Thursday, September 13, 2018
In the early afternoon of Friday, July 6, 2018, those of us on the Gaviota Coast were experiencing unprecedented temperatures, as did most of Southern California. Around 3 p.m., an already hot day suddenly became an extremely scary heat event. Over the next four hours, hundreds of thousands of dollars’ worth of heat-related damage occurred on agricultural land across the Gaviota Coast, and new high temperature records throughout Southern California were set.
It is hard to say what the future climate has in store for us in Southern California, but the July 6 event was a wakeup call. Many climate scientists have predicted a general “heating up and drying out,” but there are also others who claim the opposite. Despite these divergent arguments, I can recall some past predictions that seem spot on.
In 2004, Lisa C. Sloan — currently the vice provost and dean of Graduate Studies at UC Santa Cruz, where she had been a professor of Earth Sciences — and her graduate student, Jacob Sewall, published the article “Disappearing Arctic Sea Ice Reduces Available Water in the American West” in the journal Geophysical Research Letters. Their study “simulate[d] the effects of reduced Arctic sea ice” and resulted in “a significant reduction in rain and snowfall in the American West.” Our drought in California with its “ridiculously resilient high pressure atmospheric ridge” has seemingly followed their prediction to a T.
Michael Mann, one of the country’s leading climatologists, referred to the Sloan and Sewall study in an interview with Joe Romm, former assistant secretary of the U.S. Department of Energy. He stated, “There is credible peer-reviewed scientific work by leading climate scientists, published more than a decade ago, that hypothesized that precisely this sort of blocking pattern would become more frequent with disappearing Arctic sea ice. Moreover, Arctic sea ice has declined precipitously in the intervening decade. So it seems quite clear that there is a potential connection, in a statistical sense, between human-caused global warming, declining Arctic sea ice, and the anomalous blocking pattern this winter that has added to other factors we know are tied to human-caused climate change (warmer temperatures and increased soil evaporation, and decreased winter snowpack and freshwater runoff) to produce the unprecedented drought in California.”
While the jury may still be out on the connection between declining Arctic sea ice and ongoing droughts in California, one thing I do know is that if the last four to five years are the new norm for Southern California, then we better begin adapting to these extremes: fire seasons that last 12 out of 12 months, bone-dry soils that lie parched for nine months out of the year, deluges that bring mountains down in minutes, and temperature extremes that will impress all but the staunchest of critics. How will our agricultural lands thrive if this is the new norm?
This brings up what some agriculturalists call climate-appropriate crops. There is no doubt that in our climate, most of the time, we can grow just about anything: from sub-tropicals (cherimoya, coffee, avocados, and mangos) to desert plants such as mesquite and prickly pear. With the sub-tropicals, it is often just a function of water; and lots of it. So how do we determine what is appropriate for our area's climate?
As with most things, the answer is not simply black and white. The grey area lies in how the crop is grown. For example, in its native habitat (southern Mexico and Central America), avocado trees grow as an under-story tree and need to be protected from sun scalding. Here in California, however, they are almost always grown in full sun. During our heat wave last month, it was the avocados that took a real hit. Not only did the heat ruin this year’s fruit, all of next year’s fruit, only just starting to grow, was lost as well. Many of the trees look as though they suffered an extreme frost event or even a fire.
In stark contrast to this, however, is Connor Jones, a colleague and fellow permaculture design advocate, who has chosen to honor the avocado and its native growth habits. Connor, who lives in the Ojai Valley, plants a nitrogen fixing tree as an overstory in and among avocados. The tipu (Tipuana tipu) tree, native to South America, is a fabulous shade tree with the ability to convert atmospheric nitrogen into plant-available nitrogen (otherwise known as a nitrogen fixer).
Connor noted that the avocados trees that were growing under tipus were more or less unscathed during the 112-degree July event (at the left of the photo above) versus the avocados on the neighbor’s property that were severely scorched and had dropped all their fruit (right side of photo). Connor explains:
"Canopy trees used as support species to productive crops have a multitude of benefits. In this case we can see how they helped avocados survive exceedingly high temperatures and low humidity. The avocados held their fruit and sustained only minor heat damage. A crop still ripens on these trees. The trees on the right are planted in the common fashion of high density monoculture with no protection; they lost all tender growth and fruit set.
"Some of the other benefits of incorporating canopy trees include, improved rainwater infiltration in soils, increase in soil carbon, erosion prevention, increased soil nitrogen, and reduction in irrigation demand. All of these additional benefits must be considered as the necessary tools for maintaining agricultural productivity in the present and future climate reality. Innovative strategies such as this will no doubt conserve water as well as protect species such as the avocado trees."
In the coming years it will be critical that landowners in Gaviota, and Santa Barbara in general, prove willing and able to adapt to our changing local and global conditions. Honoring our collective need to address such things as climate change can be seen as an opportunity and not a burden.
Guner Tautrim serves on the Board of Directors of the Gaviota Coast Conservancy and is a sixth-generation farmer on the Gaviota Coast practicing regenerative agriculture. He lives on the family ranch with the seventh generation.