Food production and climate change

Dr Richard Newton, Institute of Aquaculture, Faculty of Natural Sciences

Food production is a significant contributor to greenhouse gas emissions, but as consumers we have a degree of power to make cleaner, greener choices. In this mini lecture Richard Newton, from the Institute of Aquaculture, explores the topic of sustainable food.

Hello, I am Richard Newton from the Institute of Aquaculture. Welcome to my lecture on food production and climate change. 

The effect of human activity on the world’s climate is beyond doubt as highlighted in the recent IPCC climate change report. Humans need radical change to reduce the inevitable impact that climate change will have on our societies, and the environment in which we live and interact.  The food we eat, and how it is produced, is a huge contributor to greenhouse gas emissions, and today I want to talk about the impact from how our food is produced and how choices we make can improve our impact on climate change.  

In 2009, the concept of planetary boundaries was introduced. It was calculated that we were currently using double the resources that could sustainably be used. That is, we would need two planet Earths to sustain our current activities. Since Rockström’s ground-breaking article, the population of the Earth has increased by around a billion people.Population will mainly increase in developing countries such as in Africa and in some parts of Asia. So, we need to feed more people, but also more affluent people, with demands for higher quality and greater quantities of nutrition. 

As developing countries achieve food security, their attention turns to providing diversity and quality for more affluent markets. So, we face a double challenge of providing the needs of more people but a lot richer people too. 

A large part of seeking a more nutritious diet is to consume more animal protein including beef, pigs, poultry, dairy and seafood. The production of all these foods continues to grow and consume resources.  

The contributions of livestock to climate change come in various ways throughout the supply chain, including emissions from managed soils, fertiliser manufacture and application, land use and land use change, electricity, heating, and transport, and finally waste management. All of these stages add up to a range of pressures on raw material inputs and associated emissions. 

The first thing to know is that the supply chains for livestock production are global. Around 75% of feed ingredients for Scottish salmon by volume are sourced from outside of the UK. Although that does not necessarily mean those ingredients are unsustainable, it does mean we have less control over how they are produced.  

In some cases, such as soy and palm oil there are concerns over the expansion of production into rainforests and other sensitive areas, risking damage to ecosystem structure and biodiversity loss. In addition, Land Use Change contributes to carbon footprints through loss of carbon dioxide sequestration, and release of carbon from soils after the clearance has occurred. The subsequent application of fertilisers and tilling also adds to greenhouse gas emissions. However not all soy or palm is associated with rainforest clearance such as certified sources. Feed producers can improve their sustainability by turning to such sources.  

By contrast, marine ingredients have comparatively low carbon footprints but any expansion is restricted because fisheries are at their limit of sustainable supply.  

In the institute of aquaculture, we investigate the sustainability of aquaculture systems all over the world. Aquaculture is extremely diverse, much more so than terrestrial production, ranging from unfed mussels, extensively produced carps and other omnivorous freshwater finfish, to intensively produced salmon and other carnivorous marine fish. Compared to terrestrial species, most aquaculture species are extremely good converters of feed, resulting in lower carbon footprints. However, in the case of most fed finfish, the procurement and manufacture of feed accounts for the vast majority of the carbon footprint. Feed ingredient procurement is complex and their sustainability credentials not always clear, with many trade-offs between carbon footprints and other impacts such as water use, land use and impacts on ecosystems. 

While feed contributes to over 90% of impacts within the supply chain and that supply chain spreads all over the globe, the impacts from aquaculture production also occur far from the point of production. More than 50% of impacts from Scottish salmon production occur outside the UK.  

In response to the need for more sustainable ingredients for feed supplies, a large number of new “novel” ingredients are being developed. These include insect meals, bacterial single cell protein, algal biomass and oil, and the by-products from fish and meat processing. As they develop, there are many challenges regarding legislation, logistics and acceptability in different areas. They are often touted as sustainable alternatives and the food of the future, but the reality is less clear. 

Many of those receiving most attention are still at pilot stage and are inefficient to produce, requiring a lot of energy to process. Single cell proteins and micro algae are especially intensive and have much higher footprints than most fishmeal and sustainable soy sources.  

However, a large proportion of the food we produce is wasted at all stages from production, storage, distribution, retail and consumption. As well as reducing the amount of waste, it is important to recycle these wastes effectively. 

Legislation is very strict over what can or cannot be done with animal by-products. Insects are natural and efficient converters of organic matter such as manure, catering wastes and dead animals, but none of these are allowable under current legislation. Much of the legislation is built on the precautionary principle as a result of BSE and other animal health crises. This has also fed into public opinion and reflected through sensationalist media. 

However, aquaculture is very diverse and the animals that are produced have very different physiologies from cattle and even one another. If we are serious about cutting waste and being resource efficient, then these are exactly the type of locally produced wastes that need upcycling in appropriate industries. The most efficient use is directly in feeds and if used safely, by-products are nutritious, efficient, and low in environmental footprint. Some may also say they are much more natural than plant and other alternatives when fed to a carnivorous fish species such as salmon and trout. By integrating food production systems waste is cut throughout the supply chain and the carbon footprints of all our food products can be reduced. 

The University is continuing to work on evaluating the sustainability of different aquaculture production systems and their supply chains using Life Cycle Assessments and value chain analyses. We continue to try to drive more sustainable practices at the commercial and policy level and to communicate the benefits of sustainable aquaculture across the globe to a wide range of audiences including vulnerable communities and relatively more privileged like ourselves. I hope that when you buy food you will stop for a moment to think about how and where it is produced and the lives of the people who have been involved in its production.  

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