Algal bloom, driven by phosphorus. Image via Wikipedia
The lights will probably go out at LOVESalem HQ by mid-century, but there's plenty of folks in Salem who would like to be doing all the usual stuff for decades past that, especially things like, you know, eating.
Those people might want to start planning ahead now for the investment opportunity of the century: peak phosphorus.
Peak phosphorus is going to make dealing with peak oil seem like child's play. We can talk about oil as an "addiction" because it truly is something that we can live without, like cigarettes. But there's no doing without phosphorus, period.
Salem is the county seat of Oregon's No. 1 Ag producing county. Wonder if there's anyone in City or County government thinking about how we're going to grow crops without imported phosphorus (when the world price skyrockets and we can't afford to buy it).
Scientific American Magazine - June 3, 2009
Phosphorus Famine: The Threat to Our Food Supply
. . . Our planet is also a spaceship: it has an essentially fixed total amount of each element. In the natural cycle, weathering releases phosphorus from rocks into soil. Taken up by plants, it enters the food chain and makes its way through every living being. Phosphorus—usually in the form of the phosphate ion PO43-—is an irreplaceable ingredient of life. It forms the backbone of DNA and of cellular membranes, and it is the crucial component in the molecule adenosine triphosphate, or ATP—the cell’s main form of energy storage. An average human body contains about 650 grams of phosphorus, most of it in our bones. . . .
Harvesting breaks up the cycle because it removes phosphorus from the land. In prescientific agriculture, when human and animal waste served as fertilizers, nutrients went back into the soil at roughly the rate they had been withdrawn. But our modern society separates food production and consumption, which limits our ability to return nutrients to the land. Instead we use them once and then flush them away.
Agriculture also accelerates land erosion—because plowing and tilling disturb and expose the soil—so more phosphorus drains away with runoff. And flood control contributes to disrupting the natural phosphorus cycle. Typically river floods would redistribute phosphorus-rich sediment to lower lands where it is again available for ecosystems. Instead dams trap sediment, or levees confine it to the river until it washes out to sea. . . .
The standard approaches to conservation apply to phosphorus as well: reduce, recycle and reuse. We can reduce fertilizer usage through more efficient agricultural practices such as terracing and no-till farming to diminish erosion [see “No-Till: The Quiet Revolution,” by David R. Huggins and John P. Reganold; Scientific American, July 2008]. The inedible biomass harvested with crops, such as stalks and stems, should be returned to the soil with its phosphorus, as should animal waste (including bones) from meat and dairy production, less than half of which is now used as fertilizer.
We will also have to treat our wastewater to recover phosphorus from solid waste. This task is difficult because residual biosolids are contaminated with many pollutants, especially heavy metals such as lead and cadmium, which leach from old pipes. Making agriculture sustainable over the long term begins with renewing our efforts to phase out toxic metals from our plumbing.
Half the phosphorus we excrete is in our urine, from which it would be relatively easy to recover. And separating solid and liquid human waste—which can be done in treatment plants or at the source, using specialized toilets—would have an added advantage. Urine is also rich in nitrogen, so recycling it could offset some of the nitrogen that is currently extracted from the atmosphere, at great cost in energy.
Fertilizer runoff and wastewater discharge contribute to eutrophication, uncontrolled blooms of cyanobacteria in lakes and oceans, often large enough to be seen from orbit. Cyanobacteria (also known as blue-green algae) feed on nitrogen and phosphorus from fertilizers. . . . Cyanobacteria living in freshwater can extract nitrogen from the air, so limiting phosphorus runoff is essential, as was confirmed in 2008 by a 37-year-long study in which researchers deliberately added nutrients to a Canadian lake. “There’s not a single case in the world where anyone has shown that you can reduce eutrophication by controlling nitrogen alone,” says lead author David Schindler of the University of Alberta in Edmonton. Cyanobacteria living in seawater seem unable to take in atmospheric nitrogen but may get enough phosphorus from existing sediment, other researchers point out, urging controls on nitrogen as well.
In the comments at The Oil Drum, Bart Anderson of The Energy Bulletin notes:
Phosphorous is different . . . . It's a less tractable problem than even energy, for which there are multiple sources and many ways to reduce usage.
Once easily mined phosophorous ore is gone, there is NO ALTERNATIVE. Yes, we can recycle to some extent, but there are always losses and there will be little new phosphorus to bring into the system.
Plants need N-P-K, and one of those nutrients is usually the limiting factor for an ecosystem.
Nitrogen can be produced from the atmosphere, but not phosphorus.
So, if the population is at a level to require added nutrients, which is likely even if populations are reduced, we will need phosphorus.
In the 19th century, with a much lower populations, Europe experienced a shortage of nutrients.
I'm thinking that phosphorus is probably the limiting factor for human populations.
Articles on phosphorus: