Monday, September 15, 2025

Corn And CO2 -- September 15, 2025

Locator: 49108CORN.

Re-posting, from September 20, 2024. Link here.

This was a big story for me. While in college, I participated in a study on the North Slope, Barrow, Alaska, studying the CO2-utilizing efficiency of the grasses there.

Locator: 48343CORN.

A tip of the hat to Geoff Simon for finding this one.

Link here.

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.