This was sent by Hakan Jönsson (Sweden) to some people from working group 5. He has allowed me to copy it here:

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From: Håkan Jönsson
Sent: Friday, December 09, 2011 6:33 PM
Subject: RE: [Wg5] SuSanA WG5 fact sheet - FINAL DRAFT

Dear Rob,
I still would be a lot happier, if the paragraph about the reserve life time did not further cement the notion that this is how long the reserve will last. This is why I for pedagogic reasons earlier proposed the wording:

The prospects for potassium (or potash) are comparable with phosphorus. The size of the currently known reserves corresponds for potassium and phosphorus to 250-300 and 350-400 years, respectively, of production at the present rate. However, those estimates have to be taken with care as they neither reflect other factors like population growth, continuously increasing extraction rates and rising costs for energy-intensive mining nor the potential discovery of new deposits.

If the life time of the reserve really meant how long the reserve will last, how come we have not run out of zinc, as we over the last 16 years (1995-2010) have used 146,920,000 tons, which is more than the total amount of zinc in the zinc reserve 1995 (140,000,000 tons)? The same behaviour can we see for the reserves of oil. In 1974 the oil reserve had a life time of about 40 years, year 2000 it was also 40 years and at the end of 2009 it was 48 years if we exclude the proven reserves in the Canadian oil sands. If we include them it was 54 years!

Therefore, I personally think that there is no solid evidence that there is any risk at all of a peak-P or a peak-K over the coming centuries. Over the last 16 years, the production of rock phosphorus has increased by 28% (from 1,37E+08 to 1,76E+08 metric tons), while the known economic reserves of rock phosphorus have increased by 491% (from 1,10E+10 to 6,50E+10 metric tons). Still in the calculations by Arno, only the increase in production is included and no increase in the reserve. There is no projection included that we will find, or by new technology develop, any new reserve of phosphorus over the coming centuries. Is it really probable that the increase in reserves, which has occurred both for zinc, oil and phosphorus, for phosphorus totally stopped at the end of year 2010? That we during the coming 200 years will not discover any more economically exploitable resource? I believe that during the coming 200 years we will discover new reserves and in addition develop technology to economically exploit the “Large phosphate resources …identified on the continental shelves and on seamounts in the Atlantic Ocean and the Pacific Ocean” (USGS, 2009), especially as these 2009 seemed to be only marginally subeconomical “High phosphate rock prices have renewed interest in exploiting offshore resources of Mexico and Namibia.”(ibid).

It might also be interesting to note that the life time of the phosphate rock reserve 1995 was 80 years, while it 2010 was 369 years, which I also think shows that it is not that easy that the reserve steadily decreases. Instead it seems that it often stays about constant and for some elements, e.g. phosphorus it increases.

Thus, I really think we, in our work towards sustainability, should focus on the nutrients that give the largest added value to the farmer here and now. On some soils it is phosphorus, but I am quite convinced that in most locations it is the nitrogen, while on some soils it is the potassium that can boost the crop the most.

Sustainable regards,
Håkan

Dear all,

I am following the discussion on the peak of phosphorous with great interest and I would like to bring your attention to an article found in the SCOPE Newsletter December 2011 page 4:

"Phosphorus resources and global food supply
Vaccari and Strigul assess to what extent it is possible to estimate phosphate resources from known data and trends such as resource price, ore grade and discovery rates, using Hubbert curve extrapolation.
They note that the Hubbert curve, which predicted US oil production, might not be applicable to global resources, nor for materials for which there is no possible substitute (such as phosphorus), and that Hubbert indicated that production might pass through one or more peaks. They conclude that the bell-shaped curve is unlikely to provide robust predictions of “peak” phosphorus production, given that the ultimately recoverable resource (URR) quantities are unknown. They note that factors such as population growth and economic development will considerably modify phosphorus consumption, and that given that phosphorus is essential for feeding mankind, efforts should be engaged to collect better data and build better models."

SCOPE Newsletter: www.ceep-phosphates.org/Newsletter/shwNewsList.asp?NID=3&HID=4

Cheers,
Philipp

Dear all,

The e-mail below is from Hakan Jönsson (well-known Professor at SLU University in Sweden). He has allowed me to copy it to here. The e-mail came about as part of the discussions on the update of the factsheet of the SuSanA working group 5 (productive sanitation and reuse), see here: forum.susana.org/forum/categories/58-wg-...roductive-sanitation

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“The life time of the reserve does not say how long the reserve will last! It is just a simple description of how large the presently known reserve is in terms of the present use of that element. Thus I propose the wording:
The prospects for potassium (or potash) are comparable with phosphorus. The size of the currently known reserves corresponds for potassium and phosphorus to 250-300 and 350-400 years, respectively, of production at the present rate. However, those estimates have to be taken with care as they neither reflect other factors like population growth, continuously increasing extraction rates and rising costs for energy-intensive mining nor the potential discovery of new deposits.

I personally think that there is no solid evidence that there is any risk at all of a peak-P or a peak-K over the coming centuries: Over the last 16 years, the production of rock phosphorus has increased by 28% (from 1,37E+08 to 1,76E+08 metric tons), while the known economic reserves of rock phosphorus have increased by 491% (from 1,10E+10 to 6,50E+10 metric tons). Still in the calculations by Arno, only the increase in production is included and no increase in the reserve. There is no projection included that we will find, or by new technology develop, any new reserve of phosphorus over the coming centuries. Is it really probable that the increase in reserves, which has occurred both for zinc, oil and phosphorus, for phosphorus totally stopped at the end of year 2010? That we during the coming 200 years will not discover any more economically exploitable resource? It might also be interesting to note that the life time of the phosphate rock reserve 1995 was 80 years, while it 2010 was 369 years, which I also think shows that it is not that easy that the reserve steadily decreases. Instead it seems that it often stays about constant and for some elements, e.g. phosphorus it increases.

Thus, I really think we, in our work towards sustainability, should focus on the nutrients that give the largest added value to the farmer here and now. On some soils it is phosphorus, but I am quite convinced that in most locations it is the nitrogen, while on some soils it is the potassium that can boost the crop the most. Nitrogen is also the most important element from energy and climate gas perspective.”

All the best,
Håkan