Not only was last summer harsh, but it was also unusually hot. According to a recent analysis, the Northern Hemisphere’s summer of 2023 was the warmest in the previous 2,000 years. A natural climate database called tree rings was used by researchers to compare temperatures over millennia.
According to research that was published in Nature, 2023 surpassed 2016 as the previous record-holder by 0.15 degrees Celsius. More importantly, it was at least 0.5 degrees Celsius hotter than the hottest summer prior to human-caused warming.
“The trees tell us that 2023 was exceptionally warm,” said study co-author Jan Esper, a climate scientist.
The urgency to combat climate change is heightened by these discoveries. While not unexpected, the extreme temperatures highlight the long-term warming trend and its consequences.
Tree rings offer a deeper look into the past than traditional temperature measurements, which only go back about 100 years. These annual growth rings reflect seasonal temperatures, allowing scientists to reconstruct past climates.
The analysis focused on the Northern Hemisphere between 30 and 90 degrees north latitude due to limitations in tree ring data from other regions.
The research confirms 2023 surpassed all summers in the past 2 millennia. It was at least 0.5 degrees Celsius hotter than the previous hottest summer (246 AD) and a staggering 3.93 degrees Celsius warmer than the coldest (536 AD).
“It’s pretty impressive that you can go 2,000 years back and know that we’re hotter than any of those individual years,” said Vikki Thompson, a climate scientist not involved in the study.
While 2023 might not be a singular jump in warming, it reflects a concerning trend. The study underscores the need for drastic reductions in greenhouse gas emissions and a shift away from fossil fuels.
Esper acknowledges the challenge: “The latest numbers are not promising at all.” However, he sees signs of change and hopes the findings will spur action.
His research continues – he aims to gather more tree ring data, including from the US. Expanding this paleoclimate record is crucial for understanding the past and informing future climate action.
“We want to protect the trees,” Esper concludes, highlighting the interconnectedness of climate change and environmental preservation.