SUSTAINABILI- DIT Sustainable eating

Did you know that food production accounts for 26% of global emissions?

That dark chocolate accounts for more CO 2 equivalents per kilogram than lamb, pork or farmed fish?

That the production of some nuts is carbon negative?

My interest in sustainability started in high school as the climate crisis began to take up more and more political airtime. Three years ago, I decided to go pescatarian for ‘environmental reasons’. Admittedly, I knew very little about these reasons, and had grown bored of steak as my go-to protein. I am writing this now to analyse some of the arguments that a younger me blindly accepted.

For the purpose of this article, we’ll be defining ‘sustainability’ as the ability of a current practice to continue to fulfil its role into the future. This may be the ability of the agricultural industry to continue food production without detriment to the environment, an individual to consume a particular diet without risking malnutrition, or the meat industry to continue particular practices within the context of their consumer’s ethical standards. Without further ado, let’s take a deep dive into sustainable eating!

Regardless of how you do it, putting food on the table uses resources and produces emissions. The World Resources Institute suggests we have a 56% gap between crop calories produced in 2010 and those needed in 2050. If we are to sustainably feed the projected global population of 10 billion humans in 2050, we have a lot of work to do.

Currently, half of the world’s habitable land is allocated to agriculture; 77% for grazing and animal feed, and the remaining 23% for crops (excluding producing feed for livestock.) While livestock accounts for the vast majority of agricultural land use, it may come as a surprise that the non-livestock crops provide the majority of calories and protein.

There is also the push to redefine the metrics we use when discussing our agricultural product, from mass yield (tonnes per hectare) to the nutritional yield (people nourished per hectare). A 2013 analysis of 947 million hectares of cropland found that we produce enough raw plant calories to feed 10.1 people per hectare on average. However, after accounting for plants used by other industries (e.g. biofuels) and nutrients lost in livestock metabolism, the cropland only contributed 6 people per hectare to the food system.

As the global population grows, I do wonder how sustainable our current practices are. When habitable land is a finite resource, what measures will we take to increase nutritional yield?

When people talk about the environmental impact of agriculture, they are usually talking about three main points: land use, freshwater use, and greenhouse gas emissions. Energy generation is currently the largest contributor to total global greenhouse gas emissions. Transport makes up a large chunk of that, making up 16% of total emissions. The greatest surprise for me was seeing that food far outweighs transport, accounting for 26% of emissions across agriculture, transport, and retail. If we continue our current approach towards diet, we risk breaking our 2 celcius atmospheric warming threshold by the year 2100.

Beef is one of the highest contributors to our food emissions, coming in at 99kg of carbon dioxide equivalents per kilogram from beef cattle, or 33.3kg from dairy cattle, where the emissions are shared amongst other products. Non-ruminant livestock such as pigs and poultry produce considerably less emissions at 12kg and 10kg respectively. Cutting methane emissions through changes in livestock feed and farming practices will considerably improve our climate forecast. There is also the argument that buying local reduces the lifespan emissions. However, much of the current literature would suggest this has a far lesser impact than the choice of food itself. International freight can be surprisingly efficient when their emissions are shared across a large volume of food and the majority of transport emissions are often accumulated in the final kilometres, travelled by road. The mode of international travel can also make a huge impact – flying can produce up to 50 times more kilograms of carbon dioxide equivalents per tonne per kilometre travelled than shipping. A multi-faceted approach to reducing food-related emissions, including choice of foods, locality of produce and reducing waste, is essential to reducing our food footprint. Both individuals and big decision-makers need to consider these aspects when forming strategies to reach our climate goals.

The sustainable food debate has more than its fair share of nuances and disagreements. The challenges to our food production systems are far more extensive than what can fit into a thousand-word article. I strongly encourage you to continue your own research, and look more into the references for this piece – just keep in mind that every author has a bias.

If you’re more interested in casual conversation, the Adelaide Sustainability Association (ASA) might be the group for you. See our details below to follow our social media pages, get involved in our committee, & kick off those interesting conversations.

The Adelaide Sustainability Association (ASA) at the University of Adelaide are a social group interested in learning more about sustainability and getting to know likeminded students. You can learn more about the ASA & chat about our Sustainabilidit articles via our social media channels: @ Adelaide Sustainability Association on Facebook @instainable on Instagram.

Ranganathan, J, et al. (2018). ‘How to Sustainably Feed 10 Billion People by 2050, in 21 Charts’, World Resources Institute.

Shepon, A, et al. (2016). ‘Energy and protein feed-tofood conversion efficiencies in the US and potential food security gains from dietary changes.’ Environmental Research Letters.

Cassidy, E, et al. (2013). ‘Redefining agricultural yields: from tonnes to people nourished per hectare.’ Environmental Research Letters.

Ritchie, H, et al. (2022). ‘Environmental Impacts of Food Production’, Our World in Data.