Liu et al. (2026) Historical diurnal temperature range trends constrain future climate projections

Identification

• Journal: Communications Earth & Environment
• Year: 2026
• Date: 2026-01-13
• Authors: Anqi Liu, Daokai Xue, Ben Yang, X. Huang
• DOI: 10.1038/s43247-026-03185-9

Research Groups

• School of Atmospheric Sciences, Nanjing University, Nanjing, China

Short Summary

This study identifies a robust emergent relationship between historical diurnal temperature range (DTR) trends and future DTR projections across global and regional scales. Leveraging this relationship, the authors develop a framework to constrain regional climate projections, significantly reducing model uncertainties in future DTR changes.

Objective

• To identify and leverage an emergent relationship between historical diurnal temperature range (DTR) trends and future DTR projections to reduce uncertainties in regional climate projections under global warming.

Study Configuration

• Spatial Scale: Global land areas (excluding Antarctica), focusing on 27 out of 44 IPCC AR6 reference regions, with specific attention to the Northern Hemisphere, Eurasian continent, mid-latitudes, and high latitudes.
• Temporal Scale:
  • Historical observations: 1901–2022 (CRU TS), with trend analysis for 1981–2014 and extended to 1981–2024.
  • Future projections: 2070–2099 relative to 1851–1900, and 2015–2100 for CMIP6 simulations.

Methodology and Data

• Models used: 26 models from the Coupled Model Intercomparison Project Phase 6 (CMIP6) for historical, SSP2-4.5, and SSP5-8.5 experiments.
• Data sources:
  • Climatic Research Unit Time-Series version 4.07 (CRU TS) dataset (daily maximum and minimum temperature, 0.5° × 0.5° monthly resolution).
  • CMIP6 model data (daily minimum and maximum temperatures, monthly radiation fluxes, precipitation, and cloud cover).
• Methods: Emergent constraint (EC) method, nonparametric Mann–Kendall test for trend analysis, linear regression to isolate external influences, and Student’s t-test for statistical significance.

Main Results

• A strong, statistically significant emergent relationship exists between historical DTR trends (1981–2014/2024) and future DTR changes (2070–2099 relative to 1851–1900), robust across various emissions scenarios and land areas.
• This emergent relationship is valid for 27 of the 44 IPCC AR6 reference regions, particularly across the Eurasian continent and the Northern Hemisphere.
• The proposed emergent constraint framework reduces inter-model uncertainties in future DTR projections by 15% to 68% across these 27 regions, with the highest reduction (68.39%) observed over the Tibetan Plateau.
• Constrained projections generally indicate a decline in DTR in a warming future, with values as low as -0.41 K/K in the Russian Arctic Region. However, increases in DTR are projected in regions such as the South American Monsoon, the Mediterranean, and Western Central Asia.
• The physical mechanism for the emergent relationship is primarily linked to the sustained influence of external forcing (e.g., greenhouse gases) on DTR, driven by widespread reductions in cloud cover. Reduced cloud cover increases daytime surface downwelling shortwave radiation (RSDS) and decreases nighttime surface downwelling longwave radiation (RLDS), leading to higher DTR.
• Surface sensible heat flux (HFSS) and surface latent heat flux (HFLS) also contribute to DTR changes, with their effects amplified by long-term precipitation deficits and low soil moisture.
• Seasonal analysis reveals that the reduction in DTR during winter and spring primarily drives the overall annual DTR change. The emergent relationship weakens at higher latitudes during winter due to limited solar radiation.

Contributions

• Identifies and quantifies a novel emergent constraint on future diurnal temperature range (DTR) changes, addressing a gap in climate projection uncertainty reduction.
• Provides a robust framework to refine regional DTR projections, significantly reducing inter-model uncertainties (15–68%) across IPCC AR6 reference regions.
• Offers valuable insights into the physical mechanisms driving DTR changes, highlighting the persistent role of external forcing (especially cloud cover and radiative fluxes) over internal variability.
• Delivers more precise regional climate projections, which are crucial for informed local climate adaptation planning and policy decisions.

Funding

• National Natural Science Foundation of China [Grant 425B2035]

Citation

@article{Liu2026Historical,
  author = {Liu, Anqi and Xue, Daokai and Yang, Ben and Huang, X.},
  title = {Historical diurnal temperature range trends constrain future climate projections},
  journal = {Communications Earth & Environment},
  year = {2026},
  doi = {10.1038/s43247-026-03185-9},
  url = {https://doi.org/10.1038/s43247-026-03185-9}
}