Miah et al. (2025) Irreversibility of extreme precipitation intensity in global monsoon areas under multiple carbon neutrality scenarios

Identification

• Journal: Weather and Climate Extremes
• Year: 2025
• Date: 2025-12-06
• Authors: Md. Babul Miah, Jong‐Yeon Park, Min-Uk Lee, Woojin Jeon, Young‐Hwa Byun, Hyun Min Sung, Jin Gi Hong, Md. Jalal Uddin, Sanjit Kumar Mondal
• DOI: 10.1016/j.wace.2025.100843

Research Groups

• Department of Environment and Energy, Jeonbuk National University, Jeonju, South Korea
• Department of Earth and Environmental Sciences & Earth Environmental System Research Center, Jeonbuk National University, Jeonju, South Korea
• National Institute of Meteorological Science, Jeju, South Korea
• Department of Civil Engineering and Construction Engineering Management, California State University, Long Beach, CA, USA
• Institute of Disaster Management, Khulna University Engineering & Technology, Khulna, Bangladesh
• Irreversible Climate Change Research Center, Yonsei University, Seoul, South Korea

Short Summary

This study investigates the irreversibility of extreme precipitation intensity across seven Global Monsoon Area (GMA) sub-regions under eight distinct carbon neutrality scenarios. It reveals that extreme precipitation intensity exhibits irreversible behavior, failing to return to initial levels even after atmospheric carbon dioxide (CO2) reduction, with regional vulnerabilities significantly influenced by the timing and rate of carbon neutrality.

Objective

• To assess how sensitive the irreversibility of extreme precipitation is to the timing of achieving carbon neutrality.
• To determine to what extent faster CO2 removal can mitigate the degree of irreversibility across global monsoon regions.
• To explore the physical mechanisms underlying these irreversible changes in extreme precipitation.

Study Configuration

• Spatial Scale: Global Monsoon Areas (GMAs), specifically seven sub-regions: East Asia (110°E−145°E, 30°N–55°N), North Africa (10°W–40°E, 5°N–22°N), South Asia (62°E−110°E, 5°N–28°N), Central America (70°W–120°W, 4°N–28°N), South Africa (10°E−40°E, 4°S–25°S), Australia (120°E−150°E, 8°S–26°S), and South America (100°W–145°W, 6°S–30°S).
• Temporal Scale: Future scenarios with CO2 concentrations increasing at 1% per year from pre-industrial levels until reaching peak thresholds (440, 470, 570, and 1145 ppm), followed by a decrease at either 1% or 2% per year. Analysis periods are 30-year windows: PUp (CO2 increase phase), PPeak (CO2 peak phase), and PDown (CO2 decrease phase, returning to PUp levels).

Methodology and Data

• Models used: UKESM1 (NIMS_UKESM) climate model, with three ensemble runs. For robustness, comparison with multi-model ensemble mean from eight CMIP6-CDRMIP Earth system models (ACCESS-ESM1-5, CNRM-ESM2-1, CanESM5, MIROC-ES2L, NorESM2-LM, CESM2, GFDL-ESM4, and UKESM1-0-LL).
• Data sources: Model simulations (NIMS_UKESM1 and CMIP6-CDRMIP). Reanalysis data used for comparison of Rx1day spatial patterns.

Main Results

• Extreme precipitation intensity (Rx1day) exhibits irreversible behavior in GMAs, failing to return to initial levels even after atmospheric CO2 concentrations decline.
• The degree of irreversibility is significantly amplified by delays in achieving carbon neutrality and by slower CO2 emission reduction rates.
• The irreversible response is nonlinear to the magnitude of carbon forcing, leading to distinct regional vulnerabilities; some regions show sharp increases in irreversibility with small delays, while others exhibit exponential-like increases at higher CO2 levels.
• Faster CO2 removal rates (2% per year) consistently result in lower levels of irreversibility across all regions compared to slower rates (1% per year).
• Irreversibility is driven by increased variability in daily precipitation (linked to persistent warming and thermodynamic effects) and/or overall increases in mean precipitation (modulated by global sea surface temperature (SST) patterns).
• Moisture budget analysis reveals regional differences: East Asia shows dominant thermodynamic contributions (increased atmospheric moisture), while most tropical monsoon regions show stronger dynamic contributions (changes in atmospheric circulation, Intertropical Convergence Zone shifts).
• The findings are largely robust and consistent with the CMIP6 multi-model ensemble mean, supporting the physical consistency of the irreversible response.

Contributions

• Provides a novel assessment of extreme precipitation irreversibility across GMAs under a comprehensive set of eight carbon neutrality scenarios, extending beyond conventional single ramp-up/ramp-down experiments.
• Quantifies region-specific vulnerabilities to the timing and rate of carbon neutrality, identifying areas most susceptible to irreversible hydroclimatic shifts.
• Elucidates the physical mechanisms driving irreversibility, distinguishing between thermodynamic (moisture flux) and dynamic (wind) drivers and their links to persistent SST anomalies (e.g., El Niño-like warming, interhemispheric differential warming).
• Offers a scientific basis for developing regionally tailored adaptation strategies and underscores the urgency of rapid policy implementation to mitigate growing extreme precipitation risks.

Funding

• Korea Meteorological Administration Research and Development Program (Grant No. RS-2025-02309058)
• National Research Foundation of Korea (NRF) (Grant No. RS-2023-00207866)

Citation

@article{Miah2025Irreversibility,
  author = {Miah, Md. Babul and Park, Jong‐Yeon and Lee, Min-Uk and Jeon, Woojin and Byun, Young‐Hwa and Sung, Hyun Min and Hong, Jin Gi and Uddin, Md. Jalal and Mondal, Sanjit Kumar},
  title = {Irreversibility of extreme precipitation intensity in global monsoon areas under multiple carbon neutrality scenarios},
  journal = {Weather and Climate Extremes},
  year = {2025},
  doi = {10.1016/j.wace.2025.100843},
  url = {https://doi.org/10.1016/j.wace.2025.100843}
}