Study identifies sharp swings in daily temperatures as new climate threat

A new study has revealed that abrupt and substantial day-to-day temperature fluctuations are intensifying in both frequency and severity as a result of climate change, representing a serious, distinct threat to public health.

Published in Nature Climate Change, the research was conducted by scientists from Nanjing University and the Institute of Atmospheric Physics (IAP) at the Chinese Academy of Sciences (CAS).

The study indicates that across low to mid-latitude regions, sharp temperature variations are becoming more frequent and extreme. Through a technique known as optimal fingerprinting, the researchers confirmed that greenhouse gas emissions caused by humans are the primary driver behind this trend.

Climate projections suggest the situation will continue to deteriorate. In a high-emissions scenario, the frequency of these sudden temperature swings could increase by approximately 17 percent by 2100, with their total intensity rising by 20 percent. This would affect areas that are collectively home to more than 80 percent of the global population.

The study also outlines the physical mechanism behind the trend. "Global warming exacerbates soil drought and amplifies variability in sea-level pressure and soil moisture," said Xu Zhongfeng, a professor at the IAP. "These changes reduce the land's thermal capacity and magnify fluctuations in cloud cover and solar radiation, ultimately leading to more pronounced temperature swings from one day to the next."

Of particular concern is the significant health impact associated with these abrupt changes. Based on mortality data from east China's Jiangsu Province and the United States, the study has identified a strong, near-exponential relationship between day-to-day temperature variability and all-cause mortality. The risks of cardiovascular and respiratory diseases are particularly heightened.

"This study establishes extreme day-to-day temperature variability as a unique, independent category of extreme climate event," said Fu Congbin, a CAS academician.

"Global warming is systematically amplifying these temperature swings across the world's most populated regions, posing a major challenge to public health and ecosystem stability. We urge relevant international scientific bodies to formally recognize it as a new type of extreme weather event," he said.