Impact assessment of soybean yield and water productivity in Brazil due to climate change

In the next decades, the population is expected to rise by more than two billion people, and the projections of climate change have been considered as one of the greatest future challenges for world food security. Soybean represents more than 60 % of all plant protein produced in the world, and Brazil is the largest world exporter and the second-largest producer. In this paper, we simulated soybean yields for 16 strategically selected agroclimatic zones (CZs) to represent Brazilian production. Experiments conducted throughout the country were used to calibrate the CROPGRO-Soybean model for Brazilian conditions, for the main maturity groups used in Brazil, to simulate current and 40 future climate scenarios, provided by Coupled Model Intercomparison Project 5 (CMIP5) for 2050 in the both 4.5 and 8.5 representative concentration pathways (RCP). We found soybean yield varying by +1 to +32 % across 16 CZs in the average scenario of future climate when compared to the current yields. Yet, we found an increase of about 5% in the yield production risk for RCP 8.5. The main reason for such results was associated with the positive effect of increasing CO2 on crop water productivity, which overcomes the negative effects of temperature and water stress increases on rainfed Brazilian soybeans.

Automated summary

In the coming decades, the global population is expected to increase by over two billion people, with climate change projections posing one of the biggest challenges for world food security. Soybean, representing over 60% of all plant protein production globally, is predominantly produced in Brazil, the largest exporter and second-largest producer. This study simulated soybean yields in 16 strategically selected agroclimatic zones in Brazil under current and future climate scenarios, finding an average yield increase of 1% to 32% across the zones in the future.