‘Extreme Heat’ forecast provides California temperature projections for mid- and late-century
We think we know hot.
But imagine temperatures surpassing 100 degrees 30, 40, even 50 days a year, or adapting to a climate where one day out of every three is above 90.
Wine Country will fare far better than Central and Southern California, but the face of the not-too-distant future has a sunburn and a sweaty brow, according to a recent forecast of community conditions around California.
A new online tool introduced earlier this month allows users to see what climate models say about their own county, community, ZIP code, census tract, even their neighborhood — down to their street address.
Sonoma tops the list of Sonoma County’s hottest cities, with the potential for 39 days a year at 100 degrees by late century, defined as the year 2070-2099 by the California Healthy Places Index: Extreme Heat Edition.
But by midcentury — 2035 to ‘64 — residents there will be looking at 23 days a year above 100 degrees and 90 days above 90 degrees.
Cities in neighboring counties — Ukiah, Calistoga, Lakeport and Clearlake — are projected to have even more extreme heat, raising greater concerns not just about sheer discomfort but about public health and safety.
“I don’t think people realize that extreme heat is actually the number one killer of any extreme weather” — more than hurricanes, more than flooding, more than wildfires, said John “Jake” Dialesandro, a postdoctoral research fellow at the UCLA Luskin Center for Innovation who focuses on climate science. “People don’t really think about the consequences of heat.”
No recovery time
Circumstances around the globe are increasingly forcing us to do just that, however, with staggeringly high, deadly temperatures in India and Pakistan this year, record highs in China, blazing conditions across Europe (which melted and buckled asphalt roads and runways in Britain), and oppressive heat affecting tens of millions of Americans across much of the country this past week.
“What we’re seeing is not just hotter days,” said Sonoma County Director of Emergency Management Chris Godley. “The real concern is that the heat’s not going to go away at night. The temperatures don’t dip, which is what is called the recovery phase.”
Scientists also are exploring changes in sea breezes and the degree to which ocean fog is less likely to extend over the land, providing less of what Godley described as that “Bodega Bay air conditioning” that tends to cool inland Sonoma County down at night.
The combination would mean people exposed to extreme heat over multiple days would more likely suffer health problems such as heat exhaustion or heat stroke without focused adaptation and precautions.
There are also complicating factors that make extreme heat dangerous, particularly for the young and the old, those already suffering from preexisting illness, outdoor workers, pregnant people, the homeless and those in confined, non-air conditioned settings.
Heat can compound existing health conditions in some people or exacerbate adverse atmospheric or environmental conditions, such as low-level particulate matter, Godley said.
Vectors, like insects and other animals, also may alter their range as traditional habitats become unsuitable, bringing disease-causing organisms to new areas.
“The way I think about heat is through the lens of hazard assessment,” Godley said.
And though concerted efforts are under way around much of the globe to substantially draw down carbon emissions, the human race already has ensured temperatures will rise for several decades through emissions already accumulated.
“The book’s already closed on that,” Dialesandro said, “so mitigation is our number one priority right now.”
Projecting the upper limits
The California Healthy Places Index: Extreme Heat Edition is the latest effort to project the upper limits in California — and prod users to prepare for it. It is the product of a partnership between the UCLA Luskin Center and the Public Health Alliance of Southern California, a coalition of 10 local health departments in Southern California representing more than 60% of the state population.
The first version of the Healthy Places Index, launched in 2018, offered a public platform overlaying demographic, economic, environmental, health and other data to inform policymakers and advance health equity in California.
The Extreme Heat Edition, introduced in July, adds in projected heat exposure as well as place-based information on factors like tree canopy coverage, resilient housing, heat-island impacts and access to parks. Additional information includes data on the degree to which the population is vulnerable due to age, medical condition, economics or other reasons.