On our journey through the food sustainability landscape, we’ve had an introduction to what the food system is and to some of the major social and environmental impacts which make it unsustainable. Our minds naturally turn to the question, “Well, we all have to eat! How can we address these problems and make our food systems sustainable?”.
The truth is, there are no easy answers, because of the vastness and multi-scaled complexity of the global food system, because uncertainties abound, and because food is not just fuel for our bodies but also a deeply important part of human cultural expression. Furthermore, changing the food system will require that we effect changes not just within agriculture, but within energy and transport sectors as well, and within manufacturing, processing, and retail spaces. And, ultimately, envisioning and committing to a replacement for our current growth-obsessed capitalist economic system is a necessary precursor to true, deep, sustainability.
This is all fine and good, but it will take time and international cooperation. What can we do today? While it won’t get us all the way to the finish line, there are things that we as individuals can choose to do that can significantly reduce the environmental burdens associated with our food systems, and it begins with what we choose to put on our plates.
Comparing the environmental impacts of different food categories
Systematic analyses of the environmental impacts of plant and animal food products over the past 20 years have consistently come to the same conclusion: the production of animal-based foods is far more resource-intensive and contributes far more to environmental impacts than the production of plant-based foods. Indeed, the production of meat, fish (aquaculture), eggs, and dairy uses approximately 83% of the world’s farmland and emits 56 to 58% of food’s various pollutants to air, water and soils. These foods, however, provide only 37% of global protein requirements and 18% of our caloric intake.
Among animal products, ruminant meats (beef, lamb, goat) and dairy products are the most significant sources of impacts. Researchers have reported that, per gram of protein, the most impact-intensive ruminant meat production systems may result in 250 times more greenhouse gas emissions than legume production. And as a group, ruminant meats contribute 20-100 times more to environmental impacts than plant foods, on average. Eggs, dairy, poultry, and pork all have lesser impacts than ruminant meats, as do many seafood products, but these foods are still considered medium contributors to impacts compared with plant-based foods.
There are several reasons that animal products contribute more to impacts than do other foods. Several researchers have pointed out that animal production systems have the inherent problem of inefficient feed-to-edible protein conversion ratios (greater than two for most animals). In addition to this inherent inefficiency, it is also the case that global deforestation for agriculture is being driven largely by crop production for animal feed and for pastures. This land conversion results in the loss of large amounts of carbon formerly stored in the soil and the release of carbon with the decay and burning of cleared forest plant material. Also, emissions from slaughterhouse effluent and meat processing mean that animal product processing results in greater pollution than the processing of most other food products. Finally, direct emissions of methane from ruminant enteric fermentation (which alone accounts for an estimated 32% of agricultural greenhouse gas emissions) and manure storage, as well as from aquaculture ponds are significant sources of greenhouse gases.
There is also variability in environmental impacts among plant-based foods. On average, with respect to potential contribution to global warming, field-grown (i.e. not grown in heated greenhouses) vegetables and fruits, as well as cereals (except rice) and pulses contribute relatively minimally to impacts. Among plant food production systems, rice fields contribute the most to impacts (except land use), contributing even more to global warming than heated greenhouse production.
Comparing the environmental impacts of different dietary patterns
Since the many models comparing the environmental impacts of different food categories have all shown that animal-based foods contribute orders of magnitude more to impacts than do plant-based foods, it is not surprising that studies which compare different dietary patterns conclude that the potential for individuals and nations to reduce food-related environmental impacts may be substantial. This is particularly true in countries like Canada where large amounts of meat and dairy are consumed.
The vegan diet is modelled as having a significantly smaller contribution to environmental impacts than the typical high-income country’s diet. For example, in a recent review of the literature, I found that researchers report a potential reduction in greenhouse gas emissions resulting from a switch to veganism ranging from 25-74%. Eutrophication is reported as potentially reducing by 37-76%, acidification by 45-90%, and land use by 40-76%. Interestingly, for countries like Canada and the US where meat consumption is significantly higher than the global average, a switch to veganism could result in a reduction of as much as 61-73% across the various emissions to air, soil, and water.
But is it realistic to just say “Go Vegan!”, and leave it at that? Not really; there are many complex cultural, nutritional, social, and economic reasons why veganism may be a difficult sell for people. So I say, do what you can! A switch to ovo-lacto vegetarianism (vegetarians who eat small amounts of dairy and eggs) was modelled as potentially reducing greenhouse gas emissions by 25-55%. Eutrophication potential is reported as reducing by 14-55%, acidification by 14-69%, and land use by 14-51%. Also, if you’re a person who eats animal foods daily or multiple times daily, significantly reducing your animal food intake can make for big improvements. A commonly modelled scenario is a 50% reduction in meat intake, and these studies show that a moderate to large reduction in impact is possible. This potential reduction depends, of course, on how many animal-based foods you were eating before the 50% reduction. With respect to greenhouse gas emissions, a potential reduction of 17-59% was reported. Potential reductions of 20-37%, 29-39%, and 24-51% were reported for eutrophication, acidification, and land use, respectively. Or maybe you’d like to go a little further, and choose to eat animal products only two days a week (or six meals a week)? If so, this chef has some great advice to get you started.
It’s important always to keep in mind that individual actions alone will not get us to a sustainable future. It is imperative that we have international cooperation to bring about the systems-wide overhaul required to meet the needs of a growing population without undermining the health of this beautiful planet that we all call home. That said, while we’re fighting for better policy and for governments to take urgent and radical action, we also have the responsibility to lead by example, to signal our readiness and willingness to make the changes necessary, and to do all we can to reduce the impacts of our lifestyles. We now know that the provisioning of our food has a massive impact on the planet, and so the onus is on us to be mindful and intentional about what we put on our plate. It’s just one of many lifestyle changes that can be made, but it matters a lot.
Photo by Anna Pelzer on Unsplash
