"2024 Record Heatwave Not an Unexpected Anomaly, Says US Research Team"

US Research Team Rebuts Claims of "Anomalous Heat Events"
Says "Existing Climate Models Are Sufficient to Explain" Recent High Temperatures
Without Human Activity, 2024 Would Be a Once-in-a-Millennium Event

A study has found that the record-high global average temperature in 2024 can be fully explained by existing climate models.

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According to Yonhap News Agency on May 12, a research team led by Professor Michael Mann at the University of Pennsylvania published a paper in the Proceedings of the National Academy of Sciences (PNAS), stating, “By combining surface temperature observation data from the past 30 years with climate model simulations to analyze the likelihood of the record-high temperatures in 2024, we found that such an event could occur roughly once every eight years under current climate conditions that account for global warming.”

The research team took note of recent studies claiming that the record-breaking temperatures of 2023–2024 represent an “anomalous phenomenon unexplained by existing climate models” and that “global warming may be progressing faster than previously anticipated.”

For instance, a research group led by former NASA climate scientist James Hansen stated in a paper published in February that “the sharp temperature rise in 2023–2024 cannot be explained by El Niño alone.” In addition, Robert Rohde, chief scientist at the climate research organization Berkeley Earth, remarked that “the rapid succession of new records in 2023–2024 is evidence that recent global warming is progressing faster than expected.”

To verify these claims, the present study employed a semi-empirical methodology that combined surface temperature observation data with multi-model simulations from the sixth phase of the Coupled Model Intercomparison Project (CMIP6). The study also utilized Monte Carlo simulations to account for temperature changes due to long-term human activities and natural factors, as well as internal climate variability.

Photo to help understand the article. Pixabay

The analysis revealed that the global mean surface temperature (GMST) in 2024, further influenced by a strong El Niño in 2023–2024, was approximately 0.25°C higher than the previous record set in 2016, with the probability of such an occurrence calculated at about 12%. The high temperature event in 2016 was found to have a similar probability of about 14%. In contrast, the hot weather event in 1998, which was also driven by a strong El Niño, had a probability of 2.5%—meaning it could be expected to occur only once every 40 years—making it the only statistically exceptional high-temperature event among the past 30 years.

The research team concluded, “Recent high-temperature events, including the record in 2024, can be sufficiently explained by standard climate model simulations that account for the effects of global warming. No evidence was found for an unexpectedly accelerated pace of global warming.” However, they added, “If the human-induced effects of warming are excluded, the 2024 record would qualify as an extremely rare event, expected only once every 1,000 years. Virtually all recent record-high temperatures would have been extremely unlikely without global warming.”

The team further noted, “This study demonstrates that recent record-high temperatures do not contradict the historical reconstructions or future projections of established climate models. The current state-of-the-art climate models still provide a reliable foundation for assessing global warming and formulating climate policy.”

This content was produced with the assistance of AI translation services.