Vulnerabilities and adaptive capacities of selected southwestern crops to climate change

TitleVulnerabilities and adaptive capacities of selected southwestern crops to climate change
Publication TypeConference Paper
Year of Publication2015
AuthorsElias E, Rango A, Steele C, Havstad K
Conference NameClimate Prediction Applications Science Workshop (CPASW)
Date Published03/2015
Conference LocationLas Cruces, NM
ARIS Log Number321687

By the middle of the 21st Century, maximum annual temperatures in the Southwest (SW) are expected to increase by 2-4 C with the highest increases occurring in the summer months of Jun-Aug. While annual precipitation may remain similar to 1971-2000 values, Mar-May precipitation in the SW may decline up to 20% in certain locations. These projections, along with likely increases in extreme events such as heat waves and droughts, will impact crop production via multiple pathways including water scarcity, temperature sensitivity and cumulative ecosystem effects. We present examples of the likely consequences for specific annual and perennial crops common in the SW United States. The main field crops in the SW by area and production value are alfalfa, cotton, wheat, corn and rice. The optimum temperature range for maximum grain yield of these crops will be exceeded in broader spatial and temporal scales across much of the SW. The winter chilling requirements for stone fruit and tree nuts will not be met by the middle of the 21st century, resulting in lower yields. The observed "summer slump" in alfalfa, which is related to high temperatures in southern CA and AZ, will likely continue and expand. There are several adaptive measures that can be implemented to ensure yields. Ensuring adequate irrigation water supply is necessary. Certain crops, such as barley and safflower, are well adapted to arid environments and may represent a viable substitute for more water-intensive and vulnerable crops. Planting drought tolerant cultivars may help sustain yields. For certain crops, such as corn, wheat and stone-fruits, growth in regions representing optimal thermal ranges may be the best option for sustained production.