Yang et al. (2025) Lakes are experiencing more severe heatwaves than the atmosphere

Identification

• Journal: Communications Earth & Environment
• Year: 2025
• Date: 2025-11-24
• Authors: Yifang Yang, Jianming Deng, R. Iestyn Woolway, Erik Jeppesen, Kun� Shi, Boqiang Qin, Yingcheng Lu, Yunlin Zhang, Zheng Tang
• DOI: 10.1038/s43247-025-02907-9

Research Groups

• Key Laboratory of Lake and Watershed Science for Water Security, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
• International Institute for Earth System Science, Nanjing University, Nanjing, China
• School of Atmospheric Sciences, Nanjing University, Nanjing, China
• School of Ocean Sciences, Bangor University, Menai Bridge, United Kingdom
• Department of Ecoscience and WATEC, Aarhus University, Aarhus, Denmark
• Sino-Danish Centre for Education and Research (SDC), University of Chinese Academy of Sciences, Beijing, China
• Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Sciences, Yunnan University, Kunming, China
• Institute of AI for Industries, Chinese Academy of Sciences, Nanjing, China

Short Summary

This study globally compares lake and atmospheric heatwaves from 2000-2022, revealing that lake heatwaves are more severe, with longer durations and shorter reoccurrence periods, primarily driven by reduced wind speed.

Objective

• To clarify the differences in trends, spatial distributions, and characteristics between atmospheric heatwaves (AHWs) and lake heatwaves (LHWs) globally.
• To test if LHWs are more severe than AHWs due to water's high specific heat capacity.
• To investigate if decreasing wind speed exacerbates LHWs by enhancing stratification and limiting heat dissipation.
• To characterize atmosphere-lake coupled heatwave events (CHWs) to improve forecasting and adaptation strategies for freshwater ecosystems.

Study Configuration

• Spatial Scale: 265 lakes worldwide, with surface areas exceeding 100 square kilometers, spanning latitudes between 54.6°S and 71.0°N.
• Temporal Scale: 2000–2022 for historical analysis; projections up to 2100 for future climate change scenarios.

Methodology and Data

• Models used:
  • Machine learning models (LightGBM, Random Forest, Extra Trees, genetic algorithm-optimised back-propagation neural network) for estimating missing daily water temperature data.
  • CMIP6 Earth-system models (GFDL-ESM4, IPSL-CM6A-LR, MPI-ESM1-2-HR, MRI-ESM2-0, UKESM1-0-LL) for future projections under SSP126, SSP370, and SSP585 scenarios.
  • Random-Forest analysis for attributing environmental drivers.
  • Structural Equation Modelling (via partial least squares path modelling) for spatial distribution patterns.
• Data sources:
  • Daily surface water temperature: MODIS MOD11A1 v6 product (Terra satellite).
  • Daily air temperature, sensible-heat flux, latent-heat flux, long-wave and short-wave radiation, wind speed, atmospheric pressure: ERA5-Land reanalysis (0.1° resolution).
  • In-situ air temperature observations: World Meteorological Organization stations (for ERA5-Land validation).
  • Lake morphology (depth, surface area, geographical coordinates): GLAKES dataset.
  • Annual mean chlorophyll-a concentrations: MODIS Aqua L3SMI product.
  • Annual mean Normalized Difference Vegetation Index (NDVI): MOD13A1 v6 product.
  • Lake transparency data: 2019 global lake transparency distribution dataset.
  • Future climate fields: ISIMIP3 bias-adjusted archive (0.5° × 0.5° resolution, downscaled to 0.1°).

Main Results

• Lake heatwaves (LHWs) were more severe than atmospheric heatwaves (AHWs) globally from 2000–2022, exhibiting longer accumulated heatwave days (29.7 ± 0.2 days vs. 18.0 ± 0.3 days), shorter reoccurrence periods (86.9 ± 1.6 days vs. 121.4 ± 2.3 days), and greater cumulative heat (CHI: 14.9 ± 0.1 days·°C vs. 12.7 ± 0.2 days·°C).
• The frequency and total heatwave days for LHWs increased faster than for AHWs during the study period (e.g., LHW frequency rose by +1 event per decade for 71% of lakes).
• Atmosphere-lake coupled heatwaves (CHWs) showed greater intensity and longer durations than isolated events, with their annual occurrence probability increasing significantly over time.
• From a long-term perspective, reduced wind speed was identified as the key driver of the differences between LHWs and AHWs, with a mean wind speed reduction of -0.18 meters per second during LHWs in 205 lakes.
• Spatially, lake location (latitude) was the primary determinant of heatwave disparities, followed by lake area and depth, with deeper lakes showing greater buffering capacity.
• Under a fixed-baseline high-emission scenario (SSP585), both LHWs and AHWs are projected to intensify by 2100, but AHWs are expected to accelerate more rapidly, causing the differences between LHWs and AHWs to diminish, with cumulative severity of AHWs potentially exceeding LHWs by the early 2030s.

Contributions

• This is the first study to globally compare the differences between heatwaves in lakes and the overlying atmosphere.
• It quantifies the severity, trends, and drivers of LHWs, AHWs, and coupled heatwave events (CHWs) using a comprehensive global dataset of 265 lakes.
• It identifies reduced wind speed as a key long-term driver of the disparities between lake and atmospheric heatwaves.
• It highlights the dominant role of lake location (latitude) and morphology (depth, area) in spatially determining heatwave differences.
• The findings provide a foundation for improved forecasting and the development of effective adaptation strategies for freshwater ecosystems, emphasizing the importance of wind conditions in future lake heatwave management.

Funding

• National Natural Science Foundation of China (Grant Nos. 42371016 and 42220104010)
• 14th Five-Year National Key Research and Development Program of China (2022YFC3202004)
• Fundamental Research Funds for the Central Universities (0904-14380035)
• UKRI Natural Environment Research Council (NERC) Independent Research Fellowship [NE/T011246/1]
• Yunnan Provincial Council of Academicians and Experts Workstations (202405AF140006)

Citation

@article{Yang2025Lakes,
  author = {Yang, Yifang and Deng, Jianming and Woolway, R. Iestyn and Jeppesen, Erik and Shi, Kun� and Qin, Boqiang and Lu, Yingcheng and Zhang, Yunlin and Tang, Zheng},
  title = {Lakes are experiencing more severe heatwaves than the atmosphere},
  journal = {Communications Earth & Environment},
  year = {2025},
  doi = {10.1038/s43247-025-02907-9},
  url = {https://doi.org/10.1038/s43247-025-02907-9}
}