A Biased Anti-Warming, Anti-CO2 Model Fails To Account For Profoundly Positive Effects Of Rising CO2

It turns out the benefits of rising CO2 concentrations offsets any projected agricultural damage from climate warming.

In 2023 US EPA (Environmental Protection Agency) activists dubiously raised the “social cost of carbon” (SCC) five-fold due to unsupportable forecasts of agricultural deterioration and declining crop yields resulting from doubled CO2 and consequent climate warming.

The 500% SCC hike was based on a biased-negative model that neglected the significantly positive crop-yield benefits of rising CO2 concentrations.

The analysis the EPA relied upon for its dubious accounting was found in modeling papers (Moore et al., 2017 and Challinor et al., 2014) that tendentiously neglected multivariate factors in agricultural processes (e.g., precipitation changes, atmospheric CO2 changes, water-use efficiency, adaptation, technology…) and primarily focused on an assumed negative effect from a warming climate.

But now a new analysis that does not neglect all these other factors – especially the highly beneficial CO2 fertilization effect – finds any future warming, even up to 5°C, will still result in a net positive effect on crop yields.

“The negative temperature effects are fully offset by gains from CO2 fertilization and adaptation.”

“These coefficients imply that the atmospheric concentration of CO2 doubles from 280 to 560 ppm and causes 3°C warming, the combined effect on yields would be, on average, -14.7% (due to warming) plus 16.8% (due to CO2 fertilization) for a net effect of +2.1%.”

“But after incorporating the newly-available data the conclusions change such that global average yield gains of all crop types under CO2-induced warming are positive even out to 5°C warming.”

Image Source: McKitrick, 2025