chlamor
12-04-2007, 09:50 AM
Peak phosphorus
by Patrick Déry and Bart Anderson
Peak oil has made us aware that many of the resources on which civilization depends are limited.
M. King Hubbert, a geophysicist for Shell Oil, found that oil production over time followed a curve that was roughly bell-shaped. He correctly predicted that oil production in the lower 48 states would peak in 1970. Other analysts following Hubbert's methods are predicting a peak in oil production early this century.
The depletion analysis pioneered by Hubbert can be applied to other non-renewable resources. Analysts have looked at peak production for resouces such as natural gas, coal and uranium.
In this paper, Patrick Déry applies Hubbert's methods to a very special non-renewable resource - phosphorus - a nutrient essential for agriculture.
In the literature, estimates before we "run out" of phosphorus range from 50 to 130 years. This date is conveniently far enough in the future so that immediate action does not seem necessary. However, as we know from peak oil analysis, trouble begins not when we "run out" of a resource, but when production peaks. From that point onward, the resource becomes more difficult to extract and more expensive.
Physicist Déry applied the technique of Hubbert Linearization to data available from the United States Geological Survey (USGS)[1] to phosphorus production in the following:
* The small Pacific island nation of Nauru, a former phosphate exporter.
* The United States, a major phosphate producer.
* The world.
He tested Hubbert Linearization first on data from Nauru to see whether he could have predicted the year of its peak phosphate production in 1973. Satisfied with the results, he applied the method to United States and the world. He estimates that U.S. peak phosphorus occurred in 1988 and for the world in 1989.
Phosphorus - its role and nature
Phosphorus (chemical symbol P) is an element necessary for life. Because phosphorus is highly reactive, it does not naturally occur as a free element, but is instead bound up in phosphates. Phosphates typically occur in inorganic rocks.
As farmers and gardeners know, phosphorus is one of the three major nutrients required for plant growth: nitrogen (N), phosphorus (P) and potassium (K). Fertilizers are labelled for the amount of N-P-K they contain (for example 10-10-10).
Most phosphorus is obtained from mining phosphate rock. Crude phosphate is now used in organic farming, whereas chemically treated forms such as superphosphate, triple superphosphate, or ammonium phosphates are used in non-organic farming.
Philip H. Abelson writes in Science:
The current major use of phosphate is in fertilizers. Growing crops remove it and other nutrients from the soil... Most of the world's farms do not have or do not receive adequate amounts of phosphate. Feeding the world's increasing population will accelerate the rate of depletion of phosphate reserves.
and
...resources are limited, and phosphate is being dissipated. Future generations ultimately will face problems in obtaining enough to exist.
It is sobering to note that phosphorus is often a limiting nutrient in natural ecosystems. That is, the supply of available phosphorus limits the size of the population possible in those ecosystems.
More information:
* Understanding Phosphorus and its Use in Agriculture from the European Fertilizer Manufacturers Association.
* Phosphate Primer by Florida Institute of Phosphate Research.
Prospect of a Phosphorus Peak
In his frightening book Eating Fossil Fuels [3], Dale Allen Pfeiffer shows that conventional agriculture is as oil-addicted as the rest of society. A decline in oil production raises questions about how we will feed ourselves.
In the same way, agriculture is addicted to mined phosphates and would be threatened by a peak in phosphate production. As the U.S. Geological Survey (USGS) wrote in summary on phosphates (PDF):
There are no substitutes for phosphorus in agriculture.
Fortunately, phosphorus - unlike oil - can be recycled. Responses to a phosphorus peak include re-creating a cycle of nutrients, for example, returning animal (including human) manure to cultivated soil as Asian people have done in the not-so-distant past [4].
Hubbert Linearization
Tools that have been used for analyzing peak oil can be applied to phosphate production. As we will see, phosphorus production follows a more-or-less bell-shaped (parabolic) curve, just as oil production does.
Hubbert's parabolic curve is based on a differential equation explained by Stuart Staniford:
The idea behind the equation is that early on, the oil industry grows exponentially - the annual increase in production is proportional to the total amount of knowledge of resources, oil field equipment, and skilled personnel, all of which are proportional to the size of the industry. ...
Later, however, the system begins to run into the finiteness of the resource - it gets harder and harder to get the last oil from the bottom of the depressurized fields, two miles down in the ocean, etc, etc.
To estimate future production and total production, some analysists have turned to the technique of Hubbert Linearization (H-L).
Hubbert Linearization was first developed by geologist Kenneth Deffeyes, an associate of M. King Hubbert. The technique has been discussed by analysts such as Stuart Staniford, Jeffrey J. Brown and Robert Rapier at The Oil Drum. The term Hubbert Linearization was coined by Stuart Staniford.
In Hubert Linearization, the production data from the bell-shaped Hubbert curve is plotted as a line. On the graph:
the y-axis (vertical) is P/Q where
P = annual production and
Q = total production to date
the x-axis (horizontal) is Q (total production to date).
By extending the line in the graph, one can estimate Ultimate Recoverable Reserves (URR) for the region (Qt).
This paper purposely minimizes the math so as to reach a wide audience; however, much more detail on H-L is available online. For example:
Hubbert Linearization (Wikipedia)
In Defense of the Hubbert Linearization Method
Another Way of Looking at CERA by Stuart Staniford
When Does Hubbert Linearization Work? by Stuart Staniford
Predicting the Past: The Hubbert Linearization by Robert Rapier (H-L skeptic)
Applying Hubbert Linearization to Phosphates
For the purposes of this paper, Déry looked at data for commercial phosphate (26-34% of P2O5). Other reserves of rock phosphate with lower concentrations of P2O5 do exist, but, just as with tar sand for oil production, they are more costly to exploit - economically, energetically and environmentally.
Using data from United States Geological Survey (rock phosphate production historical data series), Déry did a Hubbert Linearization for United States and for world rock phosphate production.
Results were stunning. The theoretical logistic curve fits almost perfectly with the real data curve. Déry found that we have already passed the phosphate peak for the United States (1988) and for the world (1989).
Nauru
However those results seemed too perfect, so Déry tested the method on an almost depleted region of rock phosphate production, a case similar to that of United Stated for oil. A small island in the South Pacific called Nauru appeared to be an ideal case. The Nauru Island is 21 km² with only one economic resource (besides being a fiscal paradise!): rock phosphate. This resource has been almost entirely depleted since 2005.
According to the CIA World Factbook:
...intensive phosphate mining during the past 90 years - mainly by a UK, Australia, and NZ consortium - has left the central 90% of Nauru a wasteland and threatens limited remaining land resources.
<snip>
http://www.energybulletin.net/33164.html
by Patrick Déry and Bart Anderson
Peak oil has made us aware that many of the resources on which civilization depends are limited.
M. King Hubbert, a geophysicist for Shell Oil, found that oil production over time followed a curve that was roughly bell-shaped. He correctly predicted that oil production in the lower 48 states would peak in 1970. Other analysts following Hubbert's methods are predicting a peak in oil production early this century.
The depletion analysis pioneered by Hubbert can be applied to other non-renewable resources. Analysts have looked at peak production for resouces such as natural gas, coal and uranium.
In this paper, Patrick Déry applies Hubbert's methods to a very special non-renewable resource - phosphorus - a nutrient essential for agriculture.
In the literature, estimates before we "run out" of phosphorus range from 50 to 130 years. This date is conveniently far enough in the future so that immediate action does not seem necessary. However, as we know from peak oil analysis, trouble begins not when we "run out" of a resource, but when production peaks. From that point onward, the resource becomes more difficult to extract and more expensive.
Physicist Déry applied the technique of Hubbert Linearization to data available from the United States Geological Survey (USGS)[1] to phosphorus production in the following:
* The small Pacific island nation of Nauru, a former phosphate exporter.
* The United States, a major phosphate producer.
* The world.
He tested Hubbert Linearization first on data from Nauru to see whether he could have predicted the year of its peak phosphate production in 1973. Satisfied with the results, he applied the method to United States and the world. He estimates that U.S. peak phosphorus occurred in 1988 and for the world in 1989.
Phosphorus - its role and nature
Phosphorus (chemical symbol P) is an element necessary for life. Because phosphorus is highly reactive, it does not naturally occur as a free element, but is instead bound up in phosphates. Phosphates typically occur in inorganic rocks.
As farmers and gardeners know, phosphorus is one of the three major nutrients required for plant growth: nitrogen (N), phosphorus (P) and potassium (K). Fertilizers are labelled for the amount of N-P-K they contain (for example 10-10-10).
Most phosphorus is obtained from mining phosphate rock. Crude phosphate is now used in organic farming, whereas chemically treated forms such as superphosphate, triple superphosphate, or ammonium phosphates are used in non-organic farming.
Philip H. Abelson writes in Science:
The current major use of phosphate is in fertilizers. Growing crops remove it and other nutrients from the soil... Most of the world's farms do not have or do not receive adequate amounts of phosphate. Feeding the world's increasing population will accelerate the rate of depletion of phosphate reserves.
and
...resources are limited, and phosphate is being dissipated. Future generations ultimately will face problems in obtaining enough to exist.
It is sobering to note that phosphorus is often a limiting nutrient in natural ecosystems. That is, the supply of available phosphorus limits the size of the population possible in those ecosystems.
More information:
* Understanding Phosphorus and its Use in Agriculture from the European Fertilizer Manufacturers Association.
* Phosphate Primer by Florida Institute of Phosphate Research.
Prospect of a Phosphorus Peak
In his frightening book Eating Fossil Fuels [3], Dale Allen Pfeiffer shows that conventional agriculture is as oil-addicted as the rest of society. A decline in oil production raises questions about how we will feed ourselves.
In the same way, agriculture is addicted to mined phosphates and would be threatened by a peak in phosphate production. As the U.S. Geological Survey (USGS) wrote in summary on phosphates (PDF):
There are no substitutes for phosphorus in agriculture.
Fortunately, phosphorus - unlike oil - can be recycled. Responses to a phosphorus peak include re-creating a cycle of nutrients, for example, returning animal (including human) manure to cultivated soil as Asian people have done in the not-so-distant past [4].
Hubbert Linearization
Tools that have been used for analyzing peak oil can be applied to phosphate production. As we will see, phosphorus production follows a more-or-less bell-shaped (parabolic) curve, just as oil production does.
Hubbert's parabolic curve is based on a differential equation explained by Stuart Staniford:
The idea behind the equation is that early on, the oil industry grows exponentially - the annual increase in production is proportional to the total amount of knowledge of resources, oil field equipment, and skilled personnel, all of which are proportional to the size of the industry. ...
Later, however, the system begins to run into the finiteness of the resource - it gets harder and harder to get the last oil from the bottom of the depressurized fields, two miles down in the ocean, etc, etc.
To estimate future production and total production, some analysists have turned to the technique of Hubbert Linearization (H-L).
Hubbert Linearization was first developed by geologist Kenneth Deffeyes, an associate of M. King Hubbert. The technique has been discussed by analysts such as Stuart Staniford, Jeffrey J. Brown and Robert Rapier at The Oil Drum. The term Hubbert Linearization was coined by Stuart Staniford.
In Hubert Linearization, the production data from the bell-shaped Hubbert curve is plotted as a line. On the graph:
the y-axis (vertical) is P/Q where
P = annual production and
Q = total production to date
the x-axis (horizontal) is Q (total production to date).
By extending the line in the graph, one can estimate Ultimate Recoverable Reserves (URR) for the region (Qt).
This paper purposely minimizes the math so as to reach a wide audience; however, much more detail on H-L is available online. For example:
Hubbert Linearization (Wikipedia)
In Defense of the Hubbert Linearization Method
Another Way of Looking at CERA by Stuart Staniford
When Does Hubbert Linearization Work? by Stuart Staniford
Predicting the Past: The Hubbert Linearization by Robert Rapier (H-L skeptic)
Applying Hubbert Linearization to Phosphates
For the purposes of this paper, Déry looked at data for commercial phosphate (26-34% of P2O5). Other reserves of rock phosphate with lower concentrations of P2O5 do exist, but, just as with tar sand for oil production, they are more costly to exploit - economically, energetically and environmentally.
Using data from United States Geological Survey (rock phosphate production historical data series), Déry did a Hubbert Linearization for United States and for world rock phosphate production.
Results were stunning. The theoretical logistic curve fits almost perfectly with the real data curve. Déry found that we have already passed the phosphate peak for the United States (1988) and for the world (1989).
Nauru
However those results seemed too perfect, so Déry tested the method on an almost depleted region of rock phosphate production, a case similar to that of United Stated for oil. A small island in the South Pacific called Nauru appeared to be an ideal case. The Nauru Island is 21 km² with only one economic resource (besides being a fiscal paradise!): rock phosphate. This resource has been almost entirely depleted since 2005.
According to the CIA World Factbook:
...intensive phosphate mining during the past 90 years - mainly by a UK, Australia, and NZ consortium - has left the central 90% of Nauru a wasteland and threatens limited remaining land resources.
<snip>
http://www.energybulletin.net/33164.html