In a groundbreaking discovery, scientists have found that the summer of 2023 was the hottest in the Northern Hemisphere since year 1. The study, published in the journal Nature, examines historical temperatures dated back beyond 1850 using tree ring data.
Cambridge Department of Geography Professor Ulf Büntgen and his team at the University of Cambridge and Johannes Gutenberg University Mainz in Germany used tree ring data to compare summer temperatures going back over two millennia. The research team examined more than 10,000 tree rings in order to calculate historical global temperaturesThey determined that last year’s summer was significantly hotter than any other recorded, confirming the increasing alarm around global warming.
The Northern Hemisphere has already surpassed the temperature threshold agreed upon in the 2015 Paris Agreement on climate change, according to the study. This international pact aims to limit warming to no more than 2 degrees Celsius above pre-industrial levels.
The scientists recalibrated the baseline of pre-industrial temperatures using large-scale tree ring data sets and found it was cooler than previously thought. With this revised baseline, the Northern Hemisphere surpassed the Paris limits during the summer of 2023.
Study co-author Jan Esper expressed concern over the results, stating that it’s a “very concerning” situation and that he worries for future generations. However, reactions form other climate scientists were varied.
James Hansen, director of the Climate Science, Awareness and Solutions Program at Columbia University’s Earth Institute, agreed with the study’s findings and believes that the world has already surpassed the +1.5C global warming level relative to pre-industrial times.
Gavin Schmidt, director of the NASA Goddard Institute for Space Studies, called the study a good attempt at putting 2023 in a longer context but cautioned against using the results for global comparisons.
Michael Mann, University of Pennsylvania Presidential Distinguished Professor, was more critical of the research, stating that it doesn’t add much to the already-established evidence of unprecedented warming in at least the past 20,000 years. Though he didn’t deny the claims stated within the research.
The study reinforces the need for urgent action to mitigate climate change and its consequences. The authors of the study propose that governments and organizations must work together to implement policies and technologies that reduce greenhouse gas emissions in an effort to slow and ultimately reverse the effects of climate change.
This finding highlights the importance of continued research into historical climate data, which can help us better understand the scale and impact of current warming trends. It also highlights the urgency for collective action to address the pressing issue of climate change and its consequences.
