Liu et al. (2025) Global warming intensifies extreme day-to-day temperature changes in mid–low latitudes

Identification

• Journal: Nature Climate Change
• Year: 2025
• Date: 2025-11-21
• Authors: Qi Liu, Congbin Fu, Zhongfeng Xu, Aijun Ding
• DOI: 10.1038/s41558-025-02486-9

Research Groups

• School of Atmospheric Sciences, Nanjing University, Nanjing, People’s Republic of China
• Jiangsu Collaborative Innovation Center for Climate Change, Nanjing University, Nanjing, People’s Republic of China
• Institute for Climate and Global Change Research, Nanjing University, Nanjing, People’s Republic of China
• State Key Laboratory of Earth System Numerical Modelling and Application, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, People’s Republic of China

Short Summary

Global warming is intensifying extreme day-to-day temperature changes (DTDTs) in mid-low latitudes, a distinct and largely ignored extreme weather event, posing substantial risks to human health and ecosystems, with climate models projecting further amplification by 2100.

Objective

• To comprehensively understand the observed changes in extreme day-to-day temperature changes (DTDT) over past decades, including facts, anthropogenic contributions, future projections, and potential mechanisms.

Study Configuration

• Spatial Scale: Global land areas, with specific focus on low and mid-latitudes (e.g., 40° S–40° N, 45° S–45° N), high latitudes, western USA, eastern China, South America, and the Mediterranean region.
• Temporal Scale: Historical period: 1961–2020 (observations), 1961–2022 (reanalysis), 1961–2014 (CMIP6 historical simulations). Future projections: 2015–2100, 2050–2099. Return period analysis: 1950–1985, 1986–2021.

Methodology and Data

• Models used:
  • Coupled Model Intercomparison Project Phase 6 (CMIP6) Earth System Models (11 ESMs for simulations and projections).
  • CanESM5 and MPI-ESM1-2-LR for mechanism validation.
  • Statistical models: Optimal fingerprinting method (generalized multivariate linear regression), multiple linear regression for composite change index, generalized extreme value distribution for return periods, distributed lag nonlinear model combined with generalized additive mixed models for mortality associations.
• Data sources:
  • Observations: Berkeley Earth gridded daily maximum and minimum temperatures (1° × 1° resolution).
  • Reanalysis: NCEP/NCAR reanalysis (approx. 1.875° × 1.875° resolution), ERA5 reanalysis (2° × 2° resolution).
  • Mortality data: Non-accidental, cardiovascular, and respiratory disease mortality for 29 US cities and 41 cities in Jiangsu Province, China.

Main Results

• Extreme day-to-day temperature changes (DTDTs), defined as absolute daily maximum temperature differences exceeding the 90th percentile, are largely independent of 15 standard ETCCDI temperature indices.
• Since the 1960s, extreme DTDT events have become more frequent in low and mid-latitudes but decreased at high latitudes.
• Observed increases in amplitude, frequency, and total intensity of extreme DTDTs in low and mid-latitudes are 0.03–0.04 °C per decade, 0.4–0.5 events per decade, and 4–5 °C per decade, respectively.
• The increases are particularly pronounced over the western USA (11.1 °C per decade), eastern China (9.4 °C per decade), South America (12.4 °C per decade), and the Mediterranean region (7.1 °C per decade) for total intensity.
• Optimal fingerprinting analysis attributes these observed changes primarily to anthropogenic greenhouse gas (GHG) forcing.
• The intensification in low and mid-latitudes is linked to drier soil and increased variability in sea-level pressure and soil moisture.
• Climate models (CMIP6) project a further amplification of extreme DTDTs by 2100 under warming, with frequency, amplitude, and total intensity rising by approximately 17%, 3%, and 20%, respectively, in regions covering 80% of the global population under the SSP 5-8.5 scenario.
• Record-breaking spring extreme DTDT events in eastern China and the western USA, which occurred once every 1,000–3,000 years between 1950 and 1985, increased to once every 40–60 years between 1986 and 2021.
• Extreme DTDTs are strongly associated with increased mortality, with effects stronger than those of minimum temperature or diurnal temperature range (DTR).

Contributions

• Identifies extreme day-to-day temperature change (DTDT) as a distinct and critical aspect of extreme weather events, largely independent of existing ETCCDI indices, filling a significant knowledge gap.
• Provides a comprehensive global analysis of observed historical trends, anthropogenic attribution, future projections, and underlying physical mechanisms of extreme DTDTs.
• Quantifies the rapid increase in frequency and intensity of extreme DTDTs, particularly in densely populated mid-low latitudes, and links these changes to specific climatic drivers (drier soil, increased pressure/soil moisture variability).
• Demonstrates the significant and distinct impacts of extreme DTDTs on human mortality, highlighting their greater impact compared to other temperature variability metrics.
• Highlights the urgent need for improved prediction, adaptation, and mitigation strategies for these rapidly intensifying extreme events.

Funding

• National Key Research and Development Program of China (2023YFF0805503, 2022YFF0802503)
• Natural Science Foundation of Jiangsu Province, China (BK20241220)
• Chinese Jiangsu Collaborative Innovation Center for Climate Change
• Frontiers Science Center for Critical Earth Material Cycling of Nanjing University

Citation

@article{Liu2025Global,
  author = {Liu, Qi and Fu, Congbin and Xu, Zhongfeng and Ding, Aijun},
  title = {Global warming intensifies extreme day-to-day temperature changes in mid–low latitudes},
  journal = {Nature Climate Change},
  year = {2025},
  doi = {10.1038/s41558-025-02486-9},
  url = {https://doi.org/10.1038/s41558-025-02486-9}
}

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