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Ozone and Planetary Food Security: The Bad News and Good News
Volume 15, Number 17: 25 April 2012

In a "Food Security" paper published in the Journal of Experimental Botany, Wilkinson et al. (2012) write that "ground-level ozone pollution is already decreasing global crop yields (from ~2.2-5.5% for maize to 3.9-15% and 8.5-14% for wheat and soybean, respectively)," and they provide a concise one-sentence summary (comprising the bulk of the paragraph below) of how ozone pollution negatively impacts the yields of a variety of crops, thereby threatening global food security.

The bad news, as the four researchers describe it, is the fact that "ozone causes visible injury symptoms to foliage; it induces early senescence and abscission of leaves; it can reduce stomatal aperture and thereby carbon uptake, and/or directly reduce photosynthetic carbon fixation; it can moderate biomass growth via carbon availability or more directly; it can decrease translocation of fixed carbon to edible plant parts (grains, fruits, pods, roots) due either to reduced availability at source, redirection to synthesis of chemical protectants, or reduced transport capabilities via phloem; decreased carbon transport to roots reduces nutrient and water uptake and affects anchorage; ozone can moderate or bring forward flowering and induce pollen sterility; it induces ovule and/or grain abortion; and finally it reduces the ability of some genotypes to withstand other stresses such as drought, high vapor pressure deficit, and high photon flux density via effects on stomatal control."

The good news, as we more simply and succinctly describe it, is that the ongoing rise in the air's CO2 content tends to negate all of the bad news. And one can read all about it by perusing the many reviews of pertinent scientific papers we have archived in our Subject Index under the heading of Growth Response to CO2 with Other Variables (Ozone - Agricultural Species), where we focus largely on wheat and soybeans, the two crops Wilkinson et al. point to as being especially vulnerable to the deleterious effects of ozone pollution.

Sherwood, Keith and Craig Idso

Wilkinson, S., Mills, G., Illidge, R. and Davies, W.J. 2012. How is ozone pollution reducing our food supply? Journal of Experimental Botany 63: 527-536.