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More CO2, Less Protein

Climate change may not only devastate food crops, but also diminish plants' nutritional value.

crops in a severe drought

Photo: Shutterstock

Higher levels of carbon dioxide in the atmosphere negatively affect plants' ability to turn nitrogen into proteins.

By now you’ve certainly heard that climate change will not only make the planet warmer but also potentially cause or worsen all sorts of problems. It will cause drought in some places and torrential rain in others, leading to crop failures and food shortages.

Green Protein

According to new studies, climate change also seems likely to diminish the nutritional value of food. Scientists at U.C. Davis found that higher levels of carbon dioxide in the atmosphere negatively affect plants’ ability to turn nitrogen in the soil into proteins that make plants nutritious.

The researchers looked at samples of wheat grown in air enriched with carbon dioxide, raising the CO2 level to what climate scientists expect it to be in a decade or two.

And they found that the elevated CO2 inhibited the plants’ ability to convert nitrate, a common form of nitrogen, into protein.


Other studies have found similar results. Overall, protein levels in grains including wheat, rice and barley decline by an average of around 8 percent when grown in a CO2‑enriched atmosphere.

Which means that if and when CO2 reaches levels expected by climatologists, the amount of protein available to people could drop by as much as 3 percent over the next few decades.

How exactly will such a decline affect our health? It’s too soon to tell. But alongside rising sea levels and the potential for increasingly erratic weather events, less nutritious food is yet another reason to be concerned about climate change.

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