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Nitrogen Workshop 2012
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Nitrogen Workshop 2012
Nitrogen and food security in the European Union from a global perspective Grinsven, H.J.M. vana, Westhoek, H.Ja., Bouwman, A.F. a, Erisman, J.W.b a PBL Netherlands Environmental Assessment Agency, The Hague, The Netherlands b Louis Bolk institute for international advice and research on sustainable agriculture, nutrition and health care, Driebergen, The Netherlands
1. Background & Objectives Future food security is determined by our ability to accommodate agricultural production with the increase of world population and the change to diets richer in protein. Opportunities to increase the agricultural area are limited because of competing claims by biodiversity conservation, energy cultivation and urbanisation. Increasing nitrogen (N) intensity has been a major factor in increasing agricultural productivity per hectare in the past and hence saving land. But as a consequence N pollution from agriculture has become a major problem from the local to the global scale. This compellingly demands for an increase in N efficiency of agricultural production and diets. The common agricultural policy (CAP) has helped Europe to achieve food security and self sufficiency for most commodities. The European Union (EU) Environmental Directives have lead to an increase in nitrogen efficiencies in European agriculture from 1980 onwards. As a consequence, N pollution from agricultural sources has decreased slowly. However, improvements are stagnating and most environmental targets are not within reach.
This paper analyses the role of N in achieving food security and causing environmental impacts, focusing on Europe. It further explores options to maintain European and global food security while minimizing loss of welfare due to environmental damage.
2. Materials & Methods This paper synthesises results from recent global assessments by UNEP, IPCC, OECD and IAASTD summarized in Kok et al. (2008), additional scenario analyses building on these assessments focussing on N and agriculture, the European Nitrogen Assessment (Sutton et al.,
2011) and an analysis of the European protein puzzle (Westhoek et al., 2011).
3. Results & Discussion Global setting In the UN reference scenario the world population will increase from 7 billion in 2011 to 9 billion in 2050. Between 2000 and 2050 total global caloric intake is expected to increase by 65% and the average global consumption of animal products is expected to double (Stehfest et al., 2009). This compelling demand on the global food system will require an increase in the production of cereals in 2050 by about 60%. The share of feed cereal needed for livestock production will remain at one third. The total area of agricultural land is expected to increase between 2000 and 2050 from 47 to 53 million km2 (Vuuren and Faber, 2009) with 65% in use for grassland and 10% for feed crops. Accounting for about 5% of land use in 2050 for energy cultivation (Bouwman et al., 2010), the 60% increase in cereal production has to be delivered mainly by an increase of productivity per hectare. An average annual increase by 1% would suffice but achievement is at risk. Between 1970 and 2010 the annual increase of wheat productivity decreased from values over 3% to just above 1% globally and less than 1% in Europe and the U.S.A (Dixon, 2009).
difference between the lowest and highest mean wheat yield per hectare in member states of the EU27 (Jensen et al., 2011). However, this recurring factor of four is coincidental as the effect of nitrogen on yield is mixed with effects of local growing conditions, improved plant breeding, irrigation, pest control, availability of other nutrients, and overall improvement of farm management. Using various information sources, Erisman et al. (2008) estimated that mineral N-fertilizer is responsible for about 30-50% of global crop yield increases and may feed almost half of the present world population. Nitrogen can clearly save land, however, such estimates should be viewed with some caution. In part they depend on changing insights on potential crop yields in the absence of mineral N fertilizer and options to close the yield gap. Ponti et al. (2012) estimated the average yield gap between organic and conventional arable agriculture at 20%. Offerman and Nieberg (2000) concluded a similar yield gap between organic and conventional dairy farming.
Nitrogen and animal production Meat and dairy consumption in the EU has increased steadily in the past 50 years from 25 kg of protein per capita in 1960 to over 30 kg in 2007. Consumption of meat is twice the world average and consumption of dairy products exceeds the world average by a factor of three (Westhoek et al., 2011). Total protein consumption per capita in Europe exceeds the recommendation by the World Health Organization by 70%. Over consumption of (red) meat increases the risk of intestinal cancers and over consumption of saturated fatty acids from animal products increases risks for cardiovascular health (Westhoek et al., 2011).
Modern industrial livestock farming has increased the efficiency of conversion of animal feed to human food to 2-3 kg feed per kg eggs or poultry meat and to 3-4 kg feed per kg pork (Lesschen et al., 2011). As a result land demand for feed has slowed down, but yet feeding European livestock presently requires 125-140 million ha of land, and an additional 10-14 million ha outside Europe related to import of protein and oil rich feed stuffs. Of the feeding area in the EU about half is grassland and half is (mainly) for feed cereals and silage maize.
Arable land use for food and animal feed are about equal. The average EU diet requires 0.4 ha per capita, 0.3 ha of this is for animal products.
Nitrogen Workshop 2012 Nitrogen and environment Nitrogen loss to the environment is a, partly inevitable, consequence of production and consumption of food and energy. Typically, nitrogen use efficiencies for arable production in Europe average around 40% (Goulding et al., 2008). Protein (or N) conversion efficiencies in livestock production range from 20-50% for poultry products, 15-30% in pork and dairy and 5-13% in beef (Sutton et al., 2011). This implies that consumption of protein in animal production involves a large indirect consumption of proteins in feed, and through that of nitrogen inputs to produce the feed crops, and of the associated N pollution. The total input of reactive N to agriculture in the EU27 in 2000 was nearly 14 Tg, mainly in the form of chemical N fertilizer (Sutton et al., 2011). This input constitutes 75% of the total input of reactive N. About 40% of the total input is emitted to air as NH3, NOX and N2O, while 50% is lost to water. As a result N pollution from agricultural sources has become the dominant cause of coastal eutrophication and depletion of stratospheric ozone, and significantly contributes to air pollution, drinking water pollution, freshwater eutrophication, biodiversity loss and disruption of the greenhouse balance.
Nitrogen and welfare Nitrogen contributes to welfare by increasing agricultural productivity and allowing protein rich diets and for some regions export of agricultural products. The total value of agricultural production (including industrial processing) in 2000 in the EU27 amounted to more than 300 billion euro/yr, of which about 40% (120 billion euro/yr) could be attributed to nitrogen. On the other hand environmental pollution creates a welfare loss. The total damage (or external) cost for the EU related to agricultural emissions of nitrogen was estimated at 25-145 billion euro/yr (Fig. 2; Brink et al., 2011) and appears to be in the same range as the (direct) economical benefits of nitrogen. Damage cost estimates are based on surveys on willingnessto-pay to prevent environmental impacts of nitrogen and need further debate in view of large uncertainties and conceptual issues.
Figure 2. Welfare loss due to environmental damage in the EU27 in 2000 caused by nitrogen emission from agricultural production and energy generation
An insight into diets and agricultural production processes, when combined with external costs, allows the calculation of the N footprint of individual consumption (Leach et al., 2011).
The cost of N damage and N footprints are novel ways to communicate N pollution to a larger audience and help to find new optimums for N management in agriculture and the food system at large.
Future nitrogen use Because of the many uncertain drivers and factors, global use of N fertilizer in 2050 in recent scenario studies (Bouwman et al., 2009, 2011; Erisman et al., 2008) is also very uncertain.
Relative to 2000, it ranges between a doubling and a small decrease. In contrast, for Europe these scenarios show a consolidation in the use of N fertilizer and a small increase in manure production, together with a modest increase in nutrient use efficiencies. A worst case scenario for global food security and N pollution would be a shift to global animal protein rich diets combined with high ambitions for land and N demanding energy cultivation. This could result in the skyrocketing of global food and fertilizer prices. An alarming recent observation is that N fertilizer use has increased by more that 25% between 2000 and 2009, and now is at the level that was predicted by FAO for 2030 (Bruinsma, 2003). Equally alarming are the sharp increases and strong variations in food and fertilizer prices since 2008.
Nitrogen challenges and options for Europe Challenges to maintain European and global food security while minimizing loss of welfare due to N pollution, are increasing nutrient use efficiency, consolidating agricultural land area and changing diets. Reducing food waste, amounting to 30% globally and in Europe, appears to be an easy and no regret first priority but waste is deeply embedded in the food chain and in consumer behaviour (Gustavsson et al. 2011). Complicating factors not yet included in most scenarios are the effects of climate change on agricultural production, and particularly for Europe, stricter demands on animal welfare, human health risks and use of antibiotics, which will likely decrease feed conversion efficiencies (Westhoek et al., 2012).
A great opportunity for the EU is smart development of agriculture in the new central and eastern member states or in the western states of the FSU. For example Romania and Bulgaria hold about 20% of the agricultural land in the EU27, while productivity and nitrogen intensity and environmental cost are still low (Jensen et al., 2011). A well integrated EU food and N policy would stimulate a transition from economical (or private) optimal N fertilizer rates to economical and environmental (or societal) optimal rates (Brink et al. 2011; Good and Beatty, 2011). Using N damage costs from Brink et al. (2011) this optimal societal nitrogen fertilization rate for winter wheat in northwest Europe, would be 30-90 kilogram/ha (median 55 kilogram/ha; 30%) lower than current recommended rates. The concurrent reduction in cereal yield according to conventional nitrogen response curves would be 1-2 tonnes per hectare and compromise food security. However, in view of the recent findings by Ponti et al.
(2012), this yield loss due to lower inputs of mineral nitrogen could be compensated to a large extent by adapting nutrient conservation and cycling practices of organic farming.