Long Read - May 2019

Food in the Anthropocene

A growing body of research is making clear the fact that the way we eat is unsustainable, for human health and for the environment. With our food system responsible for at least 15% of greenhouse gas emissions, and an increasing burden of ill health related to consumption of red and processed meat, there is an urgent need to find answers to the question of how to feed the world’s population - projected to reach 10 billion by 2050 - in a healthy and sustainable way.

When it comes to the links between our diets, our health and the environment, the research picture is wide-ranging and complex. It encompasses not just agriculture, climate science and nutrition but also questions around food choices, societal norms, aspirations and identities.

How we transport our food, store it, cook it, and how much is lost or wasted (an estimated 30% worldwide) are also key considerations in the sustainability of our food system as a whole. And widely varying scenarios across the globe mean there can be no one-size-fits-all solution – while in affluent societies excessive calorie intake has contributed to a rapid rise in rates of obesity, in the developing world more than three billion people are classed as malnourished.

The work of the Oxford Martin School’s research community seeks to inform multiple facets of this issue, contributing to both the scientific evidence base and the public discourse around healthy, sustainable diets. From fundamental changes to farming methods to the potential of alternative protein sources, our work in this area is focused on identifying solutions that will benefit both people and planet.

Meat: a key contributor to global warming

The world’s total global meat consumption currently stands at more than 300 million metric tonnes per year, having risen from seven million in 1960, and could rise by as much as 76% by the middle of this century (including a doubling in the consumption of poultry, a 69% increase in beef, and a 42% increase in pork). The rearing of livestock for meat, eggs and dairy products generates some 15% of total global greenhouse gas emissions and uses 70% of agricultural land.

A 2014 paper published in Climatic Change was the first to provide quantitative evidence that going meat-free can dramatically reduce the impact of our diets on the environment. The researchers analysed data from the diets of 65,000 meat eaters, fish eaters, vegetarians and vegans who had taken part in an Oxford-based cancer epidemiology study, and found the greenhouse gas emissions associated with a meat-based diet were approximately twice as high as those for vegans, and about 50 per cent higher than for vegetarians. As an example, if someone eating more than 100 grams of meat a day simply cut down to less than 50 grams a day, their food-related emissions would fall by a third.

On the thorny question of whether we need to stop eating meat to save the planet, study co-author Dr Peter Scarborough said people did not necessarily need to give up meat completely: just cutting down makes a big difference.

The environmental cost of 'business as usual’

Without concerted action, the environmental impacts of the food system could increase by 50-90% by 2050 as a result of population growth and the rise of diets high in fats, sugars and meat, according to an October 2018 study published in Nature.

Those impacts could lead to proposed ‘planetary boundaries’, relating to changes in land use (e.g. from forest to grazing land), freshwater use and over-application of fertilisers, among others, being surpassed, leading to instability in the natural systems upon which life depends.

Adopting more plant-based, ‘flexitarian’ diets globally could reduce the greenhouse gas emissions of the food system by more than half, the authors found. Indeed, they argued that we will fail to sufficiently mitigate climate change if we don’t change the way we eat. But the study made clear that no single solution will be enough to solve the problem: we must also improve management practices and technologies in agriculture, and halve the amount of food we waste or which is spoiled before it reaches consumers.

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The world’s total global meat consumption currently stands at more than 300 million metric tonnes per year

Can grass-fed cattle help cut carbon?

Some commentators have argued that well-managed grazing can remove carbon dioxide from the atmosphere and sequester it in soils, and that these removals can substantially compensate for, or even exceed, all other emissions from the livestock that are doing the grazing. So could grass-fed beef be a climate solution, rather than a problem?

Professor Tara Garnett’s 2017 report, Grazed and Confused?, provided in-depth analysis of the issue, concluding that grass-fed cattle remain net contributors to warming. She commented: “Ultimately, if high consuming individuals and countries want to do something positive for the climate, maintaining their current consumption levels but simply switching to grass-fed beef is not a solution. Eating less meat, of all types, is.”

Bringing about change: options for policy makers

An extensive review published in Science in August 2018, led by the Oxford Martin School’s Director, Professor Charles Godfray, looked at the options for policy-makers to effect change in people’s eating habits. These ranged from ‘rational choice’, consumer-led options such as changes to nutritional labelling, through to fiscal interventions such as taxes. The latter idea provoked considerable public debate at the end of 2018 with the publication of a study modelling the potential benefits of a tax on red and processed meat. The research, led by Dr Marco Springmann, calculated that optimal taxation to account for health costs in high-income countries would mean a 20% tax on red meat and more than 100% on processed meat like bacon, sausages and jerky. Such measures could prevent 220,000 deaths globally and save over US$40 billion in healthcare costs every year, he found.

A healthy, sustainable diet: the lowdown

Oxford Martin School research played a key role in the formulation of the ‘planetary health diet’ outlined in the widely-reported EAT-Lancet Commission report, published in January 2019, which looked at how the world’s population can be fed within environmental limits. The report advocates a ‘flexitarian’ diet: largely plant-based with unsaturated rather than saturated fats, and optional modest amounts of fish, meat, dairy and added sugars.

The authors recommended that by 2050 global consumption of foods such as red meat and sugar will need to decrease by more than 50%, while consumption of nuts, fruits, vegetables, and legumes must increase more than two-fold. The report emphasises that key to enabling this shift is ensuring that healthy diets are accessible and affordable to all, with social protections to ensure low-income groups are not adversely affected by any rises in food prices.

Alternative proteins to the rescue?

A dramatic difference in carbon emissions

A study by the Oxford Martin School’s Director, Professor Charles Godfray, for the World Economic Forum set out the health and environmental benefits of changing the protein sources in our diets from meat to alternatives such as mycoprotein, algae, peas, insects and lab-grown meat. It showed that these protein sources could reduce the overall global burden of diet-related deaths by 2.4%, with that number climbing to 5% in high- and upper-middle-income countries, and laid bare the striking difference in CO2 equivalent emissions between beef (23.9kg emissions per 200kcal) and alternative protein sources such as beans, insects, wheat and nuts (1kg per 200kcal). Chicken and other protein sources such as tofu, pork and alga produce only 3-6 kilograms CO2 equivalent.

Professor Godfray said a dialogue would be needed for a successful, large-scale transition to sustainable protein sources, saying: "For the foreseeable future, the meat and alternative‑protein industries will coexist and have the opportunity to complement one another. Both incumbents and new players, and the various stakeholders who are involved throughout the protein supply chains, will gain from a nuanced debate about how to evolve and reshape regional and ultimately global food systems to provide healthy and sustainable diets.

"Only through dialogue and structured collaboration will society be able to transform the protein system, to create a future where safe, sustainable, affordable and healthy protein is provided to all."

New proteins, old narratives?

With innovative alternative protein products beginning to make their way onto supermarket shelves and restaurant menus, considerable hype and discussion has built up, creating a new narrative landscape that will feed into consumer choices. Lab-grown meat has yet to reach commercial production but has already been extensively marketed and written about in the media.

Recent work by Dr Alexandra Sexton, researcher with the Oxford Martin Programme on the Future of Food and the LEAP programme, has examined the narratives (and counter-narratives) being created around new protein sources, from plant- and insect-based products to lab-grown meat. Analysing the promises contained within a range of marketing materials, she found cultural representations around gender and meat-eating were often being reinforced, and also noted embedded neo-colonial tendencies, such as promising to feed the world, often with an emphasis on ‘technofixes’ as a means for doing so.

Lab-grown meat: not yet a climate cure

One of the heralded promises of lab-grown meat is its potential for radically reducing the greenhouse gas emissions involved in meat production. Research from the LEAP programme was the first to assess the climate-change impact of several production methods for lab-grown and farmed beef, accounting for the differing greenhouse gases produced.

John Lynch and Raymond Pierrehumbert found that some projections for the uptake of particular forms of cultured meat could indeed be better for the climate, but others could actually lead to higher global temperatures in the long run. With current uncertainties around how cultured meat would be produced at scale, they concluded that the availability of low-carbon energy sources to fuel production will be key if lab-grown meat is to help in the drive to reduce carbon emissions.

Farming for the future

Changing what we eat can help to dramatically reduce carbon emissions but, as highlighted earlier in this article, it is only one part of the picture. We are facing a pressing need to produce more, nutritious food for the world’s growing population - one way to do this is through fundamentally redesigning our agricultural systems to increase yields while reducing environmental impacts such as pesticide pollution, soil erosion, and greenhouse gas emissions, an approach known as sustainable intensification.

A 2013 paper by Dr Tara Garnett and colleagues in Science examined the premises of sustainable intensification, situating the approach within a broader framework of priority actions for the food system, such as environmental considerations and systems of governance that improve the efficiency and resilience of the food system.

They wrote, "As we envisage it, sustainable intensification demands radical rethinking of food production to achieve major reductions in environmental impact. In some areas, increases in yield will be compatible with environmental improvements. In others, yield reductions or land reallocation will be needed to ensure sustainability and deliver benefits such as wildlife conservation, carbon storage, flood protection, and recreation. An overall increase in production does not mean yields should increase everywhere or at any cost: The challenge is context- and location-specific."

Discussing the research, Professor Godfray said: “The challenge of achieving sustainable food security for all is only in part a supply-side problem. Producing more food is important but it is only one of a number of policies that we must pursue together.”

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