The influence of geomagnetic flux on global crop yields and income

Recent studies have shown that magnetic fields can influence plant growth and development. This research examines whether temporal variation in the intensity of the Earth’s geomagnetic field (GMF) affects the yields of food crops. To estimate this relationship I utilize data on the global yields of wheat, maize, rice, and soy at a 0.5 degree spatial resolution (approximately 55 km2), along with information on GMF intensity over the years 1985 to 2015. Results from a two-way fixed effects model suggest that a 1 mG increase in GMF strength is associated with a one percent increase in wheat and maize yields, a 1.8 percent increase in rice yields, and no significant effect on soy yields. To examine whether these effects impact economic outcomes, I obtain country-level measures of per capita income and value added in agriculture from 1960 to 2020. Two way fixed effects estimates show that a 1 mG increase in average country-level GMF strength is associated with a 0.5% increase in per capita value added in agriculture, and a 0.7% increase in per capita GDP. These results suggest that information on GMF intensity may serve as a useful addition to models of crop forecasting, and may help agronomists anticipate changes in agricultural income and food supplies.