A new study published in Nature Climate Change reveals that rapid, large-scale fluctuations in temperature from one day to the next have intensified under global warming, representing a distinct climate hazard with significant impacts on human health. This increasing volatility creates a weather pattern akin to a climate roller coaster, with populations experiencing more frequent and sharp swings between temperature extremes.

Conducted by scientists from Nanjing University and the Institute of Atmospheric Physics (IAP) at the Chinese Academy of Sciences (CAS), the research defines these events as occurring when the temperature difference between two consecutive days exceeds the 90th percentile of historical records. The analysis finds that such extreme day-to-day temperature changes have become more frequent and intense in low- to mid-latitude regions, with human-driven greenhouse gas emissions confirmed as the primary cause, based on optimal fingerprinting method.

Global Warming Intensifies Temperature “Roller Coasters”. (Image by Liu Qi)

Projections from climate models indicate this trend will continue. Under a high-emission scenario, the frequency and total intensity of these events could increase by approximately 17% and 20% by 2100, affecting regions where over 80% of the global population resides.

The study further explains the physical mechanism based on the composite change index method. "Global warming exacerbates soil drought and intensifies variability in sea-level pressure and soil moisture," said Xu Zhongfeng from IAP/CAS, an author of this study. "These processes reduce the surface's heat capacity and amplify fluctuations in cloud cover and radiation, ultimately leading to more rapid temperature swings."

Critically, the health impact of these sudden roller-coaster swings exceeds that of other temperature variables. Based on mortality data from Jiangsu Province, China, and the United States, the research finds the association with all-cause mortality follows a near-exponential pattern, particularly raising risks for cardiovascular and respiratory diseases.

The authors stress that this phenomenon is distinct from traditional extreme temperature indices. "This study establishes extreme day-to-day temperature change as a distinct and independent category of extreme climate event," said Fu Congbin, a CAS academician from Nanjing University and the corresponding author of this study. "Global warming is systematically intensifying these swings in the world's most populous regions, challenging public health and ecosystem stability. We recommend that relevant international scientific organizations formally recognize it as a new type of extreme weather event."