Environmental Engineering Reference
In-Depth Information
BOX 8.2
WILLWE RUN OUT OF PHOSPHORUS?
The supply of P available for human use
is limited, P is essential to grow crops and
feed people, and there are no known substi-
tutes. Increasingly, people are aware of the
issue of peak oil, typically defined as the
point in time when the maximum rate of
petroleum extraction is reached, after which
extraction will decline. Yet, known substi-
tutes for fossil fuels are many, including
solar energy, biofuels, and wind energy.
And unlike nitrogen, which can be fixed
from vast atmospheric reservoirs (see
Chapter 7), we cannot manufacture P.
Among these major constituents upon
which human life depends, it is only P for
which there are no known substitutes and a
limited supply.
At the same time, consumption of P is
increasing at about 3% annually, an increase
that is expected to expand (
Cordell et al.
2009
). More P will be needed to meet
increased demands for agricultural produc-
tion, which will have to double by 2050 to
meet demands posed by a growing human
population and increased demand for meat
in rapidly developing countries. Add to this
expanding biofuel enterprises that also raise
P demand. Approximately 10% of fertilizer
use in the United States is applied to corn
used to produce ethanol (Childers et al.
2011). Prices of P rock are beginning to fluc-
tuate wildly in response to changes in our
estimates of how much we have, global pol-
itics, and so on.
These facts increasingly bring us to con-
sider the issue of peak P and to wonder
when limited P supplies will become a criti-
cal issue in food supply and how this will
affect global politics. Working with the 2009
United States Geological Survey (USGS) P
reserve estimates, sustainability scientist
Dana Cordell and colleagues used a
Hubbert, “peak oil”
type analysis to fore-
cast a date for “peak P” production of
approximately 2030 (
Cordell et al. 2009
).
Currently, perspectives on emerging P scar-
city are in flux following a revision of the
global P reserve estimate by economic geol-
ogist Steven Van Kauwenbergh of the
International Fertilizer Development Center
(IFDC; Van Kauwenbergh 2010): The new
figure is nearly 10 times higher than the
2009 USGS value and this new value has
now been adopted by USGS. Importantly,
these “new” reserves, which were identified
largely based on Van Kauwenbergh's inclu-
sion of some overlooked 25-year-old
reports, lie entirely in one country: Morocco
(and its disputed territory of Western
Sahara).
To the extent that the IFDC estimates are
accurate, the urgency of geological scarcity
issues is perhaps pushed back by several
decades, according to reanalysis by Cordell
and colleagues. However, politics may
trump geology in this case. The geographic
distribution of P reserves is hyper-concen-
trated—five countries control 90% of esti-
mated reserves, with Morocco obviously in
the driver's seat. Since major regions of the
world have diminishing (USA), few (India),
or no (northern Europe) P reserves of their
own, without diversification of fertilizer
supplies (via internal recycling) many of the
world's
food
producers will
become
completely dependent
on
trade with
Morocco.
