30 4.3 Future scenarios Different scenarios can be described by combining the figures for the global population and wealth growth and the additional growth due to biofuel production as mentioned in the previous section. The following four scenarios are evaluated concerning the sufficiency of current phosphate resources: Scenario 1 (zero growth): zero growth of global food consumption and biofuel production. Scenario 2 (low growth): 1.5% annual growth of global food consumption until 2050 and 12.3% annual growth of biofuel production until 2030. Scenario 3 (intermediate growth): 2.7% annual growth of global food consumption until 2050 and 12.3% annual growth of biofuel production until 2030. Scenario 4 (high growth): 4.4% annual growth of global food consumption until 2050 and 15.7% annual growth of biofuel production until 2030. The sufficiency of the global phosphate reserve base under different scenarios is plotted for the period 2008 – 2100 (Figure 4.1). It is clear that the different scenarios result in very different predictions for the time the current phosphate reserves will be exhausted, which ranges between 2042 and 2098 (Table 4.2). These estimates fall within predicted sufficiency of the phosphate reserves of 50 – 100 years as calculated in earlier studies (Steen, 1998; Smil, 2000; Gunther, 2005). The total reserve base would however last for much longer and predictions range between 2072 (high growth) and well beyond 2200 (zero growth). In view of the slight growth of the world phosphate consumption in the past two decades, it is more likely that a scenario of low to moderate global growth will be realised (scenarios 1 or 2). Nevertheless, the combined production of food and biofuels under these scenarios will cause the global reserve base to be depleted roughly somewhere between 2100 and 2150 (Table 2). The increasing demand for phosphate will spur exploration efforts for new reserves, which will add to our future reserve base. Although the size of the future reserve base is not known, it seems safe to state that at prices of 50 - 100 US$ per ton the reserve base would roughly double (see Chapter 2). If the future increase of the reserve base were taken into account, our global phosphate reserves would last well into the next century and probably well beyond. Previous projections by other authors (e.g. Steen, 1998; Smil, 2000; Gunther, 2005) often only take the current reserves into account, which is a gross underestimate of our global minable phosphate resources. Pagina 39

Pagina 41

Heeft u een nieuwsbrief, novia facts of ewhitepapers? Gebruik Online Touch: whitepaper converteren naar een online publicatie.

458 Lees publicatie 159Home