An analysis of observed and predicted extreme heat and precipitation trends across four pulse producing regions in North America: North Dakota, Montana, Saskatchewan, and Northeastern United States

Abstract The consumption of plant-based proteins in lieu of animal proteins is the most important dietary shift that would be needed to keep the world under 2 °C of warming, and this shift would require a dramatic increase in the percentage of cropland devoted to nuts and pulses (Peters et al 2016 Elementa 4 000116). As the demand for plant-based proteins, like pulse crops, continues to grow, it is critical to understand the impact of climate change on crop production. In this paper, we study two climate-related stressors for pulse production in North America: extreme heat and excess moisture during harvest. Pulses must be dried on the plant before harvest, requiring a 7 day dry spell before harvest or the use of Roundup (glyphosate) to kill the plants quickly. However, little is known about the changes in frequency of hot extremes or dry spells during harvest in pulse-growing regions. We analyze climate trends using the Unprecedented Simulated Extreme Ensemble method with historical data, and we compare results to the average future change in the ssp370 scenario, which is a medium-high climate change scenario of 40 models of the the Coupled Model Intercomparison Project (CMIP6) in four pulse growing regions across North America: Montana, North Dakota, Saskatchewan, and the Northeast USA. We find that temperature extremes have increased in all regions, with extreme events 3–4 times more likely today than in 1981, increasing the risk of crop loss. August and September rainfall during the harvest months has been decreasing in the Midwestern regions and it is projected to continue to decrease in the future; however, the likelihood of a wet August in the Northeast has nearly doubled. Even with this drying trend, farmers cannot assume that they will have a 7 day consecutive dry spell that would enable natural drying of pulses without synthetic drying agents like glyphosate. Future expansion of pulse production should incorporate adaptation measures to manage extreme heat and the potential for rain events during harvest.