Climate change will be deadlier and costlier for California than previously believed, state warns

Even if the sea rose 6.56 feet rather than the higher possible extreme now adopted by the state, more than 250,000 residents, $38 billion in property and 1,400 miles of roads along the coast are at risk of flooding during a severe storm in Southern California, according to a study led by the U.S. Geological Survey.

Climate change will be deadlier and costlier for California than previously believed, state warns

Heat waves will grow more severe and persistent, shortening the lives of thousands of Californians. Wildfires will burn more of the state’s forests. The ocean will rise higher and faster, exposing California to billions in damage along the coast.

These are some of the threats California will face from climate change in coming decades, according to a new statewide assessment released Monday by the California Natural Resources Agency.

The projections come as Californians contend with destructive wildfires, brutal heat spells and record ocean temperatures that scientists say have the fingerprints of global warming.

“This year has been kind of a harbinger of potential problems to come,” said Daniel Cayan, a climate researcher at the Scripps Institution of Oceanography and one of the scientists coordinating the report. “The number of extremes that we’ve seen is consistent with what model projections are pointing to, and they’re giving us an example of what we need to prepare for.”

State leaders vowed to act on the research, even as the Trump administration moves to unravel climate change regulations and allow more pollution from cars, trucks and coal-fired power plants.

“In California, facts and science still matter,” Gov. Jerry Brown said in a statement. “These findings are profoundly serious and will continue to guide us as we confront the apocalyptic threat of irreversible climate change.”

The state’s assessment draws on the latest science, including more than 40 new peer-reviewed studies, to project the effects of the continued rise in greenhouse gases on California’s weather, water, ecosystems and people and offer guidance on how officials across the state might adapt.

It’s the fourth such report since 2006, when Gov. Arnold Schwarzenegger ordered a climate change assessment as precursor to the Global Warming Solutions Act, the pioneering law California adopted that year to cut greenhouse gas emissions to 1990 levels.

This latest one for the first time scales down global climate models to project climate’s effect at the regional level or smaller. That approach is intended to provide local officials on the ground with more relevant, community-level information they can use to prepare.

“The difference between the San Joaquin Valley and the nearby coastal or Sierra Nevada mountains is enormous, so we have to have ways to unpack the large-scale global model calculations,” Cayan said.

Rising temperatures, deadlier heat waves

California has already warmed 1 to 2 degrees since the beginning of the 20th century as a result of the human-caused buildup of greenhouse gases. That figure could rise to between 5.6 degrees and 8.8 degrees by 2100, depending on the amount and rate of pollution spewed into the atmosphere, according to the report.

Those climbing temperatures could cause 6,700 to 11,300 more heat-related deaths annually in California by midcentury, the assessment found. Such fatalities will dominate economic damage to the state from climate change, costing up to $50 billion a year by midcentury.

Scientists have long projected more intense and longer-lasting heat waves by midcentury but have observed those changes occurring faster than anticipated.

“Something that used to happen every 10 years is happening every year,” said Rupa Basu, chief of air and epidemiology for the state’s Office of Environmental Health Hazard Assessment.

Reginaldo Ramirez gulps cold water after working in heat that reached 111 degrees in San Bernardino in August 2017. Heat waves will become more persistent, severe and health-threatening in California if greenhouse gas emissions continue to rise, the state's report warns.
Reginaldo Ramirez gulps cold water after working in heat that reached 111 degrees in San Bernardino in August 2017. Heat waves will become more persistent, severe and health-threatening in California if greenhouse gas emissions continue to rise, the state’s report warns. (Irfan Khan / Los Angeles Times)

Adding to the risks, scientists say, are trends toward higher humidity and warmer nights. Such conditions hinder people’s ability to recuperate and raise the likelihood of hospital and emergency room visits for a variety of illnesses, from heat stroke and dehydration to heart attacks, kidney disease, gastrointestinal illness and preterm births.

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The report also highlights shortcomings in how authorities classify heat waves and alert the public.

In one study cited in the assessment, researchers identified 19 heat waves that landed more than 11,000 people in the hospital between 1999 and 2000. The National Weather Service issued heat advisories for just six of the events.

That led researchers to devise a new way of identifying heat spells that may fall below established temperature thresholds but pose similar health risks. Such episodes, called heat-health events, are defined not by temperature readings but on the public health effects they cause at the local level, particularly to the elderly, young children and other populations most prone to falling ill or dying from the heat.

Modeling by researchers found those health-threatening heat spells will become a persistent fixture in summer months within a few decades, lasting two weeks longer on average in the Central Valley by midcentury.

More air conditioning could attenuate some of the harm, at least for those who can afford it.

Somewhat counterintuitively, researchers expect the health damage from higher temperatures to be worse in coastal areas with historically milder climates, where people are less acclimated to extreme heat and fewer have air conditioning. Researchers have found heat-related deaths to be less common in hotter, inland regions where more people have air conditioning units in their homes.

Seas rise higher than anticipated

As the ocean continues to warm, California’s coast will face more beach erosion, flooding and storm damage.

Until recently, scientists and state policymakers worked with a projection that sea level rise by the end of this century could amount to about 5.48 feet in California under the worst case scenario. But the latest reports and state policies are now accounting for the extreme possibility that sea level rise could exceed 9 feet.

These broader projections incorporate the potential rapid melting of the West Antarctic ice sheet.

Even if the sea rose 6.56 feet rather than the higher possible extreme now adopted by the state, more than 250,000 residents, $38 billion in property and 1,400 miles of roads along the coast are at risk of flooding during a severe storm in Southern California, according to a study led by the U.S. Geological Survey.

Among the most vulnerable communities:

  • San Diego, Coronado, Imperial Beach and National City in San Diego County
  • Huntington Beach, Seal Beach and Newport Beach in Orange County
  • Long Beach, Los Angeles and Malibu in Los Angeles County
  • Scientists modeled a 100-year flood — a severe but realistic storm that has a 1 in 100 chance of occurring in any given year this century — based on the latest climate science and sea level rise projections.
  • George Gonzalez, left, and Hector Maldonado, install a solar system on home in Van Nuys in 2016. Higher temperatures and more air conditioning will increase peak electricity demand, according to California's latest climate assessment.
    George Gonzalez, left, and Hector Maldonado, install a solar system on home in Van Nuys in 2016. Higher temperatures and more air conditioning will increase peak electricity demand, according to California’s latest climate assessment. (Irfan Khan / Los Angeles Times)

    More air conditioning will place added strain on the electrical grid by increasing peak demand. To avoid blackouts, utilities will have to make costly upgrades, such as additional generating capacity, substations and energy storage facilities, to meet demand during hot months.

    State energy officials said the assessment underscores the urgent need not only for swift global reductions in greenhouse gas emissions but also local actions to protect California from warming that’s already threatening people, natural resources and infrastructure.

    “We’re seeing that in the fire situation, we’re seeing that in sea level rise, we’re seeing that in heat spells, in declining snowpack,” said California Energy Commission Chairman Robert Weisenmiller. “The climate is changing now so we need to be adapting our communities.”

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