Global response patterns of major rainfed crops to adaptation by maintaining current growing periods and irrigation

Increasing temperature trends are expected to impact yields of major field crops by affectingvarious plant processes, such as phenology, growth, and evapotranspiration. However, future projectionstypically do not consider the effects of agronomic adaptation in farming practices. We use an ensemble ofseven Global Gridded Crop Models to quantify the impacts and adaptation potential of field crops underincreasing temperature up to 6 K, accounting for model uncertainty. We find that without adaptation, thedominant effect of temperature increase is to shorten the growing period and to reduce grain yields andproduction. We then test the potential of two agronomic measures to combat warming-induced yieldreduction: (i) use of cultivars with adjusted phenology to regain the reference growing period duration and(ii) conversion of rainfed systems to irrigated ones inorder to alleviate the negative temperature effects thatare mediated by crop evapotranspiration. We find that cultivar adaptation can fully compensate globalproduction losses up to2Koftemperature increase, with larger potentials in continental and temperateregions. Irrigation could also compensate production losses, but its potential is highest in arid regions,where irrigation expansion would be constrained by water scarcity. Moreover, we discuss that irrigation isnot a true adaptation measure but rather an intensification strategy, as it equally increases productionunder any temperature level. In the tropics, even when introducing both adapted cultivars and irrigation,crop production declines already at moderate warming, making adaptation particularly challenging inthese areas. (c) The Authors