The year 2023 has been marked by extreme heat, with temperatures reaching unprecedented levels across the globe. According to a recent study, tree rings have revealed that 2023 was the hottest summer in the past 2,000 years. This finding is based on a new 1,200-year-long time series using tree rings, which shows that the current warming is unprecedented during this period.
Previous reconstructions of temperatures during the Medieval climate anomaly were based on the width or density of annual tree rings. However, these methods can be influenced by factors other than temperature, leading to inaccuracies in temperature reconstructions. The new study, published in the journal Nature, used a more precise method to extract temperature information from trees, focusing on cell wall thickness.
The new reconstruction, based on 50 million cells from 188 living and dead Scots pines in Sweden and Finland, shows that the Medieval climate anomaly was cooler than previously thought, at least in Scandinavia. This finding aligns with climate model simulations, providing new evidence that the current warming is outside the range of natural fluctuations in temperatures over the past 1,200 years.