Peak Phosphorus

Below is an excerpt from page 176 of Princeton professor Kenneth S. Deffeyes from his book “Beyond Oil, the view from Hubbert’s Peak” (2005):

Phosphate (PO4+++) is mined commercially from sedimentary rocks containing the mineral apatite, a form of calcium phosphate. The biggest phosphate producer, with the biggest remaining reserves, is Morocco. By now, you know the message: Major deposits turn out to be concentrated in odd corners of the world. The United States is in second place, with large phosphate mines in Florida and Idaho.

Why worry about phosphate supplies? Won’t we find a substitute by then? Phosphate is the backbone of DNA and RNA. The universal energy “currency” within cells is based on the conversion of ATP to ADP, adenosine triphosphate and adenosine diphosphate. Our teeth and bones are made of the mineral apatite. Substitute that. The next element below phosphorous in the chemical periodic table is arsenic. Not a promising place to start.

Phosphorus is essential to agriculture, increasing yields up to 50%, with 80% of phosphorus used in fertilizers to grow crops, and much of the rest in animal feed.

No other element can substitute and it can’t be synthesized.

Even if there’s lots of sun, water, and other elements, lack of phosphorus limits a plant or animal from using all of the other abundant resources. Therefore, it is no exaggeration to say that phosphorus is the most important limiting nutrient.

Recycling most of the phosphorus isn’t possible

Modern agriculture is practiced as if we had unlimited supplies.   Every truck load of food uses up phosphorus that will never return.

But it’s not all that easy to recycle in urban environments, which get food from far away agricultural regions.  If you do go to the trouble to extract phosphorus from urine and feces, how do you send it all back to all the places the imported food came from?  What little gets recycled now is sewage sludge dumped on nearby farms, where it accumulates, potentially over saturating the soil.  Recycling would also keep phosphorus from washing into rivers, lakes and oceans, where it leads to eutrophication.

But it’s too expensive to recycle and return the phosphorus to where it came from — that uses far too much energy, and we are on the cusp of energy shortages and oil shocks.  Nor can we mine more — that’s even more energy intensive, and often too expensive to extract even in politically stable nations.

If it wasn’t clear to people that this was a mineral we were dependent on, it became pretty clear in 2008, when global phosphorus prices went up 800%.

How much phosphorus is left and what other risks are there?

Recent estimates of peak phosphorus are 2027 (Mohr) and 2033 (Craswell), but you can find dozens of estimates, The most optimistic estimates lead to phosphorus running out within 200 years (Cordell).

Morocco has 85% of the remaining reserves (mainly in the Western Sahara). Morocco is potentially unstable, as are these five nations with another five percent of reserves: China, Algeria, Syria, Jordan, and South Africa.

Also vulnerable are the nations that need to import nearly all of their phosphorus, such as Europe, Brazil, and India. The United States has about 25 years of phosphate reserves left.

Dary, Patrick, Phosphorus: is a paradigm shift required (Bardi 2014).

We can’t live without phosphorus: agriculture depends on it to enrich their soils. Phosphorus is second only to nitrogen as the most limiting element for plant growth.  Crop yields on 40% of the world’s arable land is limited by phosphorus availability (30). Nitrogen can be extracted from the air, but phosphorus can’t, it only exists in Earth’s crust, mainly phosphate rock converted to a soluble form for fertilizer, after which much of it is lost, 20% absorbed by plants the first years, some of it disappears in runoff, or locked in the soil in chemical forms plants can’t access.  Much of it is exported within food crops.

Production in the U.S. has been declining 4 to 5% a year since about 1980.

And like all minerals, if phosphorus ever gets very expensive, rising prices will cause a reduction in demand, and that eventually stops rising production.  Industry won’t extract resources so expensive they’re impossible to sell.  Consequently, there’s a limit to the low-grade resources the industry can exploit. Economists assume that technology will always come to the rescue, lower costs of extraction and restoring both demand and industry profits. But this is a leap of faith: technology has monetary and energy costs so there are limits to what it can do. So the phosphate rock production won’t end due to a lack of rock.  But since it depends on the energy derived from oil to extract, transform, and transport, when oil declines, it will too.


Bardi, Ugo. 2014. Extracted: How the Quest for Mineral Wealth Is Plundering the Planet. Chelsea Green Publishing.

Cho, Renee. 2013. Phosphorus: Essential to Life—Are We Running Out?

Cordell, D. et al. 2013. Phosphorus vulnerability: A qualitative framework for assessing the vulnerability of national and regional food systems to the multi-dimensional stressors of phosphorus scarcity. Global Environmental Change,  DOI: 10.1016/j.gloenvcha.2013.11.005

Craswell, E.T. et al. 2010. Peak phosphorus—Implications for soil productivity and global food security. Paper read at the 19th World Congress of Soil Science, Soil Solutions for a Changing World, August 1-6, Brisbane, Australia.

Huva, A. 2013.  Much Ado about Phosphorus.

Blodget, H. 4 Dec 2012. Henry Blodget. A Genius Investor Thinks Billions Of People Are Going To Starve To Death — Here’s Why. Business Insider.

Elser, J. 20 2010.  Peak Phosphorus. It’s an essential, if underappreciated component of our daily lives, and a key link in the global food chain. And it’s running out. Foreign Policy.

Faludi, J. 25 Dec 2007.  Your Stuff: If It Isn’t Grown, It Must Be Mined. WorldChanging

Mohr, S, et al. 2013. Projections of Future Phosphorus Production. Philica.

Vaccari, D. A. June 2009. Phosphorus: A Looming Crisis. This underappreciated resource–a key part of fertilizers–is still decades from running out. But we must act now to conserve it, or future agriculture will collapse. Scientific American.

Walan, P. et al. 2014. Phosphate rock production and depletion: Regional disaggregated modeling and global implications. Resources, Conservation and Recycling, 93: 178-187.

Woods, H. 3 Apr 2008. World’s phosphorus situation scares some scientists. The Coloradan.



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