Tree rings show summer 2023 was warmest since year 1

The scorching summer of 2023 has been the warmest in the Northern Hemisphere in more than 2,000 yearsaccording to the findings of a new study.

When temperatures soared to their highest levels last year, numerous meteorological agencies indicated that it was the warmest month, summer and year on record. However, this record only dates back to 1850. at most, because it is based on the use of the thermometer. Now, scientists can go back to year one of the Western calendar, when, according to the Bible, Jesus Christ walked the Earth, but found no other summer warmer than last year.

In A study published Tuesday in the journal Nature used a well-established method and records from more than 10,000 tree rings to calculate summer temperatures each year, starting in year one.. No year even came close to the high temperatures of last summer, said study lead author Jan Esper, a climate geographer at the Gutenberg Research College in Germany.

Before humanity began emitting heat-trapping gases into the atmosphere by burning coal, oil, and natural gas, the warmest year was 246Esper noted. That was at the beginning of the medieval era of history, when the Roman emperor Philip the Arab fought the Germans on the Danube River.

Esper's research shows that, In the Northern Hemisphere, the summer of 2023 was 2.1 degrees Fahrenheit warmer than the summer of 246. In fact, 25 of the last 28 years have been warmer than said medieval summer, said Max Torbenson, co-author of the study.

That gives us a good idea of ​​how extreme 2023 was.″Esper told The Associated Press.

The team used thousands of trees from 15 different sites in the northern hemisphere, north of the tropics, where there was enough data to get a good number up to year one, Esper said. Not enough data was obtained from trees in the southern hemisphere to be publishedbut the little data showed something similar, he said.

Scientists analyze the annual growth rings of trees and “we can put them together like a puzzle back in time, so we can assign annual dates to each ring,” Torbenson said.