About 70 years ago, Weston Price found evidence that US soils were
depleted.  Writing about phosphorous, which is essential for mammalian
health, he said ‘Now when we realize that a 60 bushel crop per acre of
wheat or corn will remove from the soil about 25 pounds of phosphorous per
acre, or one fortieth of the total content in the top 7 inches, we are
immediately confronted with the fundamental, controlling problem that we
have, accordingly, only enough phosphorous in the average soil for forty
excellent crops ...’  The idea has been picked up by other writers
(e.g., ‘Empty Harvest’) and by the organic movement which looked not only
at minerals, but also the way modern agriculture stripped the soil of the
humus and rich bacterial biomass (e.g., www.soilassociation.org) in which
our food plants evolved and thrived.

Now comes a startling new line of research findings which, in a nutshell,
demonstrates that the increase in atmospheric CO2 and the global warming
which accompanies it, accelerates photosynthesis and causes plants to grow
faster, but with a dilutes micronutrient content as they can’t absorb
micronutrients from the soil fast enough to match their increased
production of cellulose.  Organic gardeners and farmers had the answer to
soil depletion: nurturing the soils under their control.  But now they
have no individualized answer to the deleterious effects of the changing
air their plants breathe.

New Scientist magazine of 30 November 2002 has a feature on this research
centred on the work of the Princeton (US) biologist Irakli Loladze.

Loladze shows that plants grown under today’s atmosphere (with 30% more
CO2 than 250 years ago) and the atmosphere predicted for the year 2100
(with 100% more CO2) are impacting significantly on plants’ micronutrient
content, particularly iron, zinc, selenium and chromium.  He has focused
on the 32 elements of which all biomolecules are composed and homed in on
the 24 that are essential for the human body.  Pulling together all the
relevant data he could find from experiments with doubled CO2 he found
declines in almost every element studied.  In one study on rice, for
example, the research sowed nitrogen down 14%, phosphorous down 5%, iron
and zinc both down 17%.

So much for those fringe scientists in their think tanks who have been
spruiking for the past few years that rising CO2, and the increased
quantity of agricultural production which it is stimulating, is a free
lunch.  TINSTAFL!

The article tells us something I have not heard previously: that iron
deficiency is already the world’s biggest health problem with 3.5 bn
humans suffering mental and physical impairment as a result.  Zinc
deficiency, which leads to pregnancy complications and poor growth and
health in childhood, may be just as widespread.

What to do?  New Scientist tells us that fertilizing the soil will not
work, as farmers are driven by yield and there is no incentive at all to
switch the fertilizer regimes away from plant growth into keeping crop
composition optimal for human consumption.  The article concludes by
linking this ‘hidden hunger’ to obesity: our bodies are identifying the
need to eat more of whatever is around in order to satisfy the need for
the micronutrient levels our species have been evolutionarily adjusted to.

I have done my best here to summarize four pages of the magazine into 2800
words; please let me know if you have any questions and if they can be
answered from the New Scientist article I’ll publish an amended version at
http://www.evfit.com/co2.htm.

Keith

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