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The remains of a destroyed car stand infront of a destroyed home in the aftermath of the Holiday Fire on July 7, 2018 in Goleta, California. Credit: Mario Tama/Getty Images

Southern California's intense heat wave, which has shattered dozens of temperature milestones, including all-time records, is exactly the kind of event that is becoming more likely and severe due to global warming, scientists told Axios.

Why this matters: The heat wave has sparked destructive wildfires and threatened public health for millions of Californians, and is a stark reminder that even a small amount of global warming can push climate extremes into new and far more dangerous territory.

By the numbers

Consider some of the records that have been set so far during what now ranks as one of Southern California's all-time hottest heat waves.

  • 82° Fahrenheit: Hottest all-time overnight low temperature on record for any month in Burbank, California.
  • 79°F: Hottest overnight low temperature on record for the month of July in L.A. on July 7.
  • 111° F: Hottest daytime high temperature ever recorded at the UCLA weather station in Los Angeles, set on July 6. This beat the old record of 109°F, set in 1939.
  • 114°F: Hottest all-time temperature on record at Burbank Airport, recorded on July 6.
  • 120° F: Highest temperature — set in Chino on July 6 — ever recorded by any automated weather station in the valleys or coastal areas around Orange, Riverside, San Bernardino and San Diego Counties.

The big picture: This event occurred months earlier than usual, and still set all-time records. California's hottest time of year tends to be in the early fall, when dry, down-sloping winds, known as the Santa Ana, blow from east to west, compressing and heating up the air as it flows into Los Angeles and San Diego.

Computer model simulation showing extremely hot temperatures in southern California on July 6, 2018.
What they're saying

Climate scientists told Axios that global climate change is a significant factor behind the heat event, even though it's not the proximate cause.

  • Stanford University climate scientist Noah Diffenbaugh has published studies showing how a relatively small shift in the global average surface temperature of just 1° Celsius, or about 1.8°F, in the past century has dramatically upped the odds of severe heat events.
“When we look around the world at record hot events we find there’s already a human fingerprint at 80% of the events where we have observational records.”
— Diffenbaugh
  • Daniel Swain, a climate scientist at UCLA, noted that there has not yet been a formal study on the connection between this heat wave and climate change, since that could take a few weeks to complete. Such studies are known as "climate attribution" research. However, the climate change link to this event is already evident, he said.
“The reality is when it comes to heatwaves now there’s almost always a human fingerprint. One of the clearest consequences of global warming is more heat, higher temperatures.”
— Daniel Swain, climate scientist at UCLA
The bottom line

Michael Wehner of Lawrence Berkeley National Laboratory, who is working to conduct extreme event attribution studies in advance of an event, told Axios via email, that "[i]n probabilistic terms, climate change increased the chances of the heat wave by about 20 to 50 times," adding that there is at least a 99% likelihood that human-induced climate change "increased the severity of this heat wave."

Go deeper

Updated 45 mins ago - World

Biden cleans up comments about Russia invading Ukraine

Photo: Doug Mills-Pool/Getty Images

President Biden sought to clarify his suggestion that a "minor incursion" by Russia into Ukraine may not draw the same response as a large invasion, telling reporters Thursday that "Russia will pay a heavy price" if any troops cross the border.

Why it matters: Some officials in Kyiv saw Biden's comments as inviting Russian aggression.

Tina Reed, author of Vitals
58 mins ago - Health

Study finds bias against Black patients written into medical charts

Illustration: Sarah Grillo/Axios

Black patients were more than two-and-a-half times as likely as white patients to have negative descriptors about them in their electronic health record, according to a study published Wednesday in Health Affairs.

Why it matters: The study is further evidence of bias in the U.S. health care system, which can ultimately result in worse care and disparately poor outcomes.

Jan. 6 panel asks Ivanka Trump to cooperate with investigation

Former President Trump and daughter Ivanka Trump walk to Marine One on the South Lawn of the White House on January 4, 2020 in Washington, DC. Photo: Drew Angerer/Getty Images

The House select committee investigating the Jan. 6 Capitol riot sent a letter Thursday to Ivanka Trump requesting her cooperation with the investigation.

Driving the news: "We write to request your voluntary cooperation with our investigation on a range of critical topics," the chair wrote in a letter to the former president's daughter.