Posted by Juan Pascual | 19/11/2019
The beef industry’s impact on the planet has been high on the news agenda over the past 12 months. Juan Pascual, Elanco’s Vice President DACH & Southern Europe, sifts through the science to find the facts about beef production.
According to many recent headlines, eating beef is one of the main causes of global warming. So, to stop, or even reverse it, it seems logical that we should reduce our beef and milk consumption.
But I’d urge caution about too reductive a view of this complex problem.
It’s true – cows produce methane, which has a potent greenhouse effect and is one of the key factors that drives global warming. But ruminants are by no means the most significant source. To put things into perspective, of total GHG emissions, methane accounts for 16 per cent.1 And of this total, ruminants contribute a fraction at just 17 per cent.
But what is the methane contribution to global warming? Methane has a Global Warming Potential ranking of 28 – this is compared to carbon dioxide (CO2), which is ranked as 1.2
Released CO2 stays in the atmosphere for more than a thousand years, while methane stays around for 10.3 But this type of benchmarking is measured over a 100-year period and isn’t an appropriate way to measure methane.
Once methane is released it goes through some chemical reactions and becomes CO2. This gas is used by plants, taken out from the atmosphere to be transformed by photosynthesis into cellulose as an integral part of the tissue of plants. That means if a herd doesn’t grow, the impact of this population on global warming amounts to zero.
Conversely, if atmospheric methane is produced by fossil fuels, such as natural gas or fracking, it is not part of the carbon cycle, contributing to the warming of the atmosphere.
Cattle methane emissions vary dramatically across geographies. In the US, there are today fewer dairy cows than in the 1940s – nine million today versus 25 million back then.4 However, milk production is six times higher today than it was then – the dairy industry produces around 50lb per day per cow.
In some countries like India, the figure is much lower, producing on average 6lb of milk per day (and there are some 300 million cows living in the country). It demonstrates the scope to develop animal care programmes, which will significantly reduce the number of animals needed to produce the same or even higher amounts of milk and beef.
Moreover, about 90 per cent of what a cow eats is not edible by humans. Without ruminants, a huge amount of vegetable by-products such as corn stalks, cotton seeds, fruit peels or beet pulp would result in GHG emissions that we currently avoid thanks to cows.
In fact, if all livestock production was eliminated in the US, the net GHG reduction will only amount to 2.6 per cent, according to a study conducted in Arizona University.5
For a sustainable world, the livestock industry must continue to reduce GHG emissions and water use. But the impact of cows on the environment is relatively low and it can be improved. Not all industries can say the same.
1 United States Environmental Protection Agency, global greenhouse gas emissions data: https://www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data(accessed November 2019)
2 Global Warming Potential (GWP) compares the amount of energy absorbed by a given gas for a given period of time and benchmarks it against the same amount of energy absorbed by CO2.
3 Live Science, Greenhouse Gases: Causes, Sources and Environmental Effects: https://www.livescience.com/37821-greenhouse-gases.html (accessed November 2019)
4 Living History Farm: https://livinghistoryfarm.org/farminginthe40s/crops_08.html (accessed November 2019)
5 Robin R. Whitea. Nutritional and greenhouse gas impacts of removing animals from US agriculture. PNAS November 28, 2017 114 (48) E10301-E10308