The new IPCC publication, Mitigating Climate Change, released on 4 April 2022, includes for the first time in the panel’s 34-year history the impacts of the food system in the global calculus of environmental impacts. In the section dealing with agriculture, forestry, other land uses and food systems, the report – which had 278 authors from 65 countries, and runs to 2,913 pages – explores the human consumption of various energy sources and foods, and their resulting greenhouse gas (GHG) emissions. 

The just-released “mitigation” report makes clear that our consumption choices – and how consumer demand translates into what energy and food producers offer us – are going to play a critical role in all efforts to turn the tide on climate change: Having the right policies, infrastructure and technology to support the necessary changes to our lifestyles and behaviour – including what we eat – could result in a 40-70% reduction in greenhouse gas emissions by 2050, the report says.

How what we eat affects climate change 

We are not used to thinking about the climate crisis as being directly linked to what we eat – but they are two sides of the same coin. What we choose to eat (and grow) has an impact on the climate, and the rapidly changing climate has an impact on what we can grow, and where.

“Food is the single strongest lever to optimise human health and environmental sustainability on Earth,” said an earlier report from the EAT-Lancet Commission in 2019, which laid out a “planetary health diet” – an ideal healthy diet for humans from sustainable food systems.

Our current globalised, industrialised food system already poses huge environmental problems: Different estimates place food production as responsible for between one quarter (26%) and more than a third (42%) of all GHG emissions, 70% of freshwater use, and 40% of land coverage. (The IPCC gives a range of 23-42% for food production’s overall share of GHG emissions, while acknowledging that there is still widespread hunger and malnutrition.)

Beef has the biggest carbon footprint, anywhere, of all the foods we eat, at about 15kg of GHG emissions per serving, while just about everything else emits less than half of that per serving, said the journal Science, in 2018. 

Beef has by far the biggest carbon footprint of all foods, at around 15kg of greenhouse-gas (GHG) emissions, including methane, per serving. This is more than double the emissions caused by production of lamb, fish, pork or chicken. The highest-impact vegetable proteins emit less GHGs than the lowest-impact animal protein. (Chocolate from non-sustainable sources ranks close to ‘low-impact’ beef in GHGs.)
(Source: Science magazine)

Of the conservative estimate of 26% of GHG emissions caused by food production:

• 31% is attributed to livestock and fisheries (animals raised for meat, dairy, eggs, and seafood production): This comes from “on-farm” production emissions, including the methane produced by ruminant livestock (mainly cattle) through their digestive processes. 
• 27% is attributed to crop production: This breaks down to 21% from crops produced for human consumption, and 6% from the production of crops for animal feed. This category includes all the emissions caused from the processes of agricultural production, including methane from rice production, nitrous oxide from fertilisers and manure, and carbon dioxide from machines used for agriculture.
• 24% is attributed to food-related emissions from land use, which includes 16% from land used to keep livestock, double the emissions compared to those from crops grown for human consumption (8%). This category includes the conversion of forests (think Amazon rainforest deforestation to raise cattle and more deforestation to grow the soy to feed them), grasslands and other land that previously acted as a “carbon sink” – a sponge for absorbing and neutralising carbon – but once turned into pasture or cropland, becomes a net carbon-dioxide emitter.
• 18% is from supply chains, which covers everything involved in the processing, transport, packaging and selling of food, all of which need energy and other resource inputs. Transport accounts for one third of this (6%).

Greenhouse-gas (GHG) emissions from food production make up at least one quarter (26%) of all global emissions. Livestock and fish farms make up almost a third of this (31%), with land used for livestock and human food production adding an additional 24%.
(Source: Our world in Data)

The impact of climate change on what we eat

The biggest impact of climate change will be on agricultural systems, says the IPCC’s February report on impacts: “Climate change will increasingly put pressure on food production and access, especially in vulnerable regions, undermining food security and nutrition.” 

But the essence of the crisis is this: Humanity’s ability to produce food, which “relies on the water, soils and pollination provided by a natural healthy world” as The Guardian succinctly put it in February, is under severe, terminal threat, as global warming progressively weakens soil health, disrupts natural ecosystems, increases disease pressure, destroys marine species, and undermines food productivity overall.

We already have evidence that the threat is real, including in South Africa, with the latest example being the KwaZulu-Natal floods in which hundreds of people have died. 

In recent years the world has already experienced “catastrophic” increases in extreme weather- and climate events, including droughts, floods, heatwaves, storms and rising sea levels, and these have already resulted in millions of people experiencing acute food insecurity and reduced water security. These findings came from the IPCC’s February 2022 report, which UN Secretary General António Guterres called “an atlas of human suffering and a damning indictment of failed climate leadership”.

So how do we limit the damage?

Averting climate disaster will take a lot more than changing how we eat individually – but last week’s IPCC report is clear: What we choose to eat could be a core lever in any actions countries take to contain man-made harms to the environment. 

The bottom line: By eating more plant-based foods and less meat, the world can move the needle on reducing the 26% of carbon emissions that comes from our food systems. 

The IPCC report uses an “Avoid-Shift-Improve” classification for mitigation options. The greatest “Shift” potential (substituting “already existing competitive efficient technologies” for the current, more damaging ones) would come from switching to plant-based diets. 

The greatest “Avoid” potential would come from reducing long-haul aviation and providing short-distance low-carbon urban infrastructure, ie. transport systems. 

The greatest “Improve” potential would come from the building sector, especially increased use of energy-efficient technologies.

A UK comparison of the environmental impacts of a beef burger today with a beef burger in the near-net zero future, shows the ‘net-zero’ alternative ways of producing the burger’s main elements.
(Source: UK Research and Innovation (UKRI)

By 2050, the global population will have grown from 7 billion (in 2010) to 9,8 billion. To feed those extra billions, we will need 56% more “crop calories”, and additional agricultural land equivalent to twice the size of India, said a 2018 synthesis report on how to feed 10 billion people by 2050, sustainably. Despite the fact that there will be nearly 3-billion more mouths to feed, we will still need to reduce annual GHG emissions from agriculture and land-use change from 15 gigatons of carbon-dioxide equivalent to 4 gigatons, in order to hold global warming to 2°C above pre-industrial temperatures. (At the moment we are doing the opposite: Updated data in the IPCC report shows that food systems-related emissions had reached 17 gigatons by 2018.) 

The IPCC report is clear that both supply and demand-side measures are important to reduce “the GHG intensity of food systems”. Realising the full potential of GHG reductions from the food system “requires change at all stages from producer to consumer and waste management”, it says, with integrated food-policy packages that address markets, information, and behaviours. 

Producing and eating less meat will be critical to these efforts, as methane (produced by ruminant cattle) emissions must be reduced by at least one third, the report says, apart from necessary reductions in emissions from land use and feed-crop production.

So, what’s on the menu?

Clearly the world needs to make major changes to what we are growing and producing, for the sake of planetary and human health. And quickly.

Three years before the IPCC officially linked consumption with the climate crisis, the 2019 EAT-Lancet Commission on Food, Planet, Health – a consortium of 37 nutritionists, environment and other experts from 16 countries – delivered a tour de force in the food-systems world.

The commission’s report, Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems, defined a “planetary health diet” calling for major changes in populations’ diets the world over, both to compensate for various forms of poor nutrition in many countries (undernutrition, overweight, obesity) and to benefit the environment. 

The diet was based on nutritionists’ reviews of research on a basic healthy diet made up of whole foods, combined with a set of environmental limits for the production of those foods, including carbon emissions, biodiversity loss, as well as land, water, nitrogen and phosphorus use.

The result was a “flexitarian” diet, consisting of mostly plants, occasionally a small amount of meat or fish, and excluding ultra-processed foods, soft drinks, and most added sugars and fats. The maximum amount of red meat proposed for a 30-year-old man is one serving (100g) per week – “less than one quarter of what a typical American consumes”, an article in the journal Nature says. 

Ultra-processed foods have their own special place in the pantheon of harms done to the environment by industrial food production. The reasons for this include that they are typically made using massive quantities of a small number of high-yielding, dominant crops, such as wheat, corn, soy, and sugar, whose growth is associated with biodiversity loss, which in turn threatens animal and human life.

In addition, the animals used to make UPF including meat usually come from factory-farmed animals that have been fed those same crops. And, because UPF are typically cheap and convenient (which only partly explains their relentless rise in popularity), many people eat them instead of eating whole, fresh or minimally-processed foods. This is already resulting in a global health crisis. 

The EAT-Lancet Commission’s 2019 report visualized a ‘planetary health diet’, a diet designed to provide ideal healthy nutrition, made up of foods from sustainable food systems. The ‘planetary health plate’ is made up of half fruits and vegetables, and half a mixture of plant-based proteins, whole grains, and unsaturated plant-based oils. It also allows for small portions of dairy foods, animal protein, added sugars, and starchy vegetables.
(Source: GoodRx Health, based on EAT-Lancet Commission data)

While experts across the nutrition-science world broadly agreed with the reasoning behind “less meat, more plants”, and it did attract global attention to how humans should eat to save the planet, the EAT-Lancet report was criticised by some. 

One criticism was that it was biased towards wealthy nations – where the average person eats 2.6 times as much meat as people in low-income countries. Another was that it was not a practical solution for many other countries, especially where the foods it recommended, such as eggs, fish, dairy and nuts, are inaccessible or unaffordable for the majority.

Addressing some of these issues, another scholarly article published in March 2022 proposed “regional culturally acceptable low-carbon diets” for China, Europe and the United States that could reduce individuals’ carbon footprints by an average of 20%.  

Taking this further, the UN Food and Agriculture Organisation (FAO) has convened a group to do a more comprehensive, income-sensitive, country-tailored analysis than the EAT-Lancet Report. “They don’t feel as if it was entirely balanced or holistic in its review of the evidence,” said Purnima Menon, from the International Food Policy Research Institute in India. “Let’s go further and make sure we have evidence from around the world.” 

The FAO analysis, which will be published in 2024, is expected to include the critical issues of food security and the sustainability of livestock farming.

Menon affirmed that scientists in low- and middle-income countries are “more concerned about delivering nutrition than preserving the environment,” she told the journal Nature, in a December 2021 article called How humanity should eat to stay healthy and save the planet – but the IPCC’s conclusions definitively recast the nutrition v environment debate as two sides of the same coin. 

The Intergovernmental Panel on Climate Change (IPCC) compared the different potential positive impacts of various diets in reducing carbon emissions from food production. A diet without any animal-sourced food would have the greatest impact, saving 8 gigatons of greenhouse-gases (GHGs) per year. Reducing meat consumption to once a month would still save almost 6 gigatons of GHGs per year.
(Source: Nature magazine)

How many ways can you say ‘emergency’?

Each of the 195 countries that signed their approval of the IPCC’s Mitigating Climate Change report need to put policies in place – immediately – to enable their populations to embrace more climate-friendly lifestyles, including how and what they eat.

This will be complex, and difficult, but not impossible – and the IPCC report offers roadmaps for countries to structure how to do this, for both energy and food consumption.

Professor Tim Lang of the London-based Centre for Food Policy commented by email on the IPCC report: “I was not alone in being disappointed with COP26 [the most recent UN annual climate-change conference] for ducking consumer change as essential for any shift of direction. I know the IPCC is an ‘intergovernmental’ adviser and that governments are deeply reluctant to engage consumers in change, but I see little way for requisite change to come unless consumers are engaged with.”

Lang praised the collaboration of big, non-governmental actors coming together to press governments for changes in consumption – and that is why, he said, the IPCC has placed great emphasis on the different GHG emissions of low- and high- income societies and social groups. “There is no one-size-fits-all policy solution”.

In the meantime, while we wait (and wait) for food-related legislation designed to support South Africans’ healthy eating and minimise our dramatically high rates of overweight and obesity, as well as the diabetes, hypertension and other diseases associated with them, shifting our eating patterns to try to reduce our individual, national and global carbon footprint can be seen quite simply: “Although the average carbon footprint of plant-based meals remains far lower than that of their animal-based equivalents,” wrote UK epidemiology professor Tim Spector in The Guardian in January 2022, “there is something else that has an even lower environmental impact and is far better for our health: it is called “whole unprocessed food”. DM/MC

Notes on the Intergovernmental Panel on Climate Change:

• The IPCC, an international expert panel convened by the United Nations, produces climate-science overviews every six to seven years. Its latest, sixth report, the Sixth Assessment Review (AR6), has three parts: The first, published on 9 August 2021, proved that human-caused climate change was becoming irreversible; the second, published in February 2022, described the impacts of climate change, and the third, published on 4 April 2022, details immediate and longer-term actions needed urgently to mitigate those impacts.
• A concluding “synthesis” report (of the Sixth Assessment Review) will be published in late 2022.

• The IPCC also has a Task Force on National Greenhouse Gas Inventories that develops methodologies for measuring emissions and removals.

• The IPCC’s Mitigating Climate Change report can be viewed in full or in summary at www.ipc.ch. 

• The Mitigating Climate Change report includes chapters on

• Emissions trends and drivers

• Mitigation pathways for the short-, medium- and long term

• Demand, services, and social aspects of mitigation (including food systems)

• Energy systems

• Agriculture, forestry and other land uses

• Urban systems and other settlements

• Buildings, transport and industry (separate chapters for each)

• Cross-sectoral perspectives

• National and sub-national policies and institutions

• International cooperation

• Investment and finance

• Innovations, technology development and transfer
• Accelerating the transition in the context of sustainable development.

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