Media attention has again highlighted the carbon footprint of eating meat, especially beef, with some journalists concluding that extensive grass-based beef has the highest carbon footprint of all. SFT policy director, Richard Young has been investigating and finds that while the carbon footprint of a year’s consumption of beef and lamb in the UK is high, it is nevertheless responsible for less emissions than SFT chief executive Patrick Holden’s economy class flight to the EAT forum in Stockholm this week.
A recent, very comprehensive, research paper by Poore and Nemecek from Oxford University and Agroscope, a large research company in Switzerland, has again drawn attention to the rising demand for meat, resulting from population growth and increasing affluence in some developing countries. Looked at from a global perspective the figures appear stark. The study claims that livestock production accounts for 83% of global farmland and produces 56-58% of the greenhouse gas emissions from food, but only contributes 37% of our protein intake and 18% of calories. As such, it’s perhaps not so surprising that concerned journalists come up with coverage like the Guardian’s, Avoiding meat and dairy is ‘single biggest way’ to reduce your impact on Earth. This is part of a series of articles, some of which have been balanced, but most of which have largely promoted vegan and vegetarian agendas with little broader consideration of the issues.
The question of what we should eat to reduce our devastating impact on the environment, while also reducing the incidence of the diet-related diseases which threaten to overwhelm the NHS and other healthcare systems, is one of the most important we face. Yet, the debate so far has been extremely limited and largely dominated by those with little if any practical experience of food production or what actually constitutes food system sustainability.
I’ve lost count of the number of food campaigners who’ve told me that all we need to do to make food production sustainable is to stop eating meat. Really? What about the environmental impact of palm oil, soya bean oil, rape oil and even sunflower oil production; the over-enrichment of the environment from nitrogen fertiliser; the decline in pollinating insects; the use of pesticides with known harmful impacts that would have been banned years ago were it not for the fact that intensive crop and vegetable growers can’t produce food without them?
What also about the growing problem of soil degradation, not just in the countries from which we import food, but right here in the UK? Environment Secretary Michael Gove himself has warned that we are 30-40 years away from running out of soil fertility on large parts of our arable land. With only minor exceptions, soil degradation is not a problem on UK grasslands.
Contrary to popular belief, continuous crop production is not sustainable. That’s the mistake made by the Sumerians 5,000 years ago in what is now Iraq, and the Romans in North Africa 2,000 years ago, and in both cases the soils have never recovered. Far from abandoning livestock farming on UK grassland, we actually need to reintroduce grass and grazing animals into arable crop rotations. Despite the drop in demand for red meat in the UK (beef consumption down 4% and lamb consumption down more than 30% since 2000), at least one leading conventional farmer has now publicly recognised the agronomic need for grazed grass breaks. Even before there has been any encouragement in policy, I am aware that some arable farmers are already being forced to re-introduce grass and livestock because they can no longer control arable weeds like blackgrass, sterile brome and couch (twitch), which have become resistant to the in-crop herbicides repeatedly applied to them in all-arable rotations.
Grazing livestock and nature conservation
Seemingly oblivious of these issues, George Monbiot in The best way to save the planet? Drop meat and dairy, on Friday, June 8, also used the research study as evidence to support his claim that if we all gave up meat and dairy we’d be able to re-wild grasslands and live happily by eating more imported soya. Giving up livestock farming would, he believes, allow “many rich ecosystems destroyed by livestock farming to recover, absorbing carbon dioxide from the atmosphere, protecting watersheds and halting the sixth great extinction in its tracks.”
He quoted a passage from the Poore and Nemecek research paper which states that the environmental impacts of converting grass into human-edible protein are “immense under any production method practiced today”. However, ‘immense’ is a subjective adjective. There are many things we do which have far higher negative impacts, most of which are non-essential and do not bring with them the unique benefits that come from grazing animals. Letters responding to the Guardian’s series of articles drew attention to some of these, including issues previously publicised by the Guardian itself.
What about meat and wildlife?
It’s true, and a very great concern, that human activity is destroying the natural world in a completely unsustainable way. The growing of grain crops specifically for intensive livestock is clearly part of the problem, as is highly intensive grassland farming. However, blaming meat consumption so specifically lets an awful lot of practices off the hook. When one considers the rabbits, hares, deer, moles and wild birds killed each year to protect food crops, and the decline in hedgehog and other small mammal numbers since the 1950s – in part due to the removal of hedgerows to make fields larger for crop production – plant-based diets could even be responsible for the deaths of as many mammals and birds as animals slaughtered from the livestock sector.
Since we were (mistakenly in my view) encouraged to switch from animal to vegetable fats 35 years ago, we’ve also consumed and used ever-greater quantities of palm oil from south-east Asia. Its production has been responsible for the near annihilation of many species, including orangutans, pigmy elephants and Sumatran elephants, rhinos and tigers. With demand still growing, similar pressures are now building in equatorial countries in Africa and South America where palm oil production is also taking off. The scientists behind some of the most recent research on species decline blame “human overpopulation and continued population growth, and overconsumption, especially by the rich”, rather than livestock production specifically.
The importance of livestock grazing for wild plants and animals
We also need to remember that many important plant and wildlife species have evolved in tandem with grazing animals and depend on them for their survival, a point made very strongly by Natural England in its report, The Importance of Livestock Grazing for Wildlife Conservation. This is a key reason why the RSPB uses cattle on its reserves, and states that livestock farming is “essential to preserving wildlife and [the] character of iconic landscapes”. And while overgrazing, encouraged by poorly conceived support schemes, has been a problem in the past, the RSPB is concerned that “undergrazing is now occurring in some areas, with adverse impacts on some species, such as golden plover”, while also “contributing to the spread of ranker grasses, rush, scrub and bracken”. Extensively grazed grasslands also have a wide range of additional benefits. They purify drinking water better than any other land use, and they provide food for pollinating insects at times of year when there is little else available. They also store vast amounts of carbon, which if released through conversion to continuous crop production, would accelerate global warming even faster than it is currently occurring.
Food security
Livestock production may only provide 37% of total protein globally, but it clearly provides significantly more than that in the UK. Two-thirds of UK farmland – if we include common land and rough grazing – is under grass, most of that for important environmental reasons. Only 12% of this (8% of total farmland) is classified as arable, meaning that it may, under current EU rules, be ploughed for cropping. Much of this is on farms which grow grass in rotation with crops to build fertility naturally and control weeds, pests and diseases, so when one field of arable grassland is ploughed up another is generally re-sown with grass. If we were to stop grazing cattle and sheep on this land, we would greatly reduce our food security and make ourselves vulnerable, if, for example, extreme weather due to climate change, or a new crop disease were to reduce global soya yields. We would also need to import a very great deal more food, because as I have previously shown, cattle consume only about 5% of the 3.1 million tonnes of soya oil, beans and meal we import (1.1 million tonnes of the 3.1 million tonnes imported is fed to livestock, of which cattle consume only 15%) and sheep consume very little indeed.
The problem with global averages
So far, I’ve rather ducked the key issue of the greenhouse gas emissions from livestock production. Before we can make much progress on this we need first to consider the issue of global average emission figures. Looking at global averages and drawing conclusions from them isn’t actually very helpful. Essentially a small proportion of grazing livestock animals cover a high proportion of the land area and emit a high proportion of the greenhouse gases, while producing only a very small proportion of the meat and milk. The authors of the research paper say, “For many products, impacts are skewed by producers with particularly high impacts…..for beef originating from beef herds, the highest impact 25% of producers represent 65% of the beef herds’ GHG emissions and 61% of land use.”
Simplistically, we might think the obvious answer is to eliminate the 25% of producers who are causing such a large part of the problem. However, this 25% of producers mostly live in dryland regions, such as Sub-Saharan Africa, areas which often have very poor soils and low rainfall. As such their animals grow very slowly, but it is claimed, still produce a lot of methane, because they have to eat very poor-quality herbage. No doubt, people living in the Global South could reduce their carbon footprint from food significantly if they gave up meat and dairy, but they would also very quickly starve.
Approximately a quarter of the global population live in dryland regions where severe droughts are an ever-present threat. Farming families, depending entirely on crops, would have no food at all when the rains fail. In contrast, animals put on flesh in the better years and provide a substantial buffer against starvation, since they can be slaughtered and eaten one by one over significant periods of time in drought years. It also has to be pointed out that unlike many of us in the Global North, who mostly have cars, central heating and fly abroad, the emissions associated with meat consumption in the drylands in the Global South are more or less the only carbon footprint these people have, and amount to just a small fraction of our own.
This aspect also helps us to see how misleading even the headlines on the percentage of land used for livestock production can be, when the very large areas of land in dryland regions are averaged with the grasslands in more fertile regions.
It is also significant that global averages cited by the UN’s Food and Agriculture Organisation in Livestock’s Long Shadow in 2006 (and two other reports in 2013) were dramatically increased by the inclusion of the emissions associated with the destruction of rainforest and virgin land for cattle grazing and soya production, most of which took place before 2005. These were tragic events with multiple causes, but ones which have little relevance to grazing livestock production and beef consumption in the UK, where the predominant land use changes occurring at the time were entirely in the opposite direction – the conversion of grassland to crop production and the planting of trees.
Beef and sheep production in Northern Europe, especially the UK and Ireland, is highly productive and this greatly reduces the carbon footprint of beef and lamb in these regions. These countries have climates and soil types ideally suited to growing grass and only marginally suited to crop production. So using global average figures for the UK also tells us nothing of value.
The scientific debate
I have written to a number of scientists about these issues over the last week, including one of the authors of the research paper, Joseph Poore. Both he and I recognise that there are huge differences in the emissions associated with beef produced in different production systems and that an objective should be to improve systems, wherever possible, to reduce their carbon footprint. While the headlines have focused on the worst examples – beef linked to emissions of between 40 and 210 kg of carbon dioxide (CO2) per kilo – the research study does actually provide data for the second most productive category of beef production which emit 18.2 kg of CO2 per kilo of beef produced.
For anyone not familiar with how these figures are obtained it may help to know that despite being expressed in terms of the greenhouse gas (GHG) CO2, the emissions from beef mostly relate to methane (CH4) and to a lesser extent nitrous oxide (N2O). In order to compare emissions from different sources, these are expressed in terms of CO2 equivalent, based on the relative global warming impacts of the different GHGs, CH4 and N2O, approximately 30 and 300 times higher, respectively, than CO2.
The figures cited in the research paper are global close-to-best, overall average and close-to-worst, but in correspondence, Poore has helpfully given me further information, which shows that beef from the UK dairy herd is typically responsible for emissions in the range 17-27 kg CO2 per kilo. I’ll express this as an average of 22 kg CO2 per kilo of beef to make the calculations later on, less complex. While it is generally assumed that dairy beef has lower emissions than suckler beef, and that could be the case on farms with late maturing cattle, figures for the 100% organic grass-fed beef produced on my own farm suggest that emissions are no higher than 17 kg per kilo of beef, and may even be lower – I can’t do a complete calculation because I don’t have figures for all aspects, for example, the electricity costs at the abattoir where our animals are slaughtered and refrigerated before being brought back to our butchers shop, or the GHG costs of making our hay.
Methane
Despite all this, we cannot pretend that the direct greenhouse gases from grass-fed beef are insignificant. Nevertheless, methane (CH4) breaks down (largely in the atmosphere, and to a lesser extent in soils not receiving ammonium-based nitrogen fertilisers) to CO2 and water after about 10 years. If we contrast grassland with little or no nitrogen fertiliser use with food systems which depend heavily on nitrogen fertiliser, the carbon in the CO2 and the CH4 from grass-fed ruminants is recycled, not fossil, carbon. Ruminants can’t add more to the atmosphere than the plants they eat can photosynthesise from the atmosphere.
The high methane levels in the atmosphere are a very serious problem, but they have become a problem not so much because of cattle and sheep – the numbers of which have increased only modestly over the last 40 years – but because of fossil fuels. Taken together, the fossil fuels, oil, natural gas and coal are not only by far the biggest source of the major GHG CO2, they are also responsible for about a third more methane emissions than ruminants – and all the carbon in that CH4 is, of course, additional carbon that has been stored away deep underground for the last 400 million years. That’s all based on long-established data. But a more recent study analysing the relative amounts of the isotopes carbon12 and carbon14, which vary according to the source of the methane, has found that scientists have previously under-estimated methane emissions from fossil fuels by 20-60% and over-estimated those from microbial sources, such as the rumen bacteria which produce methane, by 25%. That doesn’t affect the figures in Poore and Nemecek’s paper, but it does help us to see more clearly the relative importance of reducing fossil fuel use compared with red meat consumption. In that respect, re-localising food systems, discouraging supermarkets from centralising their distribution networks, consuming the foods most readily produced in the UK and minimising imports would surely be a good start?
Soil carbon sequestration
Unlike some leading campaigners and scientists who call for big reductions in ruminant numbers and largely dismiss the significance of soil carbon sequestration, Poore and Nemecek accept that carbon sequestration under grassland can, under certain circumstances, for a finite period, offset a significant proportion of the emissions from cattle and sheep. According to them the maximum extent of this is a reduction of just over one-fifth (22%) of the emissions. However, since they cite no UK-specific data in their study it is not clear whether this has any relevance to the UK or whether it is simply a global average.
About half of soil organic matter is made up of carbon. The rest is mostly nitrogen and water. Organic matter is critically important to long term soil resilience and water-holding ability. The general assumption amongst scientists is that organic matter levels fall, year on year when grassland is converted to cropland, and eventually stabilise at a new lower level on clay-based soils after a century or more. Peat-based and sandy soils are an exception since under continuous cropping they will continue to lose organic matter until there is none left, witness the Fens in East Anglia and many of the world’s deserts, which were once fertile farmland. In contrast, the conversion of croplands to grass will rebuild that carbon over broadly the same period. Overstocked land will also lose carbon. Ley/arable rotations will see levels go up and down depending on the phase of the rotation and the proportion of arable to grass crops.
As such, many long-established, well-managed soils under permanent grassland in the UK are probably already close to their maximum potential level of carbon. In contrast, heavily stocked grasslands do have potential to sequester more carbon if their management is improved, while all croplands could steadily regain carbon if they were converted to grass or to rotations including grass breaks. Since a third of soils globally are significantly degraded and another 20% moderately degraded the global potential for carbon sequestration is considerable.
Confusion has arisen due to the very significant variation between the rates of sequestration found in many studies. However, a review of 42 studies in 2014 found that more than half these differences could be explained by considering whether or not livestock manures were returned to the land. It seems likely, based on other research, that much of the remaining differences will relate to land management, stocking levels and precipitation levels. Deeper rooting grasses, legumes and herbs also have the potential to increase carbon down to much greater depths than the most widely used ryegrasses which are shallow-rooting.
Undertaking a calculation
Can we find a way of relating the emissions associated with beef to other things we do to get some idea of their relative significance? I’ll use the average 22 kg of CO2 for beef from the UK dairy herd (established above) as it’s the only solid figure I have for the UK. In 2015 and 2016, according the AHDB’s UK yearbook – cattle, average beef consumption per person in the UK was 18.2 kg and average consumption of lamb was 4.9 kg. So we can now undertake a calculation to establish the carbon footprint of a typical beef and lamb consumer.
- Beef 18.2 x 22 = 400.4 kg carbon dioxide equivalent
- Lamb 4.9 x 25 = 122 kg carbon dioxide equivalent (based on figures in the study)
On this basis an average British beef and lamb consumer is responsible for the equivalent of 522 kg of CO2, as a result of their red meat consumption. This doesn’t of course include the emissions associated with chicken and pork, but to get some idea of whether giving up red meat is the single most important thing you can do to save the planet, I used an online calculator to work out how much CO2 was emitted as a result of SFT chief executive Patrick Holden’s return flight from Heathrow to Stockholm for the 2018 EAT forum this week. That comes to 466 kg of CO2. Undertaking a similar exercise for the round trip journey by car from his farm in Wales to Heathrow adds another 110 kg, making a total of 576 kg carbon dioxide, for one trip to a nearby country, compared with 522 kg for a whole year’s worth of red meat eating.
One question which therefore arises from this is whether the repeated focus on red meat as a source of global warming is misleading the entire population into assuming that providing they don’t eat red meat they can travel abroad as much as they like with a clear conscience? It’s of note that a roundtrip from Heathrow to San Francisco is equivalent to about five years’ worth of beef and lamb produced in the UK – and quite a few of the vegetarian and vegan campaigners at the EAT forum had come from the US.
Why we need grazing livestock
More than all these issues, however, the SFT defends the role of grazing animals, as we know from years of practical farming experience that systems with cattle or sheep at their core are able to remain highly productive, repair degraded soils and avoid the GHG emissions associated with the manufacture of nitrogen fertiliser, equivalent to about 8 tonnes of CO2 for every tonne of nitrogen used. Farmers growing bread-making wheat and oilseed rape in the UK use up to 250 kg of nitrogen per hectare, meaning that each hectare puts GHGs equivalent to 2 tonnes of CO2 into the atmosphere, just in relation to nitrogen. About half of this nitrogen is lost to the environment and has a wide range of negative impacts on soils, water, the air and on our health. This diffuse pollution has major negative costs for society, estimated by scientists to be 2-3 times higher than the commercial benefits farmers get from using nitrogen fertiliser.
In contrast, using forage legumes, like clover, instead, allows nitrogen to be built up in the soil under grazing swards without any GHG emissions. This can then be exploited to grow crops in subsequent years, before going back to grass and clover. Such grassland systems are almost as productive as those using the highest rates of nitrogen fertiliser. Grain yields are lower, but if we move away from grain-fed livestock that won’t matter. Grain legumes like beans and peas do also fix some nitrogen naturally, but it is not enough to make a significant contribution to reducing nitrogen use in subsequent crops. In addition, not all cropland in the UK is suitable for growing peas, and it’s not possible to grow beans more than one year in five, even with repeated applications of herbicides, fungicides and insecticides.
In conclusion
Clearly there are significant emissions associated with meat production, and it may well be that, in general, grass-fed beef has slightly higher direct emissions than grain-fed beef. I can see big advantages, both environmental and ethical in reducing the production and consumption of grain-fed meat, be it chicken, pork or beef. But there is an overwhelmingly important case why we should continue to produce and eat meat from animals predominantly reared on grass, especially when it is species-rich and not fertilised with nitrogen out of a bag.
Yet, while a few farmers are trying their best to counter the prevailing trends by producing organic or grass-fed meat, far more cattle are now being housed in American-style feedlots, as recently exposed by the Guardian. Ironically this trend is occurring largely due to the failure of scientists, journalists and campaigners to understand the full significance of the differences between farming systems, and therefore the red meat which brings major benefits as well as a few negative impacts, compared with that which only has negative impacts. Due to falling demand for red meat, smaller, more traditional farmers are being forced to choose between giving up – something which has now affected tens of thousands of them – and intensifying, in order to cut costs and stay in business. I very much hope we can find a way to broaden understanding of these issues, because if we can’t, we will see the further spread of most intensive beef systems and we will lose the iconic pastoral character of the British countryside.
This article received light editing on 25 June 2018 and the inclusion of the section on soil carbon sequestration, in response to comments received. A copy of the article as originally published is available on request from megan@sustainablefoodtrust.org
