Does Higher Atmospheric CO2 Content Threaten Human Health?

The risk isn't anything we haven't seen or can't counter.

By Calvin Beisner Published on July 23, 2018

Last month National Public Radio reported that “As Carbon Dioxide Levels Rise, Major Crops are Losing Nutrients.” It cited Harvard’s Sam Myers as saying this could be a big problem for someone “just barely getting enough of that particular nutrient.” He added that it “would [be] more harmful when that person gets a meaningful amount of a nutrient from the crop that’s losing nutritional value.”

Nutrient density does decline in some crops as carbon dioxide increases in the air. But does that pose a risk? And if so, what can we do about it?

The Distinction: Content Versus Concentration

Dr. Craig Idso, of the Center for the Study of Carbon Dioxide and Global Change, explains that the decline in nutrition is generally small. It usually amounts to less than 5 percent.

Further, reduced nutrient concentration doesn’t always occur. Where it does, it isn’t uniform. Different varieties of the same crop respond differently. Some lose some nutritive value under enhanced CO2, but others gain it.

It’s also important to distinguish nutrient content from nutrient concentration. Though concentration falls in some varieties, content almost always increases.

“The increase in roots,” Idso explains, “allows the plants to explore more soil and gather a greater nutrient content that is then distributed among the CO2-enhanced biomass, where it is sometimes diluted because the growth enhancement is so large. When it is diluted, one can view it in another light, that the plants become more efficient in using nutrients, i.e., their nutrient use efficiency increases.”

Usually, taking a multivitamin supplement or eating an extra bite or two would make up for reduced nutrient concentration. Because more carbon dioxide raises crop yields, foods become less expensive, making the extra bites easy to afford.

Countering the Risk

Further, a slight change in the quantity or mix of fertilizers applied to soil can restore full nutrient concentration.

Does rising atmospheric carbon dioxide pose a risk to nutrition, then?

Well, yes. But it’s a small risk that can be overcome easily. One could eat slightly more of the affected crops or other sources of the same nutrient. Or one could take a multivitamin supplement. Or farmers could use a bit more or slightly different fertilizer.

What is not sensible is assuming that human beings, who have made all kinds of adjustments through the ages, will fail to take such steps to counter the risk.


Calvin Beisner, Ph.D., is founder and national spokesman of The Cornwall Alliance for the Stewardship of Creation.

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  • Trilemma

    Seems to me that the loss of minerals from farm land and the use of pesticides pose bigger risks to human health.

    • Karen

      Exactly. The pesticides and fertilizers necessary to counter this effect of global warming will destroy what little is left of the oceanic biomass, but Monsanto will have a great 3rd quarter earnings report!

  • Vince

    NPR – oh, please. You can’t get more biased – or more hysterical.

  • Charles Burge

    Carbon Dioxide Fertilization Greening Earth, Study Finds

    “From a quarter to half of Earth’s vegetated lands has shown significant greening over the last 35 years largely due to rising levels of atmospheric carbon dioxide, according to a new study published in the journal Nature Climate Change on April 25.”

    nasa dot gov/feature/goddard/2016/carbon-dioxide-fertilization-greening-earth

  • Paul

    I wonder how much of my tax dollars was wasted to ‘discover’ this

  • Karen

    One more bit of ‘oh, global warming is no big deal’ idiocy. Meanwhile, the entire northern hemisphere is breaking heat and drought records this summer. Where, exactly, do you all plan to move once you’ve completely trashed Earth?

    • ncsugrant

      For the record, Karen, this article was about CO2. No mention of “global warming”.
      As for your claim that “… the entire northern hemisphere is breaking heat and drought records this summer.”, even the most ardent of alarmists have not expressed such an indefensible position.
      Those who use extreme rhetoric to avoid or silence any debate or discussion should be viewed with deep suspicion.
      The same “scientists” who claim elevated levels of CO2 will produce bad results still offer no plausible explanation for the observed climate changes over the past 800 years. In short, they admit that they don’t know what caused past climate changes (including those that pre-date the industrial revolution).

      • Karen

        Japan had the hottest day ever recorded a couple of days ago. Northern Europe is having a record-breaking drought and heatwave. Further, what is wrong with reducing our use of fossil fuels and our pollution? Why so much love for filth?

        • ncsugrant

          So, I live in the Northern Hemisphere. No record temps or drought. Do you think my ZIP code is the only one?
          As to the modern conveniences we all enjoy as result of carbon based fuel consumption, I would ask you to define “pollution”. I shall ignore your comment on my “love for filth”. Surely you can discuss this without the derogatory language.
          Back to the “pollution” debate. It seems that many people have become convinced that there is some alternative to carbon based fuel that emits lower “pollution”. If CO2 isn’t really as bad as the so-called green energy industry says it is, then they have quite a dilemma. It turns out that there are trade-offs with all forms of energy. There is an environmental impact to solar, wind, nuclear, and hydro.
          Speaking of the last two, they have near zero CO2 emissions. They were once favored by certain environmentalist groups, but seem to have lost out to the solar and wind industry lobby.
          I guess they were too few in number to buy enough influence?

        • Charles Burge

          And just 3 months ago, most of North America experienced the coldest April in 140 years. Are you going to blame that on global warming too?

        • Boris

          They don’t care about the planet. Jebus is coming!!! Any day now… no really.. any day now the signs are all here… for the last 2000 years… LOL

    • Gerrard

      I guess I will worry about it when it happens. Meantime, Dr. Roy Spencer doesn’t seem too concerned.

  • Ken

    The glo-bull warming cult is a religion. If you question their dogmas, you are an evil heretic.

    • Paul

      I’m a deplorable climate denying bitter clinger.

    • Boris

      No, you’re just stupid.

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