Globalisation is not only a matter of clothing and mobile phones.
Long-distance worldwide shipping of food commodities has also increased
tremendously over the last few decades. Lassaletta et al.
<http://link.springer.com/article/10.1007/s10533-013-9923-4> (2014)
estimate that one-third of all proteins (a proxy for the nutritive
potential of foodstuffs) produced globally are redistributed through
international trade. Thus a recent study in France shows that the total
volume of long distance commercial exchanges of food commodities, mostly
originating from far away, account for over twice the national agricultural
production (Le Noé et al., submitted).
However, the positive value of a globalised food supply is being actively
questioned. In industrialised countries, a citizens’ movement has arisen,
sometimes supported by local public authorities, seeking to promote a local
food supply. This movement aims to reclaim control of nutrition, re-create
social links often destroyed by the extent of mass distribution, and
develop the local economy.
Weeding maize in Burkina Faso (courtesy Marion Fleury, 2013)
Developing countries are also attempting to strengthen their local food
supply and recover part of their food sovereignty
<http://www.foodsovereignty.org/> lost by decades of open market policies.
At both the community and national scales, the objective of localising the
food supply has become an important social and political focus.
However, shipping cereals, soybeans or other foodstuffs in containers
across the oceans is very inexpensive. Many studies have shown that this
does not in itself have a large environmental imprint compared to the
impact of agricultural practices themselves. Converting chemical
agriculture to organic practices, which eliminates pesticide pollution and
gives rise to lower nitrogen losses to the environment, would have much
greater impact on the environment than reducing “food miles” (Weber and
Matthews, 2008
<http://mmm.comuv.com/wordpress/wp-content/uploads/2010/06/Food-Miles-and-the-relative-impacts-of-food-choices-Weber-and-Matthews-2008.pdf>
).
Economists have therefore proposed the comparative benefits of producing
each type of food on the most suitable land and relying on international
trade to redistribute them. These are among the sceptics claiming that
targeting food self-sufficiency and sovereignty compromises the
environmental optimum that an open global market economy might offer.
*Our food system model*
Based on FAO data, we established a model of the agro-food system of 12
regions of the world in terms of protein fluxes across arable land,
grassland, livestock and human nutrition. Besides showing the substantial
geographical disparities of the current world food system, the model allows
one to explore the possibilities of meeting the food demand as estimated
for 2050, based on demographic projections (9.25 billion inhabitant
globally). Included in the model are nitrogen (N) losses to the environment
generated at each stage of the chain (Billen et al., 2014
<http://www.sciencedirect.com/science/article/pii/S2211912414000315>, 2015
<http://www.indiaenvironmentportal.org.in/files/file/feeding%20world%202050.pdf>).
It is known that the cascade of N initiated by agricultural losses has huge
effects on groundwater, freshwater and marine ecosystems, air pollution and
terrestrial biodiversity, even far away from the agricultural fields (Sutton
et al., 2011
<http://assets.cambridge.org/97811070/06126/copyright/9781107006126_copyright_info.pdf>
).
The idea is to look at our ability to feed the global population with or
without inter-regional trade exchanges by varying the human diet and the
intensity of N fertiliser use and of animal husbandry. Keeping unchanged
the current cropland areas and the basic performance of cropping and
livestock systems in each region, we explored the capacity to feed the
world and the relative environmental impact according to a very large
number of combinations of three critical drivers of the food system.
The first driver we acted on is human diet, more specifically the total
amount of protein consumed, and the share of animal protein in this total.
Both vary greatly at present, from 3.7 kg proteinN/capita/yr (the minimum
subsistence figure) with 26% animal protein in Africa, to 6.5 kgN/capita/yr
with 65% animal protein in Europe and North America. Between these two
extremes, hunger in the former, excess food intake in the latter, there is
room for adjustment.
The second driver is regional livestock production. When grazing
semi-natural grassland, livestock provide an efficient way of converting
inedible resources into high-value food. We did not change agro-pastoralism
activities in our scenarios. However, to meet the meat and milk
requirements of the population beyond what is offered by grazing on
semi-natural grassland, a region can either import these animal products or
develop mixed or landless livestock farming. This requires either importing
or cultivating feed. Such a strategy may also compete with human nutrition.
Finally, the third driver is the degree of intensification of crop
cultivation, more specifically, the rate of fertilisation of cropland. In
each world region, our model can assess the response of crop yield to total
N input to soil as manure, synthetic fertilisers, symbiotic N fixation by
legume crops and atmospheric deposition. N fertilisation is the major
driver of crop production. However, because of the asymptotic shape of the
yield-vs-fertiliser relationship, which expresses the law of diminishing
returns, the higher the rate of N input to the soil is, the greater the N
losses. These losses pollute water resources and the atmosphere (Lassaletta
et al., 2014). We used the ‘N surplus to cropland’ variable, i.e. the
amount of total N applied to cropland soils over the amount exported with
the harvest, as a proxy for environmental pollution.
*The key results*
Varying these three factors independently in each of the 12 world regions,
we constructed several billion scenarios. Among these only a much smaller
number met the needs of the world population in 2050. Analysing the results
showed that feeding the projected 2050 world population would generally
involve higher levels of inter-regional trade and environmental N
contamination than the current levels. However, the scenarios with less
recourse to inter-regional trade produce less N loss to the environment
(see Fig. 1).
Another finding is that if an equitable human diet (in terms of protein
consumption) is to be established globally (the same in all regions of the
world), the fraction of animal protein should not exceed 40% of total
dietary ingestion. For Europe and North America, this means shifting the
current diet, rich in meat and milk, towards something closer to the
Mediterranean diet, in which plant proteins, pulses, vegetables and fruits
occupy a larger share.
With the same approach, we also showed that slightly improving the
agronomical performance in the most deficient regions (namely Maghreb, the
Middle East, Sub-Saharan Africa, and India) up to the point where they
could be self-sufficient at the minimal diet (i.e. 4 kgN/capita/yr
according to WHO recommendations), is particularly important. It would make
it possible not only to (i) feed the world with much less international
trade (hence more food sovereignty), but also (ii) reduce N environmental
contamination most efficiently (Fig. 1).
Taking the projected increase in the global population as an argument to
justify a never-ending quest for increasing agricultural yields in
developed countries where the population has stabilised is therefore
totally incorrect. In contrast, a scenario of extensification of European
agriculture has been proposed by van Grinsven et al.
<http://iopscience.iop.org/1748-9326/10/2/025002> (2015) and shown to be
beneficial both in terms of environmental costs and food supply on the
world market.
Fig. 1 Global food trade versus nitrogen pollution
Thus, promoting self-sufficiency and food sovereignty does not compromise
global food security and environmental quality. On the contrary, it is the
best option for feeding humans and safeguarding the planet. We can think
globally, but eat locally!
*Figure 1 *(legend): *A vast range of scenarios for feeding the world in
2050 (assuming no major change in the area of arable land) are represented
in this diagram according to the amount of international trade required
(horizontal axis) and the resulting environmental N contamination induced
by N losses from cropland (vertical axis).*
* 1. The current situation (as of 2009) is characterised by an intensity of
international trade of about 25 million tons protein N per year and by N
losses from cropland to the environment as high as 100 million tons per
year.*
* 2. With the projected world population and the diet calculated in each
region of the world by economists, feeding the world would require doubling
the intensity of international trade and nearly tripling agricultural
pollution losses.*
* 3. With an equitable diet (the same for all world regions) set at the WHO
health recommendation, many possibilities exist to meet the requirements of
the world population. All scenarios require more international trade and
would produce more pollution than the current situation, but those with the
lowest rate of international trade also produce the least N contamination.*
*4. If an effort is made to improve the agronomic performance of the most
deficient countries (Maghreb, Sub-Saharan Africa and India) up to the
capacity of self-sufficiency at the lowest possible diet, then it is
possible to feed the world at the optimum equitable diet with much lower
trade and N pollution.*
* 5. The scenario of full regional self-sufficiency (no inter-regional
trade) would produce significantly lower N contamination than currently
observed.*