Can Global Warming Reduce Nutrition?

According to a recent report in Science Advances (summarized in the Vox) increased atmospheric CO2, a key feature in global warming, can result in reduced crop nutrition.  They demonstrated this effect using rice, a staple crop that feeds much of the world.  This would seem threatening, since poor crop nutrition impacts food webs all the way from the soil to the plate.  Human health and the productivity that drives our economy are both impacted by crop nutrition, so clearly, we don’t want to see a decline.

Of course, it is not surprising that scientists using conventional practices found a decrease in crop nutrition as they increased levels of CO2 that plants were exposed to.  In my Managing Your Microbiome online course, I discuss work by D. Davis that shows as crop yields increase, nutritional value decreases.  It has also been known for a long time that increased CO2 can boost plant growth by increasing photosynthesis.  In fact adding CO2 to boost production was a common strategy used in laboratory growth chambers throughout the years that I was involved with institutional biotech research.  So the discovery itself is not alarming or novel.  This is simply one more indicator that we need to re-think the way we are managing atmospheric carbon.

The Vox article suggests that there is a need to find new ways to help plants cope with rising atmospheric CO2-possibly by engineering plants to tolerate more CO2, or by adding more costly, and presumably chemical nutrients.   This approach is both inefficient and unnecessary!  In fact, efforts to develop more CO2 tolerant plants may actually deter growers and consultants from addressing the problem with simple solutions that are already at hand.

It has already been shown that soil microbes can remove excess CO2 from the atmosphere.  The only reason these microbes are not functioning adequately now is because our management strategies destroy them.  While the potential to develop new technologies to save us from this advancing threat sounds promising, the fact is that basic approaches to maintaining soil health are already available, and some of these are as old as civilization itself.  Why invest in costly new research to develop technologies that are equally costly to implement, when viable solutions have already been tested and proven both scientifically and historically?

It is well known that management practices which build soil organic matter  and emphasize biodiversity in the living fraction, were largely abandoned in the last century as society tested and implemented new chemical and genetic technologies.  But today we are learning that these new technologies were inadequately tested, and that their implementation damaged the soil microbial fraction so important for managing carbon and all other nutrients.     Today we know that when soil biota are allowed to prosper, they remove excess CO2 from the atmosphere, mobilize nutrients, and make them available to crops. Regenerative farming practices that maximize soil biodiversity and build or preserve healthy levels of soil carbon act as sinks for excess atmospheric CO2 while producing nutritious crops.  These practices also help farmers remain profitable.

Sadly, many farm soils today are managed without attention to soil biology, which means the food you purchase from the grocery store may already be nutrient depleted.  This is one reason why nutritional supplements that include necessary vitamin and mineral nutrients are so critical for good health.  It may also be one reason that chronic disease has become so common.

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So before we launch campaigns to engineer more crops with more questionable long term ecosystem effects, let’s implementing what we already know.  Growers-build your soil health so you can produce nutritious food.   Consumers, buy foods grown on healthy soils, and use supplements to address remaining deficiencies.

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