Thanks to K. Ingold, an institute member, who sent us a lead on this story.
A few years ago, Smithsonian paleontologists decided to recreate the atmosphere of 5,000 years ago — when corn was domesticated — to study what the effect would be on maize’s wild progenitor, teosinte. Today, teosinte is a weed growing in ditches across Mexico. It looks like corn with long branches where one expects ears and little seed pods instead of large cobs. But 5,000 years ago, the atmosphere was 3.4–5.4°F cooler and held 140 ppm less CO2. than today’s 405 ppm. When a greenhouse was held to these prehistoric conditions, teosinte grew in a form that looked much more like maize, meaning it was less of a leap to breed this plant into its domesticated form.
While not looking to corroborate any particular modern hypothesis, this study illustrates how a change in atmospheric composition and growing conditions can have an impact on floral morphology. This has ramifications for any animal that depends on plants to live (note: this means you).
In a recent Politico article entitled “The Great Nutrient Collapse,” Irakli Loladze’s hypothesis that increased exposure to CO2 has a positive impact on plant sugar production. In fact, it encourages the storage of carbohydrates and reduces the amount of other nutrients available. Many people looking at agriculture — myself included — had known about the decrease in “good” nutrients in modern, high-yielding varieties better suited for industrial agriculture and food production. For example, when working in a bread bakery, the bakers bemoaned the sorry state of modern flour with its high water and carbohydrate content and low protein and nutrient proportions. We had, though, assigned all the blame to selective breeding, that is, the idea that agriscience had purposefully bred plants this way. In fact, it might have as much to do with the changing atmosphere as it does selective breeding.
Loladze’s study seems to suggest an oft-repeated maxim of the institute: quality is inversely related to quantity. As plants are more productive in the enriched CO2 environment, they do not produce all nutrients at a greater rate — only the sugar-derived components are increased. Instead of running out of calories to feed the world’s population, we may see people and animals developing protein and nutrient deficiencies.
Now that we’re aware of this problem, the prudent thing would be to select plants that still produce a balanced nutritional profile in environments of elevated CO2, but this would reduce the yield-per-acre of our staple crops, an anathema to industrial agriculture. Unfortunately, the profits and status quo will continue to select large-scale agricultural seed plants for quantity over quality when the total amount of food grown each year is sufficient for every human on earth (and then some). A plan to reduce food waste, improve distribution, and increase nutritional value would be a proactive step forward, but not one that would be profitable in the short term.