Climate Crisis

September Air Temperature Data Leave Scientists ‘Gobsmacked’


A couple of weeks ago ecoRI News reported that the sea surface temperature for September was above record highs. Now comes the release of the world’s air temperature data, which is even more alarming.

Climate scientist Zeke Hausfather called the September warming “absolutely gobsmackingly bananas.”

Hausfather is the climate research lead for the financial services company Stripe. His comment appeared on X, formerly known as Twitter, and has since been quoted widely.

Hausfather was not the only one commenting on September’s temperatures, which have climate scientists stunned.

“September temperatures have broken records by an extraordinary amount,” said Samantha Burgess, deputy director of the European Union’s Copernicus Climate Change Service.

“It’s just mind-blowing, really,” added Copernicus director Carlo Buontempo. “Never seen anything like that in any month in our records.”

The chart below shows why scientists are concerned.

The worldwide air temperature anomalies for September from 1940 through 2023. The value for September 2023 is shockingly high. (Chart by Roger Warburton, data from Copernicus)

No matter how you look at it, the temperature anomaly for September stands out. Most scientists expected the anomaly to be around 0.5, which would have been a significant increase.

The anomaly value of 0.9 degrees Centigrade (1.7 degrees Fahrenheit) surprised everyone.

New England did not escape the record temperatures.

The temperatures across New England were shockingly high for September.
(Chart by Roger Warburton, data from Copernicus)

The chart below shows the average worldwide monthly temperature from 1940 through 2023. This chart also shows the huge surge in temperature for summer 2023.

The monthly average worldwide air temperatures from 1940 through 2023. The increase in temperature for summer 2023 is dramatic. (Chart by Roger Warburton, data from Copernicus)

This year is on track to become the hottest on record.

Annual average temperatures this year are expected to end up about 1.4 degrees Celsius (2.5 degrees Fahrenheit) above preindustrial levels. That would be closer than ever to the feared benchmark of 1.5 degrees of warming above preindustrial levels.

Perhaps Hausfather’s description of the September temperature as “absolutely gobsmackingly bananas” is an appropriate response.

Roger Warburton, Ph.D., is a Newport resident. He can be reached at [email protected].


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  1. Much appreciate today’s “September Air Temperatures” and previous articles by Roger Warburton. Besides his straightforward analyses of key patterns, wonderful examples of how to write in clear, compact manner.

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