Interview taken from the 2018 College Newsletter
Whilst a doctoral student in environmental science at Queen’s, Joseph Poore published a landmark global study in the journal Science. The study was a major piece of research into the environmental impact of agriculture, examining data from over 38,000 farms across 119 countries.
The study used this evidence to build an integrated framework for monitoring and managing food’s environmental impacts, but ultimately points to one simple way humans can have a transformative effect on the environment – by avoiding meat and dairy products.
Albert Einstein said ‘nothing will benefit human health and increase the chances for survival of life on Earth as much as the evolution to a vegetarian diet’. Poore’s research provides extensive evidence to support this claim. In widespread media coverage, he said: ‘A vegan diet is probably the single biggest way to reduce your impact on planet Earth, not just greenhouse gases, but global acidification [of terrestrial ecosystems], eutrophication [the build-up of nutrients in water bodies which depletes biodiversity], land use, and water use.’ Poore’s research was the result of a five-year project, which initially began as an investigation into sustainable meat and dairy production. He stopped eating animal products himself after the first year. We asked him about the scope of his research, its implications, and some of its unexpected results.
What made you choose to study this area?
I wanted to challenge my own consumption of animal products. I wanted to understand if there were low impact, sustainable producers out there and, if so, what could be learned from them. Originally, I was looking at just two environmental indicators, land use and greenhouse gas emissions, but this rapidly expanded to build a comprehensive picture across most of the major environmental impacts of agriculture.
Agriculture is the single biggest human user of land. It accounts for ~95% of human land use and covers ~43% of the world’s ice and desert-free surface area. It accounts for a third of the world’s greenhouse gas emissions, about a third of the world’s air pollution, 80% of the world’s water pollution, and drives around 95% of the world’s water scarcity. It sits at the middle of most of the world’s major environmental problems.
You became vegan a year into your research; was there a particular thing that prompted this or was it the result of studying the accumulated data?
Firstly, it was the fact that animal products create such markedly different environmental impacts when compared with substitute vegetable products. And this isn’t necessary to sustain our way of life: the same proteins and calories can be sourced at a fraction of the environmental cost.
Secondly, as I was doing the research, I quickly became aware of a lot of the issues surrounding factory farming. By 2050, it’s estimated that to meet demand, the world will need to produce a trillion litres of milk and 500 billion kilograms of meat per year. This is a 40% increase on today’s figures. Almost all of this will come from intensive farming in the developing world at a great cost to animal welfare.
Were there any unexpected findings in your study?
Yes, there were quite a few unexpected findings. Firstly, we know that agriculture is incredibly diverse. There are 570 million farms all around the world, all using different practices, producing on different soils and in different climates. This creates high variability in environmental impact. For example differences in emissions between two beef producers can exceed 1,100%. However, all this variability fails to translate into animal products with lower impacts than substitute vegetable proteins. Put simply, it will always be better to change what you consume rather than try and purchase sustainable meat or dairy.
Another surprise was with aquaculture. People thought these systems were relatively low emissions, but actually, with the new model that we built to look at methane, aquaculture can create more methane than from cows when you take into account the carbon that accumulates in the anaerobic area at the bottom of ponds. Another unexpected finding was that pasture grazing systems don’t necessarily deliver lower environment impacts than feed-based systems.
The new data also showed that cheese has a higher environmental impact than poultry, pork, farmed fish or eggs. The reason for that is that you need ten litres of milk for one kilogram of cheese; in turn, to produce one litre of milk, you typically need over two kilograms of feed. On top of that, you have the emissions from the animals that produce the milk themselves (eneric fermentation and manure management).
Why do you think there’s resistance against, and even hostility towards, veganism?
I think there’s a large element of self-sacrifice that many people find off-putting. However, we did explore a second scenario, which is a 50% reduction in animal product consumption. If we reduced our consumption by 50%, by avoiding the highest impact producers, then we can achieve three quarters of the potential reduction on emissions that are associated with a completely plant-based diet. This scenario would rely on getting labels onto products that show how high or low impact products are and we’re a long way off this at the moment. A system of labels would also have the advantage of creating a positive loop – suppliers would have to consider the impact, encouraging them to source product more sustainably, and, in turn, the producers would have to monitor their environmental impact.
Dr Joseph Poore is now Director of the Oxford Martin Programme on Food Sustainability at the University of Oxford.
