Of all the heat records broken this year — and there have been many — the one that September just notched might be the most absurd. 

Last month was the hottest September on record by 0.5 degrees Celsius (0.9 degrees Fahrenheit). That may not sound like a big deal, but as far as heat-record margins go, it’s massive — or, as climate scientist Zeke Hausfather posted on the social networking site known as X, “absolutely gobsmackingly bananas.” 

“We’ve never seen a record smashed by anything close to this margin,” Hausfather told Axios. “It’s frankly a bit scary.”

September’s average global temperature was 0.9 degrees C higher than the recent historical average and 1.8 degrees C above pre-industrial levels. The month’s mercury measurements — which come from the Japan Meteorological Agency and Europe’s Copernicus Climate Change Service — were more fitting for midsummer. Though summer isn’t what it used to be either: July was the hottest month in 120,000 years, with the hottest week and day ever recorded, all during the hottest summer known to humankind. 

While scientists say climate change, fueled by the combustion of fossil fuels, is to blame for the planet’s long-term warming trend, this year’s gobsmacking record smashing got a nudge from a cooling La Niña weather pattern giving way to a strong El Niño in the Pacific Ocean, which formed over the summer. El Niño typically has a stronger warming effect in its second year and could ascend to ‘super’-status levels by winter, according to a recent experimental forecast by scientists at the National Center for Atmospheric Research. 

Even though this year’s warming is consistent with predictions, the September record still came as a shock to some researchers. “I’m still struggling to comprehend how a single year can jump so much compared to previous years,” Mika Rantanen, a climate researcher at the Finnish Meteorological Institute, posted on X. 

September’s unmatched heat showed up with near-100-degree weather in the eastern United States and Europe and a freakishly warm end to winter in South America, where highs hit 110 degrees F. Much of Europe was still sweltering under unseasonable heat at the start of October. 

At the bottom of the planet, the extent of winter sea ice in Antarctica hit an all-time low — 1 million square kilometers less ice than the previous record, set in 1986.

“It’s not just a record-breaking year, it’s an extreme record-breaking year,” Walt Meier, a senior scientist at the National Snow and Ice Data Center, told Reuters.

The searingly hot temperatures have, at least temporarily, put the planet beyond the 1.5 degrees C rise in warming that global leaders had pledged to avoid as part of the Paris Agreement. But what matters most, scientists say, is keeping the planet from sustaining that level of warming over many years. Luckily, that’s still possible, the International Energy Agency recently announced. To succeed, countries will need to triple renewable energy capacity and double energy efficiency improvements by 2030, according to the IEA. Demand for climate-warming fossil fuels is expected to peak this decade.

This story was originally published by Grist with the headline Earth just set another heat record — by the largest margin yet on Oct 4, 2023.