How the ingredients of a ruminant’s diet can help save the world - Part 2
What do we need to do to save the world?
As well as controlling COVID-19, humankind has another two urgent requirements: limiting global warming to less than 2°C and feeding the ever-expanding global population. The global food system is required to feed the 7.8 billion of earth’s citizens. At present a total of 3 billion are receiving either insufficient nutrition or suboptimal nutrition: 925 million lack access to major macronutrients, 1 billion more are deprived of important micronutrients, and a further 1 billion consume calorie dense, nutrient poor diets.
The major greenhouse gasses (GHGs) (Carbon Dioxide, Methane, Nitrous Oxide and Ozone) contribute to global warming and climate change by trapping infra-red radiation within the Earth’s atmosphere. Methane is the 2nd largest anthropogenic GHG; persistence estimates vary, ranging between 9-12 years, in comparison with carbon dioxide’s estimated mean lifetime of over 100 years. Methane also has a global warming potential 25 times that of Carbon Dioxide. Ruminants are the predominant source of methane; with agriculture accounting for 50-60% of methane emissions and nearly one third of all anthropogenic GHG emissions. The dairy sector produces twice the global output compared to that of sheep and goats, and the beef industry produces 2.5 times that of dairy. Up to ten percent of all ingested feed-derived energy may be lost as methane from ruminants, with dietary components largely accounting for the variation in energy loss via methane (with dairy cattle, grazing cattle, and intensive beef finishing cattle varying from 5.5–9.0%, 6.0–7.5%, and 3.5–6.5% respectively. Eighty nine percent of methane is produced in the rumen and emitted through the upper respiratory tract in sheep: the methane itself being produced within the rumen by methanogens, which are a collection of Archaea species.
Half of agriculture’s GHG emissions are an indirect result of land conversion from forest, pasture or wetland to cultivatable ground. Land conversion is a key reason for the disparity in carbon footprint figures given for national and international agriculture, with UK figures approximately half that of global averages. Livestock farming within the UK is often able to make use of marginal or ground sub-optimal for arable cultivation, whereas around the globe, land suitable for crop may be utilised for livestock production. Farming is recognised as a major contributor to biodiversity loss, carbon dioxide release, soil degradation and climate change, with agriculture utilising one third of all suitable land and over two thirds of global freshwater use. Separately, estimates would suggest a third of the global grain harvest is utilised to feed farmed animals as opposed feeding humans directly, which may hinder, rather than help feed the world’s population. Livestock farming is deemed to have a heavier environmental impact when compared with arable agriculture, and this will only be exacerbated by both the ever-increasing world population and the societal change of this population which has increased worldwide demand for ruminant meat products. At current rates by 2050, there is a predicted 73% increase in demand for meat, and 58% for dairy.
It would appear the first principle of farming, ‘never take out more than you put in’ has not always been adhered to, and to avoid Thomas Malthus’s prediction, it is mandatory that agriculture follows a sustainable path allowing for global food security long into the future. This path, as spelt out in the Godfray review, must produce more, but from less land, and with fewer direct negative environmental impacts, balancing both the needs’ of the world’s population with the needs of the world itself. The initial aim would appear achievable, given that until now whilst the world population has nearly doubled, cultivated land has only increased by 11 percent (equating to a 40 percent reduction in land per capita), and further that one third of all food produced for human consumption (1.3 billion tons) is wasted each year. Peer reviewed literature has existed for nearly 30 years describing how we choose to feed ruminants can be part of the solution to reducing these already emphasised deleterious environmental effects. It must be remembered that often the increased food quality which has the ability to reduce ruminants’ methane outputs may be derived from food sources fit for human consumption, so there is potentially a balance to be had between reducing ruminant’s methane output and producing meat and milk to feed the population.