Two Columbia University researchers report that a 1 ppm increase in CO2 equates to a 0.5 percent, 0.6 percent, and 0.8 percent yield increase for corn, soybeans, and wheat, respectively. Viewed retrospectively, 10 percent, 30 percent, and 40 percent of each crop's yield improvements since 1940 are attributable to rising CO2. They note that the Green Revolution has significantly increased agricultural yields around the world with input usage, mechanization, irrigation, and improved crop genetics all being identified as drivers of yield growth. Their new approach to measuring the contribution of CO2 is very robust. The researchers assessed the CO2 fertilization effect on US agriculture using spatially-varying CO2 data from NASA's Orbiting Carbon Observatory-2 (OCO-2) satellite covering the majority of US cropland under actual growing conditions, and NOAA’s CarbonTracker. They employed three separate approaches that isolated both time-series and cross-sectional variation.
Corn yields had been relatively stable from the 1860s to around 1940. From 1940 to 2020, corn yields increased by a factor of six. Soybeans and wheat yields exhibited a three fold increase over the same period. CO2 has clearly contributed to this growth.
Is is important to note that while climate change is predicted to increase the occurrence of extreme heat and significantly reduce yield potential, part of the estimated damages may be offset by yield gains from rising CO2. Frédéric Bastiat would be proud of this good economic thinking.
Matt Ridley also notes the positive value of global greening.
Bjorn Lomborg, author of False Alarm, Cool It and Skeptical Environmentalist, and president of the Copenhagen Consensus think tank offers smart solutions through economic prioritization.
CO2 is our friend, not our enemy.
You can learn more about these ideas in our forthcoming book, Superabundance, available for pre-order at Amazon.
Gale Pooley is a Senior Fellow at the Discovery Institute and a board member at Human Progress.
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