New Report Details Possible Impact of Climate Change on Southern California Specialty Crops

  • Aug 18, 2020

A new report released by the California Department of Food and Agriculture (CDFA) and the Climate Science Alliance examines observed and potential changes in Southern California agricultural regions and the impact these climate-based changes will have on farmers. The main conclusion of the 2020 Climate Change Impacts for Specialty Crops – Southern California Region report is that Southern California farmers will need to be ready to adapt to the changing climate, and the report’s large-scale findings will need to be tailored to local needs. The researchers also acknowledge that an effort must be made to connect researchers and technical-assistance specialists with farmers who are facing climate change challenges on a daily basis.

According to the report, as a whole, the Southern California region is likely to experience a climate profile with more extremes over the next several decades.

  • Average temperatures are expected to increase with higher daily maximum temperatures and more frequent and intense heat events
  • Wintertime, nighttime and daily minimum temperatures are expected to rise
  • More extreme variability in temperatures is expected, with more frequent cold outbreaks
  • Higher year-to-year variability in rainfall with more frequent and severe droughts, as well as extreme precipitation events
  • Wildfire risks will heighten due to increased temperatures, dry conditions and Santa Ana winds

The predicted rise in daily and nighttime temperatures may impact California avocado agriculture in a variety of ways.

  • Lower soil moisture and increased evaporation could lead to reduced water availability, increased costs of water and higher irrigation demand
  • Increased salinity issues due to drought, low precipitation and limited water availability
  • Decline in crop yields due to increased rate of respiration
  • Increased tree water use due to Santa Ana wind events
  • Sensitivity to warmer August temperatures could negatively impact avocado yield
  • Potential for up to a 45% reduction in avocado yields statewide by 2060 due to warming temperatures
  • Suppression of persea mite populations due to extreme heat waves
  • Reduced risk of frost damage due to warmer winter minimum temperatures
  • Increased wildfire risks
  • Production may shift to coastal Central California as the state warms

In particular, San Diego County could see more intense extreme-precipitation events and greater warming inland compared to the coast. Projections indicate the average hottest day per year in the county could reach 110-125˚F in the desert regions and 100-111˚F in the coastal areas.

The report notes a variety of climate-smart agricultural practices, including cover crops and composting/mulching. California avocado growers can read about California avocado grove-specific research and recommendations for cover crops and mulching on the California avocado growers website.

The study sought input from producers and gathered their feedback concerning the climate challenges they are currently facing and their concerns for the future. The respondents overwhelmingly noted they were “seeing and experiencing all of the listed climate change drivers, including extreme weather events and variability, drought, temperature changes, precipitation variability, and wildfire.” They also identified the extreme Santa Ana wind events as a factor in their production. They noted the variability of the weather made it more difficult to plan, that water availability was a major concern, that their efforts to adopt efficient technologies was undermined by flooding or early frosts, and that weeds seemed to be adapting quickly to the changing climate and were becoming more difficult to manage.

The report does an effective job of collecting input from growers and sharing anecdotal evidence that may be of great interest to California avocado growers. This portion of the report has individual sections concerning growers’ experiences with:

  • Weather variability
  • Drought
  • Precipitation and water resources
  • Temperature
  • Wildfire

The report also contains a comprehensive list of challenges faced by producers concerning funding and resources, economic viability, and climate data and planning.

According to the report, producers are “already pursuing innovative and creative solutions to deal with extreme weather and address the long-term impacts of a changing climate.” The latter half of the report focuses on proposed solutions and supports, producers’ climate-smart actions and strategies, research needs, and recommendations concerning what new resources would be most beneficial to growers.

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