Climate Change Impacts to Crop Distribution

The next California? Projected shifts in bioclimatic zones of perennial fruit and nut crops into the Northwest under climate change

Respectfully borrowed without permission from Mother Jones.

Respectfully borrowed without permission from Mother Jones.

A warming climate may have detrimental impacts to US agriculture, particularly in California where rising temperatures and an uncertain water supply present challenges for sustaining productivity of high market value perennial fruit and nut crops. However, a warming climate and lengthening growing season may mean that the Northwest will be less energy-limited for some of these perennial crops that are currently grown in California.

My research uses biophysical requirements of specific crops to map the thermal suitability of several perennial fruits and nuts across the Northwest by the mid-21st century. Further, because perennial crops may be particularly susceptible to one anomalous year (for example, an extremely cold winter) and such factors are often ignored in assessments, the viability of thermal suitability given interannual variability is also being examined. I am interested in examining the spatial distribution of horticultural crops such as almonds, oranges, walnuts and peaches using both established species distribution modeling techniques as well as models built on the phenology of individual crops. I use the term “alternative agriculture” because the fruit and nut crops my research examines are not currently grown on a large scale across the Northwest, and would therefore be alternative to currently grown crops. Should the Northwest be thermally suitable for cultivating some of California’s “at risk” fruit and nut crops, there are broad implications for regional land use and management planning, water resource planning, and regional and national food security and economics.

This work was undertaken in 2 parts. The first compares the ability of mechanistic and empirical models to capture the distribution and viability of almonds under current climate conditions and models the current potential geographic distribution of almonds across the Southwest (more on this here). The second examines changes in almond viability and distribution under climate change and expands the study area to include the Northwest, as it is hypothesized that climate change will result in a northward shift of potential almond cultivation locations (more on this here).

Related research explored the geographic shift in USDA plant hardiness zones under climate change, changes in average and coldest winter minimum temperatures under climate change, and the climate velocity of average winter low temperatures and coldest winter low temperatures between contemporary and mid-century periods.