2024 break temperature records
In a study published in Nature on Tuesday, researchers revealed that the summer of 2023 ranked as the hottest in the Northern Hemisphere in the past two millennia. This scorching heat was not only a result of natural climate variations but was significantly exacerbated by manmade climate change, compounded by an El Niño weather cycle.
Previously, scientists had identified 2023 as the hottest year since modern temperature records began in 1850. By combining instrumental measurements with climate reconstructions, researchers were able to establish a 2,000-year record. They found that the extreme warmth experienced last summer not only shattered modern records but also surpassed the warmest summer prior to the instrumental record, dating back to the year 246, by more than half a degree Celsius, accounting for almost all natural climate variations. Moreover, it was nearly 4 degrees Celsius warmer than the coldest summer on record, which occurred in 536.
Ulf Büntgen, a study co-author from the University of Cambridge in the UK, emphasized the profound impact of recent global warming on our planet’s history. “When you look at the long sweep of history, you can see just how dramatic recent global warming is,” Büntgen stated. He warned that unless there is a significant reduction in greenhouse gas emissions, the trend of exceptionally hot years, like 2023, will persist.
To conduct their analysis, Büntgen and his colleagues focused on landmasses between the 30th parallel north and the North Pole, as this region hosts most of the world’s longstanding meteorological stations. They reconstructed historical climate conditions by examining thousands of tree rings from nine regions in the Northern Hemisphere. Since tree growth is influenced by weather conditions, tree rings serve as valuable indicators of past temperatures. Given the strong correlation between tree rings and summer temperatures, the researchers concentrated on the months of June through August.
They found a lack of consistency between tree-ring-enabled climate reconstructions and instrument-based measurements during the second half of the 19th century, raising the question of whether older thermometers produced inaccurately high temperature readings. The consequence of that, according to the researchers, is a “systematic warm bias” in early instrumental observations, which are used widely as the baseline for global climate science.
The tree-ring data also unveils that the majority of cooler periods over the past 2,000 years occurred following major volcanic eruptions.
These eruptions released “It’s true that the climate is constantly evolving, but the warming observed in 2023, primarily driven by greenhouse gas emissions, is further exacerbated by El Niño conditions,” stated Jan Esper, the lead author of the study and a professor of climate geography at Johannes Gutenberg University Mainz in Germany. He emphasized that this combination leads to longer and more severe heatwaves and prolonged periods of drought.
The study highlights that the goal set in the 2015 Paris Agreement to limit temperature increases to 1.5 degrees Celsius above pre-industrial levels “has already been surpassed” in the Northern Hemisphere. While this conclusion may not be universally applicable on a global scale due to variations in warming rates among different regions and surfaces, the research findings clearly illustrate the unprecedented nature of present-day warmth on large scales, as noted by the authors.
The study further corroborates the warnings issued by certain climate scientists: with climate change intensified by El Niño conditions, 2024 is anticipated to witness the breaking of temperature records once more. In recent weeks, numerous countries across Asia have endured exceptional heatwaves. For instance, Myanmar recently recorded its highest-ever April temperature, reaching 48.2 degrees Celsius.