Impact assessment of common bean availability in Brazil under climate change scenarios

CONTEXT: Brazil is one of the main producers of common beans (Phaseolus vulgaris L.), which have high nutritional value as human food. The climate changes predicted in the 21st century might be a possible threat to the planet's food security, given the expected population increase, and hence, increased demand for food. OBJECTIVE: This study aimed to project the impact of climate change on common bean cropping systems using an upscaling climate approach and crop modeling to represent the Brazilian production regions. METHODS: We considered the representative CO2 concentration pathway scenarios (RCPs) 4.5 and 8.5 presented by the 5th IPCC Assessment Report from 20 atmospheric global circulation models covering the main bean producing region in Brazil. The well-calibrated CROPGRO-Drybean crop model simulated two representative cultivars of the "black" and "colors" types and three cropping seasons applied by Brazilian farmers. RESULTS AND CONCLUSIONS: On average, we found that yield increased by 5.56% and 9.12% for the RCP 4.5 and 8.5 scenarios, respectively. Increased photosynthetic efficiency due to the increased atmospheric CO2 concentration was identified as the main cause of this yield increase. Crop respiration rates increased due to the raised air temperature, and were responsible for increasing the probability (production risk) of not meeting the future domestic demands for grains to 10.13% and 8.34% for the RCP 4.5 and 8.5 scenarios, respectively. For the national supply of grains, estimates pointed to a future in which crop production will probably rely more on area expansion than yield gains by crop intensification. SIGNIFICANCE: Our findings emphasize the need for new policies for land utilization and investments in scientific research programs aimed towards genetic adaptation in all main Brazilian crops in the face of potential climate change.