Climate change: agricultural yields increasingly fluctuating, according to a study

This observation made by Jonathan Proctor, from the University of British Columbia (UBC) in Vancouver (Canada), and his colleagues is not insignificant since poor harvests can threaten farmers' activities, lead to a surge in food prices, or even be the cause of famines.

"Not everyone is a farmer, but everyone needs to eat," so "when harvests become more unstable, everyone will feel it," Jonathan Proctor said in a UBC press release. Using mathematical models, the researchers compiled weather records and satellite images of ambient temperature and soil moisture, as well as yield data for three common food crops: corn, soybeans, and sorghum.

According to their calculations, with each additional degree, the variability of yields of these three cereals from one year to the next increases by 7.1% for corn, 19.4% for soybeans, and 9.8% for sorghum. The main driver of these more frequent fluctuations is the combined impact of increasing average temperatures, temperature variability, and drought.

These factors combine in a vicious cycle where heat dries out soils, exacerbating heatwaves, while global warming exacerbates the process. With increasingly variable yields, the likelihood of lower harvests increases, and very poor vintages will also become more frequent. According to the researchers' calculations, with a 2°C rise above current conditions, episodes of very poor 100-year harvests could occur every 25 years for soybeans, every 49 years for corn, and every 54 years for sorghum.