Confirmed: the summer of 2023 was the hottest in the last 2,000 years

“2,000 years?” I hear you say! How can they know when records only go back to 1850?

Well, the answer to that is that scientists have turned to tree rings to fill lack of instrumental records and discover a magnitude of ongoing warming.

Scientists from the University of Cambridge and the Johannes Gutenberg University in Mainz have thus demonstrated how exceptional the summer of 2023 was.

Even allowing for natural climate variations that can occur over hundreds of years, 2023 was the hottest summer since the height of the Roman Empire, exceeding the extremes of natural climate variability by half a degree Celsius.

The earliest instrumental temperature records, from 1850 to 1900, are sparse and inconsistent. So the researchers compared the early instrumental data with a large-scale tree-ring data set and found that the 19th century reference temperature used to contextualize global warming is several tenths of a degree Celsius cooler than previously thought.

By recalibrating this baseline, the researchers calculated that 2023 summer conditions in the Northern Hemisphere were 2.07°C warmer than the average summer temperatures between 1850 and 1900.

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