September Broke Heat Records ‘By Large Margin,’ Experts Say

Updated October 5, 2023, 3:00 p.m. EST

• Last month was the hottest September ever recorded, scientists report. Climate experts said they are in disbelief by the heat. 
• The European Union's Copernicus Climate Change Service emphasized the concerning string of record-breaking monthly temperatures, as this was the hottest summer "by a large margin."
• September was the most anomalously hot month on record, meaning its deviation from the average was higher than any previous month. Temperatures were almost a full degree hotter than Sept. 2020, which had the previous record. 
• Samantha Burgess, deputy director of the Copernicus Climate Service, said:

"Normally when you're beating a record, it's by hundredths of a degree...so this is really a huge amount."

• Zeke Hausfather, climate researcher lead for financial service company Stripe, said on X:

"This month was, in my professional opinion as a climate scientist - absolutely gobsmackingly bananas."

Updated July 28, 2023, 1:30 p.m. PST

• According to scientists, July is not only the hottest month since record-keeping began but is most likely the hottest month in over 120,000 years.
• U.N. Secretary-General António Guterres has said we are now in the "age of global boiling." He continued:

“Climate change is here. It is terrifying. And it is just the beginning. It is still possible to limit global temperature rise to 1.5 C [above pre-industrial levels] and avoid the very worst of climate change. But only with dramatic, immediate climate action.”

• Ocean temperatures are also at record levels, and in mid-May, ocean temperatures reached unprecedented levels for that time of year.
• Samantha Burgess, from the European Union’s Copernicus Climate Change Service, said, “These are the hottest temperatures in human history."
• Burgess continued:

“We are seven months into 2023, and almost every month this year has been in the top five hottest on record.” 

• A new report has found that the heat waves in the U.S. and Europe would have been "virtually impossible" without climate change.
• Kim Cobb, a climate scientist at Brown University, said: 

“It is scary to remember that in another decade, this will be viewed as a relatively cool year, most likely. If people don’t like what they’re seeing this summer, they will be in for quite a shock at the higher warming levels we’re heading for.”

• Guterres said:

“For the entire planet, it is a disaster. Short of a mini-Ice Age over the next days, July 2023 will shatter records across the board.”

What's the story?

• This week, Earth experienced the hottest days ever recorded in modern history. 
• Scientists reported that a blistering heatwave blanketed regions ranging from North America to Antarctica. Forecasters warn that a multiyear period of exceptional warmth may be approaching, driven by greenhouse gas emissions and the return of El Niño.

The summer so far

• On Tuesday, the global average climbed to the highest temperatures since the records began in the 1940s, according to the European Union's Copernicus Climate Change Service. 

According to preliminary data from the #ERA5 dataset, the daily global average 2m #temperature reached 17.03°C on Tuesday, setting a new record.

Get the data 👉https://t.co/V3rirrGxRD pic.twitter.com/JsSyva9skY

— Copernicus ECMWF (@CopernicusECMWF) July 6, 2023

• This past June was the warmest ever recorded, with deadly high temperatures in Mexico and the southern U.S. Brian McNoldy, senior research scientist at the University of Miami, said: 

"It's so far out of line of what's been observed that it's hard to wrap your head around. It doesn't seem real."

The big picture

• While scientists are concerned, many are unsurprised by this week's numbers. Climate scientist at Berkeley Earth, Dr. Zeke Hausfather, said the temperatures are "well within the realm" of what scientists feared could be a new reality.
• Earth's average temperatures have increased nearly 2 degrees Fahrenheit since the 19th century and show no sign of slowing. The next few years will show an even more intense temperature growth because of the El Niño event. 
• Scientists are especially nervous about El Niño's impacts on ocean life. This April, the global sea surface reached a new record high temperature, increasing quicker than ever before and baffling scientists. Experts worry that the temperature could reach a concerning level by the end of next year. Hausfather said:

"A big reason we're seeing so many records shattered is that we're transitioning out of an unusually long three-year La Niña, which suppressed temperatures, and into a strong El Niño." 

How do you feel about these record-breaking temperatures?

-Jamie Epstein

(Photo credit: iStock/Marc Bruxelle)