Sunday, 5 January 2020

Beefing about meat

You may be sick and tired of hearing that we all need to reduce our meat eating because of climate change, especially beef. Most people like eating meat and learning how to use alternatives is not easy, though more and more convenience foods are now available. Anyway, the NFU tell us that farming can be carbon neutral [1]. So what is the problem? Here I go through some of the arguments.

Is it true that UK beef is so much better than the global average?

Yes it is certainly true that UK beef is several times better than the global average. This graph comes from an FAO report from 2013 [2]. It does not show the UK separately from Western Europe but there is not much difference. (There have been smaller studies since. A huge international meta-analysis published in 2018 also found a similar range between best and average across different regimes. However, these were not reported by region or country [3].)
Comparing carbon emissions from beef production in different parts of the world from [2]

This shows:
  • Meat emissions intensity (emissions per unit weight) in Western Europe is around 40% of the global average
  • The main components of emissions are enteric methane (belches), manure (including that deposited on pasture) and production of feed
  • Emissions from manure and from enteric methane are a third to a half the global average. Also in this region there is very little emissions from land use change i.e. deforestation for increasing land for pasture or for growing feed.
In the same report the FAO indicates two main main reasons for high efficiency. Firstly, good quality forage and feed enables the animals to grow quickly, producing less manure and less gas from digestion. Secondly, integrating the meat and dairy systems is more efficient. This is because the meat industry uses calves (including almost all the males) which are produced but not needed by the dairy industry. Western Europe is also more productive on the dairy side compared to the global average, but the difference is smaller; the emissions are about 60% of the global average.

How does beef compare to other meats, in the UK?

From the same report, again assuming the UK is similar to Western Europe, the emissions from European chicken and pork are about a third of those from European beef. Lamb is similar to beef.

Partly this is due to chickens and pigs producing hardly any methane. They also are relatively efficient at converting feed into meat. However, they also are given much more specially grown feed: a quarter to a half of emissions from pork and chicken are due to imported soy feed triggering deforestation in other countries.

Do grass fed cattle produce less emissions?

The GHG emissions from cattle grazing on pasture are low compared to growing feed crops. However, grass is not as not as nutritious as concentrated feed, so the cattle have to eat more, producing more manure and methane on the way. This is worse if the grass is not good quality, which is one reason why emissions are so variable between different parts of the world. In practice, mixed systems involving some concentrated feed tend to be most efficient.

Can we reduce carbon emissions from manure handling?

When animals graze on pasture their manure is spread naturally and emissions are relatively low. However when animals are kept indoors or in small paddocks the manure needs special handling to reduce environmental impacts in general – not just greenhouse gases. Even grass fed cattle generally come inside for the winter so this applies to them too.

As of 2017, the emissions from manure handling in the UK (all animals) were about 7 Mt CO2e (of which nearly half due to cattle). Manure deposited on pasture added another 1 Mt CO2e [4]. We cannot do much about the latter but for the manure that is collected and managed, treatment with an anaerobic digestion can convert it to methane gas (for energy) and fertiliser. This could reduce emissions from manure by around 20% [5]. These digesters can be profitable too, at least when used on a large scale. It helps - but is not a panacea.

Can we reduce enteric methane emissions from cattle and sheep?

There has been a huge effort going to reducing enteric methane emissions from ruminants, mostly using feed additives. The challenge is to find something that works well over time without harming the animals. Recently a promising additive called 3-nitrooxypropanol (3NOP for short) has been identified and has been submitted to the EU for approval [6]. On average it reduces emissions by around 30% but the effect is very variable, from hardly any to up to 85% reduction [7]. So, not a panacea but definitely progress. Also, this additive is an extra cost and so we would need to incentivise farmers to use it.

It would be nice to know the reasons for the variation in response. Research so far suggests it works better in dairy cattle than beef cattle and this is probably related to the amount of fibre in the diet [6]. It is quite hard to measure methane production from cattle so it is not practical to check this on every farm! (There is a nice article here describing three method including a ‘breathalyser’. Another approach is to fit a sampling harness to the cows nose that they can wear all the time.)

What about offsetting the emissions with carbon storage?

There is huge controversy about how much carbon is stored in the soil when grazing is managed well. Many scientists think that storage only occurs up to a point after which any carbon stored is released by other soil processes and you get a dynamic equilibrium. There is a good discussion of the controversy here from the Food Climate Research Network.

It is of course also possible to offset emissions using growth of woody plants such as trees and hedgerows. The NFU intends to do this too.

My view

I am very glad that UK beef is so much better than the global average. However, it is still very high in emissions compared to pork, chicken and eggs. Also it is terrible compared to plant protein sources such as beans and lentils. I extracted this picture from the BBC food carbon calculator. These figures are probably not specific to the UK.

Chart from the BBC Food Carbon Calculator

It is not practical to reduce the emissions to zero with food additives and manure handling or special grazing regimes. It is possible to offset them with growing trees - but there may be other emissions that are even harder to avoid that we will need those trees for.

I don’t think it is OK to eat lots of beef in the UK because our beef is lower in emissions than the average. Rather, it would be good for our farmers to export it to other countries to displace the worse meat grown in other regions. However, I fear this will not happen unless it is also cheaper.

Which brings us to the worst problem: how do we incentivise farmers to reduce emissions even when it costs extra (such as the food additives) to make this happen? And how do we make sure that systems for this are not abused, for example by using them in conditions when they are not effective?

I would very much like to see a label for UK produced meat that shows that the animal was reared entirely in the UK and all the feed was produced in this country, as well. That would at least ensure no deforestation emissions and could significantly reduce emissions from chicken and pork.

[1] UK farms plan for going 'carbon neutral'(BBC) Sep 2019

[2] Tackling Climate Emissions through livestock (FAO) 2013

[3] Poore and Nemecek (2018) Reducing food’s environmental impacts through producers and consumers. Science.

[4] GHG emissions inventory (NAEI)

[5] Indicator 9: Slurry and manure ( 2019

[6] DSM submits methane inhibitor to EU feed additive approval process Jul 2019

[7] Variation in efficacy of new feed supplement to reduce methane emissions identified Aug 2018

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