Summer 2023 eclipses Roman Empire's warmth, rings alarm bells

Last year's summer in the Northern Hemisphere was the hottest in recorded history. It's worth noting these records have been maintained since the mid-19th century. Surprisingly, the summer months 2023 marked the hottest period since records began! Scientists have established this by examining tree rings, indicating it was even warmer than during the Roman Empire.

There's a consensus among scientists that our planet's temperature is on a consistent upward trajectory. Since the industrial revolution, the average global temperature has increased by about 1 degree Celsius. Some climate change sceptics argue that since temperature records only started in 1850, it's challenging to make definitive conclusions. Despite the relatively short history of recorded measurements, scientists have developed methods to ascertain temperature data going back to the dawn of our era.

This is possible thanks to dendrochronology, or the study of tree rings, which provides insights into past climatic conditions. In an article published in "Nature", scientists from Germany and the UK highlighted that dendrochronological findings offer crucial information about historical temperatures and moisture levels.

Research conducted by the University of Cambridge in the UK and Johannes Gutenberg University Mainz in Germany has shown that the summer of 2023 was remarkable. National Geographic said it was "the hottest summer since Roman Empire times."

When you look at the long sweep of history, you can see just how dramatic recent global warming is. 2023 was an exceptionally hot year, and this trend will continue unless we reduce greenhouse gas emissions dramatically, says Prof. Ulf Büntgen from the Department of Geography at the University of Cambridge, a co-author of the study.

While the accuracy of 19th-century measuring tools might be questionable, the data derived from dendrochronology is exact. Trees have a unique response to varying conditions.

Scientific analyses reveal two minor ice ages within the last 2,000 years. The first happened around the 6th century AD, and the second at the start of the 19th century, both triggered by sulfur-rich volcanic eruptions. Following one such eruption, the coldest summer of our era was documented in 536 AD, with temperatures approximately 4 degrees Celsius cooler than in the summer of 2023.

A comparison of average temperatures over the past two millennia shows that last year's summer months were, on average, 2.2 degrees Celsius warmer than the mean temperature from the 1st century to the end of the 19th century. The research underscores the potential for breaking new temperature records this summer, posing a challenging situation.