Good question. Ruminant meat is correctly being criticized because of its heavy land, water and GHG impacts. It is one of the least efficient foods to produce when considered from a “feed input to food output” perspective. Because of this, ruminant meat requires more land and freshwater and generates more greenhouse gas emissions per unit of protein than any other commonly consumed food. Full transparency here, I have been one of those critics. See the following report.

Technical Report Shifting Diets for a Sustainable Food Future

Now to your question about the benefits of ruminant meat. There are of course many. First, in places where there are native grasslands, it makes good sense to use these for livestock production. But note that nearly all the world's native grasslands are already used, so any further increases in ruminant consumption will drive further expansion of pastureland into natural forests and savannas. Second, ruminant products, including dairy, provide a concentrated source of vitamins and minerals that are particularly valuable to young children in developing countries whose diet is otherwise poor. Studies have demonstrated large benefits from modest increases in meat in the diets of the poor in sub-Saharan Africa. Third, in many poor countries livestock are an important source of household income. A survey of 13 low-income countries in Asia, Latin America, and Africa found that livestock provided 10–20 percent of the average income of rural households in each of the lowest three of five income categories (see the above report for the citation) For these reasons, World Resources Institute (where I work) has focused its recommendations on reducing ruminant meat consumption to regions with high levels of consumption. And even in these high-consuming regions we still allow for some consumption, just less, give the water, land, and GHG intensity of producing it. In a world of 9+ billion we will be in serious trouble if everyone consumes ruminant meat at the same per-capita levels of North America and Europe.

In case it is of interest WRI just published a report on how to sustainably feed the population in 2050:

Technical Report World Resources Report: Creating a Sustainable Food Future

Article How to Sustainably Feed 10 Billion People by 2050, in 21 Charts

You can also read a summary blog that outlines the menu of solutions from the above report in 21 charts.

Hope this is of some help. Thanks for reading.

Ruminants consume and digest many feeds and food-byproducts that otherwise would not be used to produce food. For example, ruminants consume citrus pulp, sugar beet pulp, almond hulls and many similar products. Ruminant meat from species that are primary milk producers such as dairy cows, goats and buffalos has a significantly lowere GHG load because the milk-producing animal delivers young that can be used to produce beef, particularly if the your are males. If one looks at the global population of cattle, many have very low productivity and this exacerbates the problem, because these poorly-productive animals have very high GHG load per unit of protein that can be consumed by humans. As mentioned by Janet Ranganathan , cattle and other ruminants often represent a households savings and can be converted to cash quickly. Ruminants also provide power for cultivation and other farming needs and their manure is a valuable source of fertilizer. If productivity could be increased, it would be possible to reduce the number of ruminants substantially and still meet the needs of society. In the USA, more small farmers produce cattle than any other commodity or crop. It is the small farmers that will be displaced as ruminant numbers decline.

In livestock production, the overriding considerations are the availability and efficient use of local natural resources. A successful livestock development strategy requires the formulation of resource management plans that complement the wider economic, ecological and sociological objectives. Particular attention needs to be given to land-use systems and to the natural resources required for improved livestock production. The strategy will also need to consider the social, cultural, political and institutional elements that affect the management of natural resources. On the policy side, issues relating to land use, common property, legislation, price policies, subsidies, levies, national priorities for livestock development and research capacity have to be addressed. Finally, the implementation of action programmes requires both technical and institutional support and, equally important, government commitment. Livestock are important contributors to total food production. Moreover, their contribution increases at a higher rate than that of cereals . Recent increases in livestock products appear to be even more spectacular than those achieved for cereals from the green revolution. Most notably, egg production has increased by 331 percent over the last two decades, compared with 127 percent for meat production, 78 percent for cereals and 113 percent for fish (equivalent to 58 percent of that of meat production).

Per caput consumption of animal products

Given the low per caput intake of animal products in developing countries compared with that in developed countries (Table 4), there is considerable potential for increasing consumption and, hence, production of animal products (milk and meat) in these countries. An enormous number of poor people in developing countries cannot afford to include animal products in their diets - they are vegetarians by necessity rather than by choice.

Per caput nutrient supply in developing countries

Calories. Animal products are primarily a source of proteins and essential amino acids, but when they are a major constituent of the human diet they also contribute a significant proportion of total calories. In developed countries they provide more than 30 percent of calories in the diet . In developing countries, however, this proportion is less than 10 percent, but they are a source of essential amino acids that balance the largely vegetable-based proteins.

Proteins. In developed countries, about 60 percent of the dietary protein supply is derived from animal products, which is higher than necessary for essential amino acids. This figure is only 22 percent in developing countries, which is less than desirable and takes no account of the skewed distribution in favour of the middle classes - the poor actually have a much lower protein intake. In these countries, where diets are composed of only a small number of staple foods, animal products are of great importance in preventing malnutrition as they are concentrated sources of the limited essential amino acids available in vegetable proteins of staple foods.

Fats. Excessive consumption of calories, particularly fat from animal products, is often the cause of human health problems, especially in wealthy societies. Figure 2 clearly demonstrates that excessive consumption of animal fat is not a problem for people in developing countries. In fact, animal fats complement an often-deficient calorie intake.

Livestock help to alleviate seasonal food variability. Even though milk production is seasonal and surpluses cannot be stored as easily as cereal grains, there are simple technologies that allow herders to keep milk products for weeks or months in the form of clarified butter, curds or various types of cheese. Animals, particularly small livestock, are slaughtered as the need arises. Meat preserved by drying, salting, curing and smoking can be used when other food sources are scarce.

Animal products not only represent a source of high-quality food, but, equally important, they are a source of income for many small farmers in developing countries, for purchasing food as well as agricultural inputs, such as seed, fertilizers and pesticides.

At the national level, livestock food products represent 27 percent of the total agricultural output. This subsector has achieved the greatest growth in production over the last three decades, and it is expected that it will continue to grow faster than all other agricultural subsectors in the next 20 years (Table 5). The total value of milk and meat represents 3.5 times the value of wheat and rice and 2.8 times the value of fish (Table 6). In addition, there are various other products and services provided by livestock that are not accounted for in these statistics, but which would increase the total value of livestock considerably.

At farm level, cash can be generated regularly from direct sales of livestock products, such as milk, eggs and manure, occasionally from the sale of live animals, wool, meat and hides and from fees for draught power or transport services.

An important feature of dairy income is its regularity. India's dairy development programme Operation Flood has created cooperatives that pay daily for the milk delivered, thereby providing regular income to thousands of poor farmers. An FAO/United Nations Development Programme (UNDP) dairy project in Burkina Faso assisted 100 families in increasing their monthly income by about US$80, which is equivalent to an extra labour unit per family. In many countries, the provision of animal draught power services for cultivation, transportation and the pumping of irrigation water is an important source of income that is particularly beneficial to landless owners of cattle or buffalo.

Livestock also provide increased economic stability to the farm or household, acting as a cash buffer (small livestock) and as capital reserve (large animals), as well as a deterrent against inflation. In mixed-farming systems, livestock reduce the risks associated with crop production. They also represent liquid assets that can be realized at any time, adding further stability to the production system.

The importance of livestock as a source of income for poor farmers is illustrated by the example of the Grameen Bank in Bangladesh, which assists only the poorest segment of the population and provides about 50 percent of its loans for the purchase of livestock, mainly large ruminants for milk production and draught power.

Livestock as a generator of employment

At farm level, dairying is a labour-intensive activity, involving women in both production and marketing. Labour typically accounts for over 40 percent of total costs in smallholder systems. It has been estimated that for each 6 to 10 kg of additional milk processed per day in India, one working day is added for feeding and care. Data from Kenya show that smallholder production there is in the order of 25 kg per working day; similar levels were experienced on parastatal dairy farms in Zimbabwe.

Goat, sheep, poultry and rabbit husbandry, especially in backyard production systems, provides an important source of part-time job opportunities, particularly for landless women and children.

The livestock-product processing sector has also been identified as a contributor to employment generation and the reduction of rural depopulation. Small-scale milk processing/marketing is labour-intensive (50 to 100 kg per working day) and generates employment and income from the local manufacture of at least part of the equipment required. The meat sector also provides significant employment opportunities. Based on UN published data and experience from FAO projects, estimates have been made of labour requirements in small to medium-sized slaughter and meat processing operations

Thanks for your in-depth and considered answers. Are their better types of ruminant production eg feeds to ruminants that dont displace or use human suitable feeds. Also are methane and nitrous oxide emissions from ruminants truely antropogenic as they have been around for 20 million years well before humans ? Its just the numbers that are the issue. Also the religious significance in many countries eg India.

The concerns to the impact on GHG and with that its carbon footprint are real and a driver for many concerned people. However, it must be seen in its proper context and some of the concerns are based on a misinformed opinion without consulting source materials first. The fifth assessment report of the IPCC is good document to get your teeth into (https://www.ipcc.ch/site/assets/uploads/2018/02/SYR_AR5_FINAL_full.pdf). In short livestock production contributes about 6% to the total GHG equivalent produced per year. Any study should also include a proper presentation of facts without mitigating the responsibility of livestock production to limit its contribution to the GHG pool. The notion on one of the gases (CH4) that it is more lasting than the others, is addressed in the report, and it is expected that the methane will not increase that much (high confidence according to the report). In Southern Africa that are large parts of land that is used for ranching with game and as nature reserves, projects are underway to estimate its contribution to the GHG. In rural areas of South Africa livestock ownership is also seen as a status symbol where the number owned is more relevant than the quality thereof.

Look at the ATTACHED image. It shows GHG changes over time, all expressed as as CO2 equivalents. You can clearly see that the rise in methane is meager compared to the rise in CO2.