Category Archives: Greenhouse Gas Emissions

Oxford Student Union’s beef and lamb ban is laughable when compared to the Uni’s air travel emissions.

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There has been considerable publicity devoted to the announcement that the University of Oxford Student Union Council have voted to approve an on-campus beef and lamb ban, citing a desire to reduce greenhouse gas emissions.

The greenhouse gas emissions associated with beef production comprise methane, nitrous oxide and carbon dioxide, with methane accounting for ~60-80% of the total, depending on the production system. Ironically, climate researchers at the University of Oxford (who presumably don’t sit on the Student Union Council) have reported that atmospheric methane breaks down over ~20 years, unlike carbon dioxide from fossil fuel combustion (e.g. aviation fuel) which continues to accumulate over time.

I grew up in Oxford and have always loved the diversity added to the city residents by the truly global university community of students, researchers and staff.  However, it’s worth thinking about the carbon emissions of all the international flights that are therefore associated with the university (see infographic above).

To put flights into context:

  • The carbon emissions associated with a return flight to Paris = 4.8 months of beef consumption* per passenger.
  • The carbon emissions associated with a return flight to JFK = 2.8 years of beef consumption* per passenger.
  • The carbon emissions associated with a return flight to Sydney = 9.5 years of beef consumption* per passenger.

We should all take strides to reduce our greenhouse gas emissions wherever possible – surely we can only assume that banning air travel will be next on the Student Union Council agenda?

It’s worth noting that this vote doesn’t actually have any legislative power, as each college within the University runs its own catering and therefore makes independent decisions as to food sourcing. Furthermore, a vote by the Student Council is a vote by a very small proportion of students on the council, rather than the 22,000 students across the entire University. It therefore seems unlikely that the ban would be mandated without significant student revolt, but given how many kebab and burger vans line the streets of Oxford after 9pm, I imagine the proprietors are looking forwards to a huge increase in demand if it is ever enforced.

*at an average UK consumption of 18.2 kg beef per capita 

Cattle, Cowgirl Boots And Cancer

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581677_10153042743360587_388837289_nLast week I was lucky enough to chat with the fabulous Will Evans, a Welsh cattle and hen farmer on his Rock and Roll Farming podcast.

Unlike most of my media interviews, which are focus entirely on sustainability and have me spouting numbers like data is going out of fashion; this was a huge amount of fun and Will got me admitting to a celebrity crush, the fact that I have to put bacon and cheese on hot cross buns and the fact that, as an undergrad, I was so useless at presentations that even the lecturers felt sorry for me.

So if you fancy listening to a fabulous Welsh accent (Will) and a slightly overexcited Oxford/Shropshire/Montana-hybrid (me) discussing the best types of cheese, beating cancer at 25 and the perils of being a reformed vegan in addition to the best way to ensure future livestock sustainability (hint: there’s no one-size-fits-all), check it out here.

Jamie Oliver Should Be Presenting Friday Night Farming Facts – Not Feasting On Foodie Fiction

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Commercial dairy cows in Cumbria – should they be “retired” before slaughter?

Good grief. Just when I think I’ve heard it all, another food pundit comes up with an idea so daft that you could bottle it and sell it as vegan, gluten-free, dairy-free, humanely-reared organic water. The latest brainwave from Jamie Oliver is to “retire” old dairy cows onto pasture, where they can graze for four years before producing highly-marbled beef. Contrary to most of the breed-related marketing, Holstein beef is pretty good, so it’s a mouth-watering concept until we take a step back and think about the actual sustainability impacts.

Producing beef from cull dairy cattle? Excellent idea. I once had a heated argument with an activist protestor outside the Smithsonian Museum in Washington DC who seemed surprised that, when he told me that most cull dairy cows end up as burgers, I didn’t renounce my heathen ways and immediately seek out the nearest tofu burrito. It makes perfect sense – where would be the logic in discarding an entire cow’s worth (~301 kg) of nutritious, delicious beef simply to bury, burn or use the meat for non-food purposes? Indeed, ~50% of the UK (and ~24% of the US) beef supply comes either from cull dairy cows or dairy calves reared for beef.

Is there an argument for giving extra feed to cows that are going to be culled so that they get a little fatter and produce tastier beef? Yes indeed, adding value to cull dairy cows is a great idea, especially when the beef price is high. But here’s the rub. The average dairy cow in the U.K. is culled at 6.4 years of age. By that time she should have reached her mature weight, which means that the majority of extra weight she puts on in “retirement” is fat. Although we love the streaks of intramuscular fat that we see in a steak (marbling) and enjoy the depth of flavour that gives to the meat, the vast majority of fat on a carcass isn’t particularly edible. So we’re feeding a cow for four years of retirement in order to discard (or rather render into tallow – perhaps to make some £5 notes?) a significant proportion of the weight that she gains.

A cow will eat 2-2.5% of her body weight in dry matter every single day. Four years of feeding a 700 kg cow = 4 x 365 days x 700 kg x 0.025 = 25,550 kg of feed dry matter, or 106,458 kg of fresh grass given that it’s only ~24% dry matter. Plus 4-years worth of drinking water, manure and greenhouse gas (GHG) emissions. A hefty environmental impact compared, for example, to rearing two beef steers on the same amount of pasture over a 4-year period, in addition to culling the dairy cow when she leaves the herd (sans retirement). That scenario would provide 200% more beef (~900 kg total, even allowing for the lighter weight for grass-finished vs. grain-fed steers) from the same amount of pasture and with a smaller total quantity of manure and GHG emissions because the growing animals are lighter in weight throughout, therefore excrete and emit less*.

I can’t decide whether the increasingly asinine proposals for sustainable food production propounded by Jamie Oliver’s “Friday Night Feast” programme, which recently left the casual viewer with the impression that welfare of housed dairy cows is equivalent to that of battery hens are serious, or simply a way to court fame through controversy. However, the number of tweets lauding the programme’s food philosophy is alarming given the amount of time devoted to non-sustainable ideology. Time for TV programmers to redress the balance with some Friday Night Facts vs. Fiction?

*Note that I have not accounted for the beef cows needed to produce the steers, nor for the cost of rearing the dairy cow or the heifer needed to replace her in dairy herd. This is not a full system assessment, but simply about the best use of a unit of pasture area – adding fat to a mature cow (less efficient) or adding muscle and fat to growing animals (more efficient)

Low Meat, Faux Meat or No Meat – Should Retailers Really Reward Us for Buying Vegetarian Foods?

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All food have an environmental impact

There’s no doubt that eating more fruit and vegetables is a positive idea. Nationally we still don’t hit our 5-per-day and lifestyle diseases are major causes of premature death. However, as Sainsbury’s redesigns aisles to try and convince shoppers to swap meat for vegetables and plans to issue extra loyalty points to customers choosing vegetarian foods, are we in danger of applying myopic solutions to a seriously complex issue?

Most people in developed countries eat more than the recommended 70 g of meat per day. If (and this is debatable) the researchers who claim that meat consumption is linked to lifestyle disease are correct, then reducing the amount that we eat may be a positive step. However, much of the justification for cutting meat consumption appears to be on the basis of reducing environmental impacts.

So how do we ensure that we eat a diet with a low carbon footprint? It’s very simple. Drewnowski et al. (2015) showed that grains, syrups and sugars had the lowest carbon emissions per kg of food – considerably lower than meat and dairy products. So we simply reduce the proportion of meat and increase the quantity of sugar that we eat each day. Just replace meat products with Mars bars and golden syrup and we’ll save the planet, albeit in conjunction with a spike in type II diabetes and a significant protein deficit.

If Sainsbury’s is determined to reward consumers for making healthier choices, why not do so based on the proportion of fruit, vegetables, lean protein and dairy purchased vs. cakes, biscuits and crisps; rather than giving extra loyalty points for vegetarian products? After all, a snickers bar or a packet of oven chips are both vegetarian, but meat-free foods are not inherently healthy choices. Furthermore, where do fish and dairy fit into the new regime? Given the low nutritional value of soy and oat juices per unit of greenhouse gas emissions compared to dairy, the potential for child malnourishment is considerable if plant-based foods are mis-sold as being nutritionally-equivalent to animal products.

Bipolar “A is bad, B is good” panaceas do nothing to improve consumer knowledge of food production or environmental impacts. Strawberries may have a lower carbon footprint than beef, but cannot be grown on a rocky slope in Scotland. Pork may have a relatively high water footprint, but almonds use even more. Lettuce is a great source of fibre, but provides very little additional nutrients per kg compared to meat. In my experience as an ex-vegan, the majority of vegan restaurant dishes are largely reliant on pasta or rice to bulk out the vegetables. Is this really a healthier choice than lean meat and vegetables? Given that many young people have little or no interest in cooking, is the presence of spiralised courgettes or cauliflower rice at the end of the aisle going to engender a sudden interest in all things gastronomic?

Most people’s diets are led (to a greater or lesser extent) by the foods available in the local supermarket, therefore retailers have huge opportunities to educate, encourage and improve our food choices. It’s not clear why Sainsbury’s would choose to launch this initiative, but it appears to be a box-ticking exercise, designed to address a single minor issue while ignoring the bigger problem.

The Future’s Bright; The Future’s…Meaty? A Response to Breakthrough’s Essay on Meat Production

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jims-charolais-in-feedyardThis week I was asked to respond to an excellent Breakthrough article on the environmental impacts of beef production. As ever, I hope the comments below provide food for thought (pardon the pun) and I urge you to read the full Breakthrough article as well as the other comments by Jayson Lusk, Maureen Ogle and Alison van Eenennaam.

Every food has an environmental impact, whether it’s cheeseburgers or tofu, coffee or corn.

That shouldn’t come as a surprise to any of us and, as a scientist, sustainability consultant and parent, I don’t have a problem with food production being one of the biggest contributors to global environmental impacts. Why? Because food production is one of the few industries that are absolutely essential for human life. However, it’s clear that we need to take steps to reduce environmental impacts from human activity, and as such, the livestock industry is often criticised for both resource use and greenhouse gas (GHG) emissions.

Although meat production is predicted to increase from now until at least 2050, it should be noted that the trends for improved productivity and efficiency within global livestock industries also reduce environmental impacts. As described in Marian Swain’s essay on meat production, the US beef industry cut resource use and greenhouse emissions considerably between 1977 and 2007. Meanwhile, the rise of modern feedlot-finishing systems cuts land use, water use, and emissions per unit of beef compared to grass-finished meat.

These findings may seem intuitively incorrect as we’re constantly exposed to marketing and media messages suggesting that only grass-fed meats are environmentally sustainable, and that intensive livestock systems are undesirable. The data speak for themselves however—the majority of extensive systems finish cattle at lighter weights (thus requiring more total animals to maintain beef supply), have lower growth rates (so cattle take longer to grow to their finish weight) and often have lower reproductive performance in female cattle.

All these factors combine to increase environmental impacts. But when I presented this data to a group of French Masters-level Livestock Engineering students earlier this month, they were (in their own words) shocked. Even among experts and students, there remains a great deal of misunderstandings when it comes to meat production.

Does this mean that every beef producer worldwide should embrace feedlot-finishing and reduce pasture use? Absolutely not. One of the major benefits of cattle compared to swine and poultry is that they digest and use human-inedible forages, such that dairy and grass-fed beef cattle actually produce more human-edible protein in the form of milk and meat than they consume; and feedlot-finished beef cattle have a ratio of human-edible feed intake to human-edible protein output similar to that of swine, despite their greater overall land use. In keeping with the themes discussed in the Swain’s essay, there is no magic bullet—it is essential to fit production systems to the cattle, climate, market, and culture within each region and to improve productivity within each and every system.

So rather than reducing animal protein consumption as we move towards 2050, we might ponder keeping total consumption relatively stable, with a more equitable distribution across the globe? This would allow for a decrease in over-consumption in high-income regions, while providing a greater quantity of milk, meat, and eggs to those who have dire need for adequate animal proteins to maintain health and to promote adequate child growth and development. While the environmental impact of beef production is a key concern, we also have to examine the role of livestock in economic and social sustainability.  For billions of small-scale farmers, cattle provideeconomic viability, improved nutrition, social status and a means to diversify agricultural production as well as tangible benefits in terms of fertilizer, hides and other by-products.

Should we insist that global beef production is abandoned in favour of increased legumes, nuts or lab-created proteins? No. We simply need to give producers worldwide the education, tools and technologies to make the best and most efficient use of their resources. Only then will we have a truly sustainable (environmentally responsible, economically viable and socially acceptable) global meat industry.

Does Size Matter? Dairy Efficiency Becoming Paramount During Crisis

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Media articles relating to agriculture appear to fall into two groups. Those relating to small-scale agriculture are glowing accounts of farmers wearing overalls and straw hats; lovingly taking care of the land and animals according to holistic principles; and selling their produce at the local farmers’ market. By contrast, commentary upon large-scale agriculture invokes images of corporate-controlled factory farms with blatant disregard for animal welfare and local community issues; blithely pumping animal manure into water courses.

To consumers, the majority of whom do not understand agriculture, but have questions about how their food is produced, the choice (as presented by the media) is clear. Small farms must be better for the environment, the economy and the local community. According to the Food and Agriculture Organisation of the United Nations (FAO), we need to sustainably intensify food production over the coming years in order to feed the increasing global population. For many however, the concept of intensification and high-efficiency production systems appears to be contrary to the holistic, small-farm philosophy.

Small cows dominateI will be presenting at the “World Congress on Controversies and Consensus in Bovine Health, Industry & Economics” in Berlin later this week, and have been asked to debate the question “Are hyper-intensive, mega farms more efficient?” If we examine the science, the results are unequivocal.

To use the U.S. dairy industry as an example: over three-quarters (76.7%) of dairy farms have small herds (less than 100 cows) and only 4.2% are large, with more than 500 cows in the herd. Yet the contribution to total milk supply is disproportionate – those 76.7% of herds containing <100 cows produce only 13.7% of U.S. milk, whereas the 4.2% of farms with >500 cows produce 63.0% of U.S. milk. A 17% Large cows dominateincrease in milk yield per cow is exhibited in large herds compared to small herds – does this mean that so-called mega farms are more efficient? Yes. They have a higher output of milk per unit of input. Data from the FAO also shows that as milk yield increases, the carbon footprint (and other resource use impacts) per unit of dairy is reduced.

Yield per cow and herd size (metric)Does this mean that large herds are better? Not necessarily. There’s no measure of animal health, worker conditions, or community support in these data. Yet these issues are size-independent. It’s possible to have poor animal health or worker conditions on a small farm, just as it is on a large farm. I’ve seen some great small operations, but also visited amazing large farms, including a 1,200 cow dairy in SE England where I was extremely impressed to see that they had a hospital pen to segregate sick cows from the rest of the herd, and that it only contained 12 cows. A 1% morbidity rate. How would that compare to the average human workplace, school or city?

Size isn't importantIs there an ideal farm or herd size? A blueprint to lead the global dairy industry during the current crisis? No. Dairy farms vary considerably – it would be foolish to suggest that there is only one sustainable way to produce milk (although this approach is often taken by certain NGO groups). However, one thing is clear. As we approach a global population of 9.5+ billion people in 2015, we need to stop vilifying large farms and worshipping small farms, and instead promote efficient, well-managed, productive farms that can survive the crisis, regardless of size. As the saying goes – it’s not size that matters, it’s what you do with it that counts.

Defending Conventional Beef in The Wall St Journal Today!

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WSJShameless self-promotion, but very excited to have an essay published in The Wall St Journal today defending conventional beef production.

Given my blog subtitle, I thought I should link to it! Would love to read your comments. Article here: http://www.wsj.com/articles/is-feedlot-beef-bad-for-the-environment-1436757037

Planes, Trains and Automobiles: Why Mass Food Transport is Eco-Friendly

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Food transportation. It’s the curse of the modern world. Just think how much brighter and sunnier the planet would be if we all shopped locally, tootling along on our bicycles to pick up freshly-baked bread and a dozen eggs just as our grandparents would have done. A brave new world unemcumbered by gas pumps and trucks. Except…. Well, no. It’s not that simple.

Food miles 2 In many cases, transport is a tiny proportion of total greenhouse gas emissions per unit of food – for example, it’s less than 1% of the carbon footprint of one lb of beef. However, food miles are often cited as an environmental proxy to differentiate between food choices, the assumption being that an egg which travels 2,000 miles across the country is less environmentally-friendly than one produced in the next county. Indeed, one farm website proclaims that “We do not ship anything anywhere. We encourage folks to find their local producers and patronise them”, while on the same page, a customer testimonial proudly proclaims: “I drive to <Farm X> 150 miles one-way in order to buy clean meat for my family”.
Food miles 4Given the dichotomy between these two statements, let’s compare buying eggs from a grocery store with a local farm (full analysis here). Food miles are far greater for eggs that have traveled from Texas to Virginia to be sold in the grocery store (2,405 miles round-trip), compared to driving to the local farm (300 miles round-trip); and the fuel efficiency is far worse for a truck (5.4 mpg) than a car (22.6 mpg); yet a modern truck can carry 23,400 dozen eggs.
Food miles 6Unless your car is packed to the roof with eggs, traveling to the farm to buy them emits 55X more greenhouse gas emissions than driving to the store to buy them. Bottom line? Unless the local farm is closer than the store, or you’re able to walk/cycle there*, it’s more environmentally-friendly to buy eggs from the store, because the greenhouse gas emissions attributable to one dozen eggs out of 23,400 dozen is a tiny fraction of the total.
One report claims that greenhouse gas emissions from one large container ship is equivalent to 50 million cars – however, in this instance it’s the result of sulphur dioxide emissions from poor quality shipping fuel rather than inefficiency. Mass transport may not have a feel-good factor associated with driving out to a farm, but it allows us to enjoy a wide variety of affordable foods with a low carbon footprint – essential factors for a sustainable food future.
*Which begs the question of how many eggs you can carry on a bicycle…