Sign up for our daily briefing

Make your busy days simpler with Axios AM/PM. Catch up on what's new and why it matters in just 5 minutes.

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Catch up on the day's biggest business stories

Subscribe to Axios Closer for insights into the day’s business news and trends and why they matter

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Stay on top of the latest market trends

Subscribe to Axios Markets for the latest market trends and economic insights. Sign up for free.

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Sports news worthy of your time

Binge on the stats and stories that drive the sports world with Axios Sports. Sign up for free.

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Tech news worthy of your time

Get our smart take on technology from the Valley and D.C. with Axios Login. Sign up for free.

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Get the inside stories

Get an insider's guide to the new White House with Axios Sneak Peek. Sign up for free.

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Catch up on coronavirus stories and special reports, curated by Mike Allen everyday

Catch up on coronavirus stories and special reports, curated by Mike Allen everyday

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Want a daily digest of the top Denver news?

Get a daily digest of the most important stories affecting your hometown with Axios Denver

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Want a daily digest of the top Des Moines news?

Get a daily digest of the most important stories affecting your hometown with Axios Des Moines

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Want a daily digest of the top Twin Cities news?

Get a daily digest of the most important stories affecting your hometown with Axios Twin Cities

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Want a daily digest of the top Tampa Bay news?

Get a daily digest of the most important stories affecting your hometown with Axios Tampa Bay

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Want a daily digest of the top Charlotte news?

Get a daily digest of the most important stories affecting your hometown with Axios Charlotte

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Sign up for Axios NW Arkansas

Stay up-to-date on the most important and interesting stories affecting NW Arkansas, authored by local reporters

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

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

Miriam Kramer, author of Space
2 hours ago - Science

All-civilian Inspiration4 is back on Earth after flight to space

A side-by-side of the Inspiration4 crew and a shot of their capsule on the way back to Earth. Photo: SpaceX

The all-civilian Inspiration4 crew is back on Earth after their three-day mission in orbit.

The big picture: The launch and landing of this fully amateur, private space crew marks a changing of the guard from spaceflight being a largely government-led venture to being under the purview of private companies.

28 U.S. citizens depart Afghanistan on Qatar Airways flight

Passengers board a Qatar Airways aircraft bound to Qatar at the airport in Kabul on September 10, 2021. Photo: Aamir Qureshi/AFP via Getty Images

The State Department on Saturday confirmed that a Qatar Airways charter flight left Kabul on Friday with 28 U.S. citizens and seven lawful permanent residents on board.

The big picture: Friday's flight is the third such airlift by Qatar Airways since the Taliban takeover of Afghanistan, AP reports.

Updated 6 hours ago - Politics & Policy

Smaller than expected "Justice for J6" rally met with large police presence

Police officers watch as demonstrators gather for the "Justice for J6" rally in Washington, D.C., on Sept. 18, 2021. Photo: Andrew Caballero-Reynolds/AFP via Getty Images

A few hundred demonstrators were met by a heavy law enforcement presence on Saturday at the "Justice for J6" rally outside the fenced-off U.S. Capitol, AP reports.

The latest: Four people were arrested at the rally, including one person with a gun, one with a knife and two with outstanding warrants, per the U.S. Capitol Police.