A tip of the hat to Geoff Simon for finding this one.
Corn, or maize, is foundational—along with rice, wheat, soyabean—to global food security, serving as a critical source of nourishment for both humans and livestock. Over the past few decades, increases in atmospheric CO2 from industrial emissions have tracked with notable boosts in corn yields.
Between 1900 and 2024, the national corn yield in the U.S. rose to 183 bushels per acre (bu/A) from just 28 bushels. During the same period, atmospheric CO2 increased from 295 parts per million (ppm) to 419 ppm. Worldwide, corn yield rose from a mere 29 bu/A in 1961 to 86 bu/A in 2021.
This phenomenon is not merely coincidental; it is deeply rooted in the physiological characteristics of corn as a C4 category plant. C4 plants like corn – so named for the number of carbon atoms in their photosynthetic product — possess unique biochemical pathways that make their photosynthesis particularly efficient under high concentrations of CO2 and elevated temperatures. Such plants employ a mechanism that concentrates CO2 in specialized structures called bundle sheath cells.
Higher CO2 levels also improve water-use efficiency in corn, which is particularly beneficial where water supplies are limited or during droughts. This efficiency translates into enhanced growth rates and potentially greater yields. In fact, researchers say that “less water will be required for corn under a high-CO2 environment in the future than at present.”
One wonders if corn might be grown above the Arctic Circle? Corn, from seed to maturation, 60 to 100 days based on variety. The "warm season" in Barrow, Alaska, lasts 3.3 months = 99 days. Wheat? Slightly longer.
