Circle paper 1

Food System Sustainability Workshops
Rod MacRae

How could the food system sustainably produce, process and distribute food and also generate resilience in the face of climate change?

  • Do we have to sacrifice yields to reduce GHG emissions?
  • Can we reduce non-renewable inputs and maintain production?
  • Do we have to use more land to compensate for any yield declines?


One view is that mitigating climate change and building resilience involve reducing productivity.  We know from the Life Cycle Analysis (LCA) literature (MacRae et al., 2010; 2013; Lynch et al., 2011) that production systems with the following characteristics tend to reduce GHG emissions but equally significantly, many of these elements also build adaptive capacity, primarily because of improved soil quality:

  • Minimal use of synthetic N fertilizer (because of the GHG emissions associated with N fertilizer feedstocks, distribution and manufacturing and the corresponding substitution of animal manure and legumes in rotation)
  • Complex crop rotations (due to better soil cover, higher OM additions, use of legumes)
  • Minimal tillage (but not necessarily no-till, depending on the region)
  • Sophisticated management of animal manure for fertility on mixed farms
  • Lower animal stocking rates (high numbers of animals / ha contribute significantly to overall emissions because of feed demands – and associated synthetic N use – and frequently greater challenges managing manure)

But do we have to sacrifice yields to reduce GHG emissions? Can we reduce non-renewable inputs and maintain production?

When comparing yields on farms with these characteristics to conventional production approaches (MacRae et al., 2014):

  • Field crop yield performance is roughly comparable, except for more significant reductions in some oilseeds (flax and canola)
  • Vegetable yield performance is reduced per vegetable, but overall vegetable production may be comparable based on a more diverse mix of vegetable crops produced
  • Fruit yield performance is reduced, often significantly
  • Dairy and beef productivity is reduced somewhat, often deliberately as producers attempt to minimize metabolic stress on animals
  • Hog and chicken productivity is reduced significantly (largely because of lower stocking rates and different housing and feeding regimes)


Do we have to use more land to compensate for any yield declines? Perhaps, but there are three mitigating factors that have not been well analyzed in Canada.  The first is that our current land use efficiency is low.  Agriculture land is urbanized at rates that do not recognize the value of land for food production. Attempts to reduce urban pressures have not been very successful except in a few regions of the country. Significant percentages of agricultural land are also devoted to non-food uses (industrial applications like ethanol production, building materials and plastics, landscape plants and sod for urban environments, Christmas trees). AAFC (2012) has estimated that 7% of the total value of farm production is devoted to non-food uses, amounting to millions of acres of land.

Secondly, the misalignment of cropping systems with soil quality has led to excess use of synthetic fertilizers (and often pesticides to manage pests associated with excess nutrients in plant tissue and soil).  Unfortunately, synthetic fertilizer, especially nitrogen, creates the conditions for more significant GHG emissions from cropping systems.

The third mitigating factor is that we’re feeding animals food that humans can eat (see paper 3 on dietary shifts).  On a global basis, some 2/3 of agricultural land is devoted to producing animals (Foley et al., 2011).  Some of that makes sense because it is primarily rangeland, though management of such lands is often suboptimal for both animal feeding and environmental stewardship.  Some 40% of it, however, is annual cropping of foods that humans can consume, or on land of sufficient soil quality to devote to other crops for human consumption rather than animal feed.  In Canada, some 80% of barley, 35% of oats and 60% of corn production goes to feed animals. There are also many areas, away from the dominant cropping regions, that are significantly underutilized for forages, hay and pasture because they are disfavoured by the dominant agricultural economy and the associated loss of infrastructure.  For example, the loss of regional abattoirs makes it more difficult for beef producers to operate farms based on forages, or on class 4-7 land that is often more remote from large urban centres.  A more sustainable regional strategy involves aligning land quality with specific uses. This also is consistent with an input reduction approach, since the misalignment of land quality with production has become more acute in the era of synthetic pesticides and fertilizers.  Lost productivity associated with simplified crop rotations and soil erosion remains a significant issue. However, at the moment, Canada does not have mechanisms to generate landscape level changes of this kind.


The modelling work has yet to be done on all these factors, but with less land devoted to industrial crops, and reductions in animal densities and changed feeding regimes (more hay and pasture for ruminants, more co-products from processing and diverted “waste” for omnivorous scavengers like poultry and hogs), it may be that any yield declines on a national basis associated with shifts to mitigating and resilient systems can be compensated for.  It could be achieved without creating new agricultural land, but rather repurposing existing production areas.  Better controls on urban boundaries (see for example, Desjardins et al., 2011) would also help significantly.

Can combining mitigation and resilience be profitable for farmers? The literature suggests yes, largely because of the significant reduction in input costs.  Comparisons of conventional and sustainable systems typically find input savings of 1/3 for the sustainable system.  So even with yield declines, the net is an improvement.  If the sustainable products also have premium markets, e.g., organic, high standards of animal welfare, local supply chains, then the net situation can be significantly better than under conventional management (MacRae et al., 2014).  Opportunities for emission reduction incentives, such as generating and selling carbon offsets, could further increase the net benefits for farmers with more sustainable practices.

What are the implications for processing and distribution?   Although production is the largest contributor to GHG emissions, the rest of the supply chain is also very significant, related particularly to heating, cooling, transportation and food waste (MacRae et al., 2013).  The improvements generated at the farm level can be diminished by the failure to also make changes downstream.  Shorter supply chains, more efficient heating and cooling motors, changes to retail store designs and procedures to reduce energy and food waste (MacRae et al., 2016) and promotion of sustainable products across the supply chain would all help reduce emissions.

By shifting multiple variables concurrently, it is feasible to both mitigate GHGs and become more resilient and profitable.


Desjardins, E., J. Lubczynski,, and M. Xuereb. 2011. Incorporating policies for a healthy food system into land use planning: the case of Waterloo Region, Canada. Journal of Agriculture, Food Systems, and Community Development 2(1):127-140

Foley, J. A., N. Ramankutty, K. A. Brauman, E. S. Cassidy, J. S., Gerber, M. Johnston, N. D. Mueller, C. O’Connell, et al. 2011. Solutions for a cultivated planet. Nature 478:337–342.

Lynch, D., R. MacRae and R. C. Martin. 2011. The carbon and Global Warming Potential impacts of organic farming: does it have a significant role in an energy constrained world?  Sustainability 3:322-362.

MacRae, R.J., D. Lynch, and R.C. Martin. 2010.  Improving the energy efficiency and GHG mitigation potentials of organic farming and food systems in Canada.  J. Sustainable Agriculture 34(5):549-580.

MacRae, R.J., V. Cuddeford,  S.B. Young and M. Matsubuchi-Shaw. 2013. The food system and climate change: an exploration of emerging strategies to reduce GHG emissions in Canada. Agroecology and Sustainable Food Systems 37:933-963.

MacRae, R.J., D. Lynch and R.C. Martin. 2014, Will more organic food and farming solve food system problems?  Part I: Environment. In: R.C. Martin and Rod MacRae (eds.). Managing Energy, Nutrients and Pests in Organic Field Crops. CRC Press, Boca Raton, FL pp. 307-331.

MacRae, R.J., A. Siu, M. Kohn, D. McCallum, M. Matsubuchi-Shaw, T. Hernandez Cervantes and D. Perreault. 2016. Doing better with what we’ve got: strategies to reduce food and resource waste in the Canadian food system.  Canadian Food Studies 3(2):145-215.