Climate change looms over California agriculture, threatening increased invasive pest problems, fewer winter chill hours, more saltwater intrusion, and weaker flood resistance. On the Central Coast, drought and temperature increase have become the most prevalent dangers to the area’s typically rich farmland.
Studies show projected climate-related declines in California crop yields, pressuring growers to adapt. A new report from California’s Natural Resources Agency aims to provide guidelines for adaptation.
JR DeLaRosa, assistant for climate change at the Natural Resources Agency, said the organization has spent nearly seven years mapping out how each California industry sector is vulnerable to three main impacts of climate change: temperature increase, precipitation change, and sea level rise.
The result: Safeguarding California: Implementation Action Plans, was compiled to provide actionable responses to climate change for each sector. For the agricultural sector, DeLaRosa said, these plans are particularly important.
“It becomes a little more complicated for [agriculture] in particular, because we have so many specialty crops,” he said. “Even minute changes in temperature have pretty big impacts to the types of crops that we’re growing.”
Temperature increase
Temperature-related threats include both gradual temperature increases and more intense and frequent heat waves, DeLaRosa said. These threats can potentially affect both crops and livestock.
“In livestock, heat waves and extreme temperature lead to heat stress, lower milk or egg production and changing disease epidemiology,” the Natural Resources Agency report said. “Crops are also impacted by increasing temperatures.”
Decreasing winter chill hours is particularly problematic for California fruit, Safeguarding California said. Environmental scientist Carolyn Cook, who helped lead the agricultural sector chapter in Safeguarding California, explained that winter is crucial for the development of many fruits and nuts.
“They require a period of dormancy during the winter where it’s nice and cold, to prepare them for bloom,” Cook said. “If they don’t get those hours of chill, they bloom sporadically and don’t get the best fruit set. We certainly have experienced a loss of chill hours already.”
In fact, the report predicted an 80 percent reduction in chill hours by 2100. It also said the warming climate could hurt California vineyards, many of which exist along the Central Coast.
“California’s premium winegrape regions will also be affected by increasing temperatures as grape varietals are sensitive to climate,” it stated. A California Department of Food and Agriculture (CDFA) climate change consortium report added that these effects could devastate the wine industry.
“Yield in [crops] like wine grapes and cherries could decrease dramatically to economically unsustainable levels,” the CDFA report said.
Safeguarding California turned to the CDFA report for suggestions on how to take the heat. The CDFA cited projects demonstrating heat adaptation for crops. These projects include structural, mechanical, or biological methods to reduce crop heat stress and crop-training systems to protect them from heat stress.
Rising temperatures could spur more serious pest issues, as well, Cook said.
California is already a hotspot for invasive pests, she said. The state experiences yearly invasions of foreign pests. But increasing temperatures could affect the life cycles of these bugs, making them more persistent and widespread.
“As temperatures warm, some species of pests may have more life cycles per year because temperature really impacts the development of, say, a caterpillar into an adult,” Cook said. “We imagine our climate may become more suitable to pests that do well in warmer climates.”
The report pointed out that additional pest pressures would likely lead to increased pesticide use, meaning increased cost to growers and the environment.
To tackle the pest issue, Safeguarding California recommended the CDFA develop pest-forecasting tools that account for climate change.
“The efforts will be ongoing with the intention of adopting predictive models that assist the department’s pest and invasive species programs to effectively control pest and invasive species populations and mitigate food crop losses,” the report said.
Precipitation change
“The drought is huge,” said DeLaRosa, who identified precipitation change as the biggest climate-related issue facing California agriculture.
But drought means more than just a lack of rain, according to Safeguarding California. It means precipitation will fall in fewer but heavier events, which would increase flood risk and make water management more difficult.
“It’s a bit scary because we’re talking about how some of these major impacts could become more frequent and more intense,” DeLaRosa said. “And that’s scary because some of these impacts could be devastating. People’s lives are at risk.”
Safeguarding California looks to the Healthy Soils Initiative to increase water retention for soil and to prevent flooding. Gov. Jerry Brown introduced the initiative, which aims to build the organic matter content in soils, in his proposed budget for the 2015-2016 fiscal year.
“It’s the utilization of certain soils in compost to help with many different aspects of the agricultural sector,” DeLaRosa said of the initiative. “Compost can have more nutrients, higher crop yield, and there’s potential for greater water retention.”
Safeguarding California said soils rich in organic matter are also more resistant to erosion, a risk posed by extreme weather events.
Drought has also led to a serious depletion in water available from streams and reservoirs, the report said: “In 2014 and 2015 California agriculture experienced the greatest ever reduction in water availability due to low stream flows and low reservoir levels.”
This has meant the loss of billions of dollars and tens of thousands of seasonal jobs, the report said.
Aside from soil-based projects, Safeguarding California cited CDFA-recommended actions to cover crops and utilize crop rotations to “efficiently utilize irrigation systems and prevent runoff,” as well as water conservation strategies for growers to implement in their water storage and irrigation techniques.
Sea-level rise
During times of drought, agriculture relies more heavily on groundwater for production and to keep crops and livestock alive. A 2014 California Water Foundation (CWF) report said groundwater basins on the Central Coast “are among the most threatened by present or future increases in groundwater demand.”
Environmental Scientist Cook said a shortage of groundwater is the most immediate challenge facing the agriculture industry.
“We’re still in a drought throughout California, even in February or March. If we have more droughts ahead of us, the way we manage our water might be different because we won’t be able to count on the snow pack,” Cook said.
Additionally, sea-level rise poses the risk of seawater intrusion into groundwater in coastal areas. The CWF report said the Central Coast’s supply of groundwater is at a particularly high risk for seawater intrusion.
“Seawater intrusion results in saline groundwater that is unsuitable for irrigation or domestic use, directly threatening the Central Coast’s economy, were many high-value, salt-sensitive crops, such as strawberries, are grown,” the CWF report stated.
The Pajaro Valley is a primary example of this issue, according to Safeguarding California. The valley receives a saltwater flow into its groundwater basin at a rate of 200 feet per year.
“This is to the detriment of the high-value vegetable and fruit growers in the region who are adapting with water conservation, but also must cope with impaired water quality and future uncertainty,” the Natural Resources Agency report said.
The report proposed additional research to explore solutions for the groundwater issue. One area of research would look into the relocation of large-acreage specialty crops to other areas of the state, should climate change issues ruin the current growing regions. This research could apply to temperature and flooding problems as well.
DeLaRosa said Safeguarding California will be reissued every three years with up-to-date analysis and prediction on climate change effects to various California sectors, as well as proposed action for adaptation.
As concerning as some of the climate change outlooks are, DeLaRosa said he’s optimistic.
“For climate change in general, it seems like right now there’s a lot of synergy,” he said. “I feel like there’s a lot there. It’s a positive story. We’re adapting.”
Staff Writer Brenna Swanston can be reached at bswanston@santamariasun.com.
This article appears in Mar 17-24, 2016.