Dr. Colin Sage &
Dr. Maria Grazia Quieti

“The global alteration of the nitrogen cycle leads to many different, cascading effects on human and ecosystem health but arguably it is one that has least recognition amongst the general public,” noted Dr. Sage, author of the acclaimed text, Environment and Food (Routledge, 2012) and co-editor of Food Transgressions: Making sense of contemporary food politics (Ashgate 2014).

Ironically, it used to be a lack of nitrogen in the soil that limited how much food could be produced and thus, the population of mankind. However, once that problem was solved – in the early 1900s with the development of man-made fertilizer -- feeding a growing population seemed to have no bounds.

Now, not only have those bounds been reached, they have been surpassed -- far exceeding what the planet can support. The ecological damage caused by nitrogen pollution includes: depleting soils of calcium and potassium needed for long-term soil fertility, increasing acid rain, and creating coastal water ‘dead zones.’ 

Exploring this problem and what can be done about it was the focus of Dr. Sage’s lecture, “The global food system, nitrogen and the metabolic rift: Farming – and eating – within planetary boundaries” at the Italian Geographical Society in Rome, on Jan. 30. Dr. Sage is a Senior Lecturer at the Department of Geography at University College, Cork, Ireland. His lecture was organized by Maria Grazia Quieti, director of AUR’s Master in Food Studies program and a member of the Italian Geographical Society.

Dr. Sage raised the often-asked question: “How shall we feed the world of 9 billion people by 2050?”

The answers thus far have been more technology and more chemicals, but as he pointed out “the manner of our success is no longer a pathway.”

Those in attendance – including scientists and food policy experts – agreed with his statement. In the Q&A that followed, the consensus was that there are no easy solutions, but there needs to be more awareness of the issue. Some answers may be found as nations try to reclaim their food culture from globalization and food policy planners look to shorten the distance from farm to table. However, as far as each individual is concerned, a good place to start would be to eat less meat – if not for environmental or ethical reasons – then for better health. 

The following is taken from Dr. Sage’s handout about the lecture. 

A victim of our own success
The development of the global food system has transformed the volume and variety of foodstuffs made available to consumers in many regions of the world. The application of science and technology to seeds, other agricultural inputs and to farming practices has resulted in extraordinary productivity in primary production.
Yet the supply of cheap food commodities from all over the world has come under increasing scrutiny across a number of fronts. Food security and health specialists highlight the triple burden of malnutrition: continued hunger & insufficient intake; mal‐consumption and obesity; and micronutrient deficiencies.
Meanwhile, environmental scientists draw attention to the growing ecological costs arising from the industrial agricultural model.  These include: driving land‐use change and loss of biological diversity (from plant genetic resources to entire habitats); the depletion and contamination of surface and groundwater resources; the degradation of ecosystem services, including pollinators; and a significant and rising contribution to climate change.
Breaching the planetary boundaries
The framework of planetary boundaries as set out by Rockstrom et al (2009a, 2009b) and by Steffen et al (2015) draws attention to nine key Earth system processes each of which are being affected by human activity. The framework attempts to establish critical thresholds that represent limits to a safe operating space for human societies.
It is clear from the framework that three of the nine processes – climate change, biodiversity loss, and nitrogen and phosphorous flows ‐- have clearly breached their respective boundaries.
While climate change has arguably become the single most important issue de nos jours and one
around which there is probably greater scientific consensus of a boundary limit (350‐450 ppmv C), other processes are less easily quantified or may be less directly connected to specific drivers.
One that can be attributed to anthropogenic activity, not least because it has come to underpin the survival of the species through food production, is that of the biogeochemical flow of nitrogen.
The development of the Haber-Bosch process in the 20th century -- to synthesise atmospheric nitrogen (N2) into the form of fertiliser and thereby provide a source of reactive nitrogen (Nr) that could be taken up by crops – has had an utterly transformative effect on the world. 
Together with the subsequent development of fertiliser‐responsive high yielding seeds, it has been argued that without the Haber‐Bosch synthesis only about 40 percent of the world’s current population could be fed (Smil 2002).

AUR students anticipating the lecture

Demand for meat accelerates problem
Yet, it has been estimated that only 47 percent of the reactive nitrogen applied to croplands worldwide is converted into harvested products and that more than half is lost to the environment.  Globally, humans currently ingest c. 20 Tg N yr‐' in their food, most of which subsequently enters the environment. A further 100 Tg N yr‐' involved in food production, but which never enters a human mouth, is also released to the environment.
Such figures demonstrate how significant is the contribution from food production and consumption (Galloway et al 2002).
Moreover, the continuing expansion of animal feed cultivation to satisfy rising demand for meat is accelerating this problem not least due to the inefficient conversion of vegetal to animal protein such that animal food production contributes c. 63% of reactive N losses (Lassaletta et al 2014a).
A further dimension of this problem is the separation of feed production from animal rearing such that we see marked regional contrasts. For example, around three‐quarters of Europe’s protein‐rich animal feeds are imported from South America making attribution of environmental burdens – GHG emissions, land-use change as well as biogeochemical flows – more complex.
These planetary scale processes, especially those that are approaching – or even transgressing – limits, capture something of the ‘metabolic rift’ as originally conceived by Karl Marx. Given his concern for the robbing of soil fertility by capitalist agriculture, it seems apposite to consider the way in which the apparently successful ‘solution’ has served to disrupt a key global nutrient cycle.
If we are to recover and restore planetary balance in this particular area, then it becomes clear that we must examine the potential for transition towards an agroecological model of food production that makes greater use of local nutrient cycling pathways.
Biography of Dr. Sage
Colin Sage has worked on the interconnections of food, agriculture and environment throughout his academic career. After a sojourn in the Himalayas, he undertook his PhD on changes in highland agriculture in Bolivia (University of Durham 1990), which included a side project on the cocaine economy. Long interested in the issues around food and livelihood security, Sage has conducted research in Mexico and Indonesia and undertaken contracts to evaluate projects in Ethiopia, Pakistan and Central America. More recently he has worked with artisan producers in Ireland documenting the development of alternative food networks as well as working with urban community food initiatives. From there it was a natural step to help form the Cork Food Policy Council which he chairs.