Enough land for the growing livestock population?

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World population growth has been a hot topic for a long time. According to the United Nations the world population is expected to reach almost 10 billion by the year 2050, which would put further strain on our already overpopulated Earth. However, there is another rarely discussed population growth taking place, namely the growth of farmed animals.

Meat consumption is expected to grow by 76% by 2050, mainly in ‘developing countries’ that are reaching higher standards of living year by year. A study on global biomass distributions estimated that 60% of all mammals on Earth are livestock, compared to 36% being humans, whereas 70% of all birds are chickens and other types of poultry (Figure 1). Thus, the majority of mammals and birds are bred for human consumption, but how many farmed animals are there?

Figure 1. The global biomass distribution between the most populous groups of organisms (Source: Guardian)

The estimation of the total number of farmed animals varies between studies, which has caused confusion in estimations on the overall environmental impacts of our food systems. The difficulty in estimating the total number has resulted in claims ranging from 21.7 to 50 billion farmed animals raised per year. The confusion might also be partly attributed to the substantial increase in the livestock population that has occurred in late 20th and early 21st century. According to a recently published paper in the journal Climate Policy, we have reached the highest number of livestock animals ever recorded - 28 billion farmed animals of which chickens account for more than 80% (Figure 2). Hence, farmed animals far outnumber the global human population, and since the numbers are expected to grow, will it be possible to sustainably manage this considerable increase?

Figure 2. Total number and distribution of farmed animals between 1997 and 2016 (Harwatt, 2018).

It is not only difficult to estimate the total impact of the livestock industry because of the uncertainties in the total number of farmed animals, but also because of different systems involved in the supply chain as well as the variety of different farm practices. However, several studies have tried to estimate both the amount of land dedicated to the livestock industry as well as the resulting environmental impacts, with varying findings.

Considering the vast amount of farmed animals bred into existence, it comes as no surprise that agricultural lands are "the largest biome on this planet", taking up between 33 and 50% of the ice-free land depending on the study (Figure 3). Around 80% of this agricultural land is used for animal production systems such as grazing land and feed crop production. According to the FAO and the World Bank, meat and dairy production cover as much as 27% of the earth's land cover which corresponds to the total land area of both South and North America (Figure 4).

Figure 3. "Global surface area allocation for food production" (Ritchie & Roser, 2018).

One of the most comprehensive studies on the environmental impact of farming found that 83 % of all farm land is used for both meat and dairy production whereas these industries provide only around one third of protein and around one fifth of calories. In addition, the study claims that more than 76 % of agricultural land could be reduced if we were to stop consuming meat and dairy altogether, and still be able to feed the growing world population. This staggering 3.1 billion hectares of land corresponds to a larger land area than the whole continent of Africa.

But is it really feasible for the whole world to follow a plant-based diet and why is the livestock industry so inefficient and require such vast amounts of land?

Figure 4. "How the world's land is used: Total area sizes by type of use & land cover" (Ritchie & Roser, 2018).

In some parts of the world the consumption of animal products might be a necessity, providing for both livelihoods as well as nutrition. In some of the poorest nations as well as remote regions an increased production of livestock might be the only feasible option to enhance food security. Thus, a plant-based world might not be attainable on a global scale. However, in the richest parts of the world, meat and dairy consumption is increasing despite it not being a necessary requirement of our needs.

The need for more land is not only due to the large number of farm animals that require more space for grazing, but for the production of animal feed. In fact, because of the rise in factory farming less land is needed for grazing, but the more animals we breed into existence, the more land is needed to produce feed. An increase in animal production is responsible for 65% of land use expansion since 1960, and this number is expected to increase. Even though smaller-scale farming can in some cases be beneficial for local ecosystems and the carbon sequestration potential of the soils, the intensification of farming along with the increasing demand for animal products create various environmental burdens, such as tropical deforestation and biodiversity loss.

There might be enough land, but will it be at the expense of important ecosystems?