PICTURED: Photo of the Thomas Fire taken on Dec. 9, 2017. Photo by Kari Greer for the U.S. Forest Service

In 2017, during a record “red flag” wind event in December, the Thomas Fire burned from Santa Paula westward into Ventura and northward around Ojai into Santa Barbara County, killing one county resident and a firefighter, totaling over $2 billion in property damages and costing over $200 million to fight.

In November 2018, during a “red flag” wind event, the Woolsey Fire burned from the Santa Susanna Mountains above Simi Valley all the way to the ocean, killing three people in Malibu, destroying over 1,000 homes and forcing the evacuation of well over 200,000 people.

On Oct. 30 of this year, an “extreme red flag warning” wind event drove the Easy Fire from the Simi Valley mountains toward the Ronald Reagan Library. Two days later, high winds drove the Maria Fire from an overlooking ridge down toward Santa Paula, Somis and Saticoy.

Ventura County’s climate is changing. To better understand what it will look like in the near future, two researchers for the Desert Research Institute (DRI), under a grant administered by the Ojai Valley Land Conservancy in 2018 and using an ensemble of 32 climate models, projected our future climate for the years 2020-40.

What does our climate in Ventura County look like in the next 20 years?

The report, “Projected Changes in Ventura County Climate,” stresses that higher temperatures will heighten the risk of wildfire.

“Wildfire season will likely extend earlier into the spring and early summer and later into the fall and early winter,” states the executive summary, “due to drying in these seasons, increased temperature, and greater evaporative demand.”

The blue line shows average temperatures from December 2017 through November 2018. Note the spike in temperature for the month of December (when the Thomas Fire broke out) — 8 degrees above normal. Another spike in July 2018 coincides with the heat waves that led to avocado damage across the county. Source: California Climate Tracker, Desert Research Institute, Western Regional Climate Center

All of those conditions were on hand when the Thomas Fire broke out in December of 2017. Winds as fast as 60 mph were recorded in the local mountains. Because the county had seen below-average rainfall for most of the decade, levels of fuel moisture in hillside plants were extremely low — less than 10 percent. The average temperature in the county was nearly 8 degrees above normal for the entire month of December [See graphic, “South Coast (Climate Region)”]

“Already our wildfire season extends earlier in the spring and later into the fall,” said Mark Jackson, meteorologist in charge of the National Weather Service office in Oxnard. “There’s a domino effect that happens with longer fire seasons.” As moisture is transpired by plants out of the soil, he explained, the ability of the land to cool lessens, amplifying the heating.

For Devon Davis, an amateur meteorologist based in Camarillo who mans the @805weather Twitter feed focused on Ventura County, the first result that stood out from the DRI study was “an increase in drying winds associated with Santa Ana wind events.” He noted the Thomas Fire as an example of such a wind-driven fire.

“The fact is that now there’s an increased likelihood of wind-driven wildfires,” he said. “The study is kind of a real-time look into the near future.”

More Fire, Hotter Temperatures

Heat waves will also become more common and much more extreme in the years 2021-40 in Ventura County. The average temperature in the county will increase by “at least 3-5 degrees Fahrenheit” in the next 20 years in inland and elevated areas of the county, such as Ojai, Thousand Oaks and Simi Valley. Coastal areas such as Ventura and Oxnard will see average annual temperatures increase by “at least 2-3 degrees.”

Red Flag wind warnings for critical fire weather conditions, as reported on Wednesday, Oct. 30, in Ventura and Los Angeles counties by the National Weather Service on Twitter (@NWSLosAngeles). Larger circles indicate stronger winds. The Easy Fire started that morning in Simi Valley, while the Maria Fire started in Santa Paula the following day. Source: National Weather Service Los Angeles

Lead author Ben Hatchett warns that although temperatures along the coast will still be cooler than inland areas at higher elevations, the additional warming may surprise coastal residents.

“If you live in Ventura, you know that it’s rare that temperatures hit 90 degrees,” Hatchett said. “But whatever the hottest temperature you have experienced in Ventura, this study says that you will have about two more weeks of that kind of heat annually in Ventura. People without air conditioning may feel like they’re getting cooked with an extra week or two of extremely hot temperatures.”

Brian Brennan, former member of the Ventura City Council who now serves on the executive board of the Casitas Municipal Water District, recalls the heat wave of July 6, 2018, when temperatures reached as high as 117 in Ojai, scorching fruiting avocado branches around the county.

“It was 97 degrees at 9:30 that night,” Brennan recalled. “We’re not equipped with air conditioning. I said: I’m going to sleep on the beach tonight.”

Mark Jackson, the meteorologist, said that this study fits well with the larger studies he’s seen on a changing climate.

“Global temperatures have increased by about two degrees in the last fifty years,” he said. “That’s an average. But what really has to be driven home to people is that it’s not the average temperature increase that matters most. People may hear that it’ll increase three degrees in the next 50 years, and they imagine that means the temperature goes from 75 to 78. But that’s not how it works. It’s the increase in the extremes — hot days and warm nights — that matters. It’s the increase in the number of heat waves, and the number of droughts.”

Heat waves in Southern California have been on the rise, but vary greatly year to year. By contrast, the minimum daily temperatures in the county have been increasing slowly but steadily as the amount of greenhouse gases in the atmosphere accumulate. That’s no coincidence, Hatchett said.

“Greenhouse gases prevent radiation [in the form of heat] from escaping,” he said. “At night time we should be losing energy to space. With more water vapor and other greenhouse gases in the atmosphere, the outgoing longwave radiation is trapped.”

Hot temperatures at night are substantially new to Southern California, as both the DRI report and other studies show. Before 1970, night time heat waves in California were almost unheard of. In recent years, they have become more common than daytime heat waves. (See chart, “Statewide trends in heat waves.”)

Before 1970, nighttime heat waves were virtually nonexistent in California. Starting in the 1980s, they’ve become more common than daytime heat waves. According to Ben Hatchett of the Desert Research Institute, the increase of greenhouse gases in the atmosphere is preventing radiation in the form of heat from escaping at night. Source: “2018 Report: Indicators of Climate Change in California,” by the California Office of Environmental Health Hazard Assessment

“The greatest increase in the total number of daytime and nighttime extreme heat events occurred in Southern California,” according to the 2018 California Office of Environmental Health Hazard Assessment, “Indicators of Climate Change in California.” “For most regions, the rate of increase in the number of extreme heat nights was twice that of the rate of increase in extreme heat days.”

Consequences of Extreme Heat

“This is the challenge we face,” said Jackson. “People can see tornadoes and hurricanes. But this warming is happening slowly, so we don’t realize the risk.”

Bill Patzert, a climatologist long associated with the NASA-affiliated Jet Propulsion Lab in Pasadena, puts it more bluntly.

“Of all the natural disasters, by far the most deadly are heat waves. In 2003, a heat wave hit southern Europe. Mostly the climate there is moderate, and people didn’t have air conditioning, or if they did have it they were old and couldn’t afford to turn it on,” he said. “About 70,000 people died. Look it up if you don’t believe me. It’s an urban phenomenon, rather than a rural thing, because of the urban heat island effect.”

Statistics from California also verify his statement. In 2006 a July heat wave enveloped virtually the entire state of California, and in terms of human health caused far more destruction than the Northridge earthquake of 1994, the Loma Prieta earthquake of l989, the North Bay Fires of 2017 or even the Camp Fire that destroyed the town of Paradise, the deadliest fire in state history. 

None of those disasters killed 100 people. The now-forgotten 2006 heat wave, however, killed more than 600 people, resulted in over 16,000 visits to the ER and 1,200 hospitalizations, and cost over $5 billion, according to the public health chapter of California’s fourth climate assessment.

The National Weather Service has found that ER visits increase above 95 degrees, and that temperatures above 104 lead to an “exponential increase” in the risk of mortality.

Outdoor workers and farmworkers are especially at risk from climate change. Lucas Zucker, a policy advocate with CAUSE, the Central Coast Alliance for a Sustainable Economy, said that the state of California had put in protections for farmworkers working in temperatures above 95 degrees, such as requiring breaks every two hours, with cool water and shade. His organization appreciates these efforts, but thinks county officials could do more to enforce the regulations.

Temperature chart showing the steady rise in average temperature during the month of August from 1950 to 2019 in California’s South Coast region, which includes Ventura, Los Angeles, Orange and San Diego counties. Source: National Oceanic and Atmospheric Administration

“Too often with climate change the focus is on celebrities in places like Malibu, and what we’re going to do when their beachfront homes are underwater,” he said. “Those celebrities might have to relocate inland, but they’re going to be fine. It’s harder for people to wrap their heads around the vulnerability of farmworkers. They’re not only on the front lines of climate change through their livelihoods, but also because they don’t have the economic power to survive extended layoffs we’ve seen due to drought or heat waves or storms, or even smoke from wildfires.”

What About Rain?

The study noted the record-breaking drought this decade, but did not find in the modeling a clear indication that the county would see either more or less rain in the next 20 years. But with more heat and about 10 percent more evapotranspiration from plants in the county, the report warned of increased susceptibility to drought.

Patzert, who has done his own trend analysis of precipitation in the state, finding little change in the amount of rain and snow over the last century, questioned the usefulness of a county analysis that didn’t look at aquifer levels.

“The draining of the aquifers in the county is a hundred times more important than finding out if we have a trend of an inch or two less in rainfall,” he said. “Southern California imports 70 percent of its water. Who cares what the trend in precipitation is this year in the county? It’s the wrong question.”

About three out of four people in Ventura County rely on state water imported from Northern California, distributed through the Calleguas Municipal Water District headquartered in Thousand Oaks. But West County, including the Ojai Valley and West Ventura, still depends on local rainfall, which is collected in aquifers and at the Casitas reservoir, and managed by the Casitas board of directors.

Newly elected member of the board Brian Brennan said that Casitas is investigating several options for new sources of water, including drilling deep into aquifers, and looking into a connection to the state water project along the coast near Carpinteria.

“Around the state this year, water districts were practically paying people to take their water, dumping it out of reservoirs [to make room for spring run-off],” he said. “We have excess storage capacity at Lake Casitas. We need to take advantage of those times such as with atmospheric rivers when we’re getting a lot of rain.”

“Climate Emergency”

Members of Extinction Rebellion Ojai on July 22, after the Ojai City Council voted to declare a “climate emergency.” Photo by Kit Stolz

Some of the hottest temperatures recorded in Ventura County have been recorded in Ojai. Environmental leaders were alarmed by news from the county climate report that inland areas such as Ojai will likely experience an additional 20 days a year of extremely hot temperatures.

Melanie Larkins, the executive director of the Ojai Valley Green Coalition (OVGC), saw the report presented at a workshop at the county government center in February.

“To have climatologists present real numbers backed by science for our valley and our area, and see where we are headed, it was a little shocking to me,” she said. ‘To be honest it was pretty bleak.”

Members of the OVGC worked with Ojai City Council, which by a split vote approved the declaration of a “climate emergency” for the town on July 22. This is intended to encourage actions to reduce emissions and conserve water.

Will these sort of changes be enough?

“This is not global warming anymore,” warned Patzert. “This is global heating.”

RESOURCES

 “Projected Changes in Ventura County Climate”: wrcc.dri.edu/Climate/reports.php

“Indicators of Climate Change in California”: oehha.ca.gov/climate-change/report/2018-report-indicators-climate-change-california

Central Coast Alliance United for A Sustainable Economy (CAUSE): causenow.org

Ojai Valley Green Coalition: ojaivalleygreencoalition.org