This discrepancy is probably the result of the improved standard of living and higher meat consumption, particularly in the western world. Since the production of a meat-based diet uses about 3 times more phosphate than the production of a vegetarian diet (e.g. Cordell et al., 2009), phosphate consumption may increase at a substantially faster rate than the population if countries such as India, China and Brazil continue to develop to North American or European food consumption standards in the future. The use of phytase in animal fodder may make the uptake of phosphate by domestic animals more effective. 29 Consumption for biofuel production When we take into account the increasing amount of phosphate required for the production of biofuels such as bio-ethanol and bio-diesel, the IFA growth figures given above might be an underestimate. Crops grown for the production of biofuels currently account for 2.4% of the world fertiliser consumption (IFA, 2008). This means that the consumption of phosphate for biofuel production in 2008 required some 3 - 4 Mt of phosphate rock. The biofuel produced globally in 2008 represents an energy value of about 1 eJ (exajoule). Depending on land availability and production capacity, the energy derived from biofuels is estimated to have increased in 2050 to anywhere between a low of 160 and a high of 450 exajoules (Table 3.3). This would imply a growth of the phosphate consumption of 12.3% to 15.7% under low and high biofuel growth scenarios respectively. Biofuel production from organic waste and residues are not included here as they do not require additional phosphate i.e. this growth is included in global consumption figures. These estimates also exclude the production of biomaterials such as plastics from bio-ethanol and bio-diesel. Serious competition between phosphate consumption for biofuel and food production will however result in political measures to restrain the production of biofuels from both existing agricultural land as well as marginal lands. Therefore, the additional role of biofuel production remains difficult to predict. Although it is clear that the amount of phosphate used for biofuel production will grow rapidly in the next two decades, it is difficult to determine what growth rates can be expected after 2030 - 2040. In the following section, zero growth for the period after 2030 is assumed. A shift from land-based biofuel crops to the farming of marine algae for biofuel production will eliminate the competition with food production, but will probably not substantially change the phosphate requirements. Sometimes it is argued that because algae use P more efficiently, the phosphate requirements will decrease. Biomass type Energy crop farming (current agricultural land) Energy crop farming (marginal land) Marine energy crops Totals Low scenario 100 60 ? 160 High scenario 300 150 ? 450 Table 4.1: Future energy production from selected biomass types in 2050 (all in exajoules = 1018 Joules; WWI, 2006). The data represents the more conservative estimate by WWI, and excludes the production of biofuels for biomaterials and biofuel production from waste and residues (e.g. plastics). Pagina 38

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