Share this page:
Other services (opens in new window)
Sets a cookie

The Food Climate Research Network

March 2010

Developed countries need to reduce their GHG emissions by 80% or more

One of the hardest challenges facing scientists is to grow more food using less energy and with fewer emissions. Unfortunately, it is now well-recognised that agriculture, as well as food storage, transport, and distribution, are major producers of greenhouse gases (GHG).

Estimates vary, but agriculture alone can account for 7% of the UK’s GHG emissions, but that figure excludes fertiliser use [ref 1]. When fertilisers are included, the figure rises to 10-12% [ref 2]. The UK figure rises again to 18% when all stages in the food life cycle are included, from production to transport, consumption and disposal [ref 3].


Modern agriculture produces lots of greenhouse gases.
Image: iStock

Worldwide, the Intergovernmental Panel on Climate Change (IPCC) makes agriculture responsible for 10-12% of global GHG emissions [ref 4]. However, the European Union clocks the food chain as responsible for up to 31% of total EU emissions [ref 3]. The high variance in the figures relate to methodological differences, and whether factors such deforestation required to clear land are included, which adds CO2 to emissions.

It’s a complex picture, but the Food Climate Research Network (FCRN) aims to increase our understanding of how the food system contributes to GHG emissions, and how they can be reduced. Funded by the Engineering and Physical Sciences Research Council (EPSRC) and the Department for Environment, Food and Rural Affairs (Defra), FCRN is based at the University of Surrey and has undertaken its own research into the food chain since its inception in 2004.

FCRN researcher Tara Garnett says an important part of her work is sharing and communicating information on food-climate matters. “It’s open to all,” she says.

It’s important work. Developed countries need to reduce their GHG emissions by 80% or more, and the UK is legally committed to acting following the 2008 Climate Change Act.

Life Cycle Analysis

One way to calculate the energy footprint of food is by Life Cycle Analysis (LCA), which measures a product’s energetic cost and environmental impact at all stages in its production, storage, transport, consumption and disposal. Such metrics can be used to compare, for example, lettuce grown outdoors in Spain during winter and driven to the UK against lettuce grown under lights in the UK. In this way, LCA analysis has shown that local may not always be the best option (see ‘Food miles, climate change and consumer choice’).


Meat and dairy products increase emissions.
Image: iStock

Similarly, LCA has shown that livestock products such as meat and dairy products produce significantly more GHGs than other food groups. Furthermore, most of the environmental impacts occur at the agricultural stage (through nitrous oxide and methane emissions, rather than carbon dioxide), with processing, transport and retail playing more minor roles.

The UK Government has developed LCA into a standardised method for calculating GHG footprints called the PAS 2050 (Publicly Available Specification), which is slowly being adopted by manufacturers so that one day an agreed ‘carbon label’ might inform UK consumers’ purchasing decisions.

However, whatever system is agreed will surely change with further research because scientists are aware of LCA’s limitations, such as second order impacts of products or landscape changes, which also need to be quantified.

Garnett says LCA’s limitations are that it provides numbers, but the context, quality of land, human behaviour and assumptions about patterns of demand, and ethical considerations such as animal welfare and the value of biodiversity are not taken into account. “It’s a good tool, but it’s only a tool,” she says.

Food versus feed

Research by the FCRN has tackled other tricky issues, such as feeding food to livestock that could be given to people, or the ‘food versus feed’ argument. Feeding grains to an animal will always be less efficient than feeding a person the grains because energy is always lost when it passes through a trophic level in an ecosystem. Moreover, it happens on a vast scale. The United Nations Environment programme has calculated that animal feed grown worldwide for livestock could feed 3.5Bn people [ref 3].


More grains, please!
Image: iStock

But this does not mean that all meat production is necessarily inefficient. Grazing animals can convert grasses that people cannot eat into meat which they can, and many parts of the world that are not suited to agriculture are ideal for grazing. Other grazing animals can convert grass, inedible crop residues and household waste into meat, milk, blood and eggs. Animal parts can also then be used for fertiliser, and for tradable items such as furs and wool.

Meat is also a valuable source of essential nutrients, especially in parts of the world where people have limited diets. Although all nutrients (apart from vitamin B12, which can be obtained from yeast) can be obtained from a varied plant diet, nutrients are often more bioavailable from meat. Iron is more easily digested from red meat than spinach for example.

Production of grains for livestock also has a ‘buffering’ effect on food prices. Because more grain is produced than required for human consumption if harvests in some parts of the world fail, then there is, in theory, an excess that can satisfy demand and prevent food prices soaring. Inadequate grain stocks were one the reasons that the food price spike of 2008 was so severe and felt around the world.

But arguments against the real effectiveness of the buffering effect reveal more complexity. In richer nations, people consume more meat. When food prices rise, rather than abandoning meat, people tend to consume cheaper meats such as pig and poultry. But these are the livestock that consume more – not less – cereals in their production. Therefore, the buffering capacity of the extra grains is not released onto the market for consumption by poorer people (animal grains are of sufficient quality to feed to people).

Therefore, the buffering argument may only hold for certain crops, fed to certain animals in certain situations – it may even change year on year. Intensive farming systems in particular, are said to have the least ‘slack’ to accommodate price fluctuations.

References

  1. The future of our farming
  2. Food Matters: Towards a Strategy for the 21st Century
  3. Livestock-related greenhouse gas emissions: impacts and options for policy makers
  4. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007 (PDF)