-range, organic and grass-fed animals would result in no space for wild or semi-wild terrestrial ecosystems, and of course, no space for humans.

This model output doesn’t only indict the gluttony of the American diet, other high-income nations, including the UK, would also certainly see almost all remaining nature reserves grubbed out in the face of any major extensionist agricultural reforms. Further still, mounting scientific evidence is demonstrating that extensive livestock production systems would still be net contributors to climate change and biodiversity loss, really bringing into question whether these were ever proffered as evidence-based solutions to environmental harm, or really were just nostalgic pursuits vying against the onslaught of a harsh, industrial world.

The reality is that, at present, the vast majority of livestock farms are intensive systems, and these are not going anywhere fast. In fact, in it’s recent roadmap plan to end hunger whilst aligning the food system with environmental goals, the United Nations Food and Agriculture Organisation primarily advocated to intensify and increase the efficiency of lower-yielding (i.e. extensive) systems in developing countries to replicate the operations of the US and Europe. If this sounds disconcerting, it is because it is. The UN FAO’s roadmap offers nothing more than a ramping up of the impacts that I outlined in the opening paragraph, plus many more horrors for a growing numbers of animals living in the most confined, caged and desperate conditions.

It might seem by now that humanity has locked into a careening spin down the gutter. There is hope of course, and whilst the escape from the spiral won’t be easy, it will be really very simple: significantly reduce global production and consumption of animal products. Reducing animal product consumption is the only pathway humanity can devise to engineer the degrees of freedom necessary to act both healthily and sustainably.

Here is why: pasture and grassland for livestock rearing occupy nearly a third of the earth’s land-area, as mentioned, a land-area greater than all other human land-uses combined. In a pathway with significantly less farmed animals, there would be less land devoted to them. Because there would be less land devoted to livestock, there would be less use of both land devoted to animals and the crops that feed them. Because less land would be under agriculture, significant tracts of land could open for alternative, sustainable land-uses: wildernesses, nature reserves, protected areas and untampered ecosystems, and even housing (not sustainable, but nonetheless constrained by available land-area). And that’s not all; because there would be significantly less land under agriculture, there would be more scope to accommodate the increasing land-use requirements of a growing human population who require feeding, housing and clothing. Finally, animal welfare concerns could be seriously addressed by upping the proportion of extensive farms, without competing so severely with other land-uses. Remember, the scenarios I outline here cannot play out under continued or increase demand trajectories, demand and supply have to drop together, by 50-80%.

Let us consider how these reductions should be distributed. In order to ensure consumption and production reductions occur equitably, high and middle-income countries who consume the most meat must do the heavy-lifting and reduce consumption of meat drastically; this will afford low-income countries modest rises in livestock consumption in order to combat nutritional deficiencies.

You might be wondering whether humanity could even shoulder such big changes in diet. Does this not bias the solution heavily toward nature and leave humanity languishing, anaemic and undernourished?

In 2019, the EAT-Lancet commission, a research team made up of 37 world-leading scientists in environmental, nutritional, and agricultural disciplines, set out to explore an analogy of this exact question. They were tasked with researching whether the world could feed the projected 10 billion people inhabiting it on a healthy diet and within planetary boundaries. Their conclusion was yes, it is possible, but only if there was a global, drastic, and sustained cut in meat consumption. 

The research team calculated the model sustainable and healthy diet. Amongst reductions in sugar intake and increases in vegetables, legumes and nuts, the diet only contained 85g of meat per day, demonstrating that the average person is drastically over-consuming meat, in ways that are almost certainly unhealthy. The model diet contained only 14g of red meat (both beef, lamb and pork) per day, amounting to only 2 sausages a week and absolutely no other red meat. It also contained 29g of chicken and fish per day, amounting to only one and a half chicken breasts and sea-bass fillets per week. Perhaps reassuringly for some, the diet contains 250g of dairy products a day, which is enough for a small glass of milk.

Let’s get down to brass tacks and explore what this mean for you. If you live in the West and eat two to three meals or snacks a day with a significant animal product component, then you can drop this quite significantly whilst increasing consumption of nuts, legumes and vegetables and feel no harm to your health. If you have milk with cereal you could replace this with a plant-based milk and stick to dairy milk in your tea. If you eat meat twice or three times a day, you can reduce this to three moderate portions a week with small amounts of dairy each day. Indeed, if you feel strongly enough and wish to make a bigger impact, then you can almost certainly become a vegetarian or vegan without any impact on your health. What really needs to be underlined is that production systems cannot become sustainable without reductions in consumption, someone somewhere has to reduce their intake.

These findings should be exciting. They mean that meat can still remain an important and regular part of our culinary and food culture and that legacies and histories can be maintained for farmers and consumers alike. Meat can still help to fortify diets with a good source of protein but new opportunities will open up to explore an new world of diverse and healthy foodstuffs. It also means, crucially, that Earth systems – our society – can be given it’s only fighting chance of continuing as we know it or once knew it. Five years ago I took the decision to reduce my consumption of animal products from every meal to about one in six meals; there was negligible impact on my health, but an incredible depth of good-feeling knowing that my simple decision was the only one consistent with a sustainable future for the creatures and habitats of Planet Earth.