The global average temperature for September broke records by such an absurd margin that climate experts are struggling to describe the phenomenon. From a report: “This month was — in my professional opinion as a climate scientist — absolutely gobsmackingly bananas,” Zeke Hausfather, a researcher with Berkeley Earth, said on the social media platforms Bluesky and X. The numbers are stark. September 2023 beat the previous record for the month, set in 2020, by 0.5C (0.9F), according to data sets maintained by the Japan Meteorological Agency and the EU’s Copernicus Climate Change Service. The temperature anomaly for the month was roughly 1.7C above pre-industrial levels, which is above the symbolic 1.5C mark set as the stretch goal in the Paris Agreement.
“We’ve never really seen a jump anything quite of this magnitude,” Hausfather said. “Half a degree C is analogous to slightly less than half of all the warming we’ve seen from pre-industrial [temperatures].” Carbon dioxide emissions from burning fossil fuels are the main driver of rising temperatures. The global average temperature this year has also seen a boost from El Nino, a natural climate shift in the Pacific. Other factors may also be pushing temperatures up incrementally, such as a decline in cooling aerosol pollution from ships. Hausfather said next September may be unlikely to have all the same compounding factors, and consequently may be not as extreme. But either way, he described September 2023 as a “sneak peek” of what the back-to-school month may feel like in a decade as climate change pushes temperatures higher.