Tian et al. (2026) Weakening mountain vegetation aspect asymmetry due to altered energy conditions

Identification

• Journal: Nature Climate Change
• Year: 2026
• Date: 2026-01-12
• Authors: Qing Tian, Feng Gao
• DOI: 10.1038/s41558-025-02542-4

Research Groups

• Hubei Key Laboratory of Quantitative Remote Sensing of Land and Atmosphere, School of Remote Sensing and Information Engineering, Wuhan University, Wuhan, China
• Perception and Effectiveness Assessment for Carbon-neutrality Efforts, Engineering Research Center of Ministry of Education, Wuhan, China

Short Summary

This study quantifies a weakening trend of mountain vegetation aspect asymmetry across the Northern Hemisphere from 2003 to 2024, attributing these changes primarily to altered solar radiation and temperature conditions.

Objective

• To quantify the difference in vegetation density between polar-facing and equatorial-facing slopes (aspect asymmetry) across the Northern Hemisphere and understand how local topography modulates the impacts of climate change on mountain vegetation growth at large scales.

Study Configuration

• Spatial Scale: Mountain areas across the Northern Hemisphere.
• Temporal Scale: 2003 to 2024.

Methodology and Data

• Models used: Google Earth Engine (GEE) for computation of aspect asymmetry, R (ggplot2) for visualization.
• Data sources:
  • Mountainous areas dataset (ScienceBase).
  • Spatial aridity index dataset (Consortium for Spatial Information).
  • AW3D30 (ALOS global digital surface model).
  • MODIS-based LAI (Leaf Area Index) dataset.
  • ESA WorldCover (10 m 2021 v200).
  • TerraClimate (high-resolution global dataset of monthly climate and climatic water balance from 1958–2015).

Main Results

• A significant weakening trend of vegetation aspect asymmetry was observed across the Northern Hemisphere from 2003 to 2024.
• In regions where polar-facing slopes initially showed higher vegetation density, the magnitude, area, and seasonal duration of aspect asymmetry all decreased.
• This decrease implies a reduction in water control on vegetation growth in these specific regions.
• The observed changes in vegetation aspect asymmetry are primarily attributable to hydrothermal conditions, with solar radiation and temperature identified as the dominant climatic factors.

Contributions

• Provides a large-scale quantification of mountain vegetation aspect asymmetry and its temporal changes across the Northern Hemisphere.
• Identifies a weakening trend in aspect asymmetry, highlighting an underexplored but important aspect of mountain ecosystem response to climate change.
• Attributes these changes to specific hydrothermal conditions, particularly solar radiation and temperature, offering insights into the underlying mechanisms.
• Suggests implications for ecological stability in mountain regions under ongoing climate change.

Funding

• National Key Research and Development Program of China (2023YFF1303702)

Citation

@article{Tian2026Weakening,
  author = {Tian, Qing and Gao, Feng},
  title = {Weakening mountain vegetation aspect asymmetry due to altered energy conditions},
  journal = {Nature Climate Change},
  year = {2026},
  doi = {10.1038/s41558-025-02542-4},
  url = {https://doi.org/10.1038/s41558-025-02542-4}
}