| 02 Jul 2026
Multi-scenario Hydro-climatic Mean and Peak Responses of Central–South Asia and the Tibetan Plateau to Future Warming and Stratospheric Aerosol Intervention
Abstract. Central–South Asia and the Tibetan Plateau are climate-sensitive regions where water resources are controlled by monsoon, westerlies, and cryosphere processes. This study evaluates hydroclimatic changes across three regimes: moisture-limited Central Asia (west (WCA) and east (ECA)), cryosphere-influenced Tibetan Plateau (TIB), and monsoon-dominated South Asia (SAS), under warming (SSP2-4.5, SSP5-8.5) and solar radiation management (SRM) scenarios with temperature-stabilized (G6-1.5K-SAI and Geo-SAI) and transient forcing (G6solar and G6sulfur) experiments using CESM2-WACCM for 2055–2084 relative to 2015–2034. Warming substantially amplifies annual peak hydroclimatic responses, with peak temperature increasing by 24 %, ET by 6.5 %, precipitation by up to 13 % in TIB and SAS, and available water (AW) by 18 %–23 %, alongside accelerated cryosphere melts and enhanced vegetation. In contrast, dry Central Asia shows smaller precipitation and AW increases but remains highly sensitive to evapotranspiration (ET)-driven drying and soil moisture (SM) losses. Temperature-stabilized scenarios provide stronger and more consistent suppression of warming and extremes, while transient forcing scenarios achieve only partial mitigation and retain greater variability. Across regions, SRM generally reduces temperature and ET, produces mixed precipitation responses, and partially restores AW, soil moisture, and cryosphere-related processes. The findings per unit sulfur injected exhibit highest cooling and hydrological efficiency under G6-1.5K-SAI, showing that effectiveness depends on both sulfur loading and injection strategy. SRM also moderates cryosphere loss through enhanced snowfall and reduced snowmelt over the TIB. Warming intensifies seasonal variability and advances peak timing, whereas SRM dampens these shifts to present-day conditions. Precipitation remains the dominant control on AW, indicating that SRM primarily modifies hydroclimatic magnitude rather than underlying water-cycle controls. Overall, SRM reduces hydroclimatic extremes but cannot fully offset regional water stress, and its effectiveness depends on both forcing pathway and intervention strategy, highlighting the need for climate-regime-specific and sulfur-normalized evaluation.
Review Report (egusphere-2026-3008 (ESD))
Manuscript Title: “Multi-scenario Hydro-climatic Mean and Peak Responses of Central–South Asia and the Tibetan Plateau to Future Warming and Stratospheric Aerosol Intervention”.
General Assessment
Dear Editor, thank you for providing me a chance to review the above-mentioned manuscript draft. I have critically reviewed it and provide constructive comments to authors, which I believe significantly improves the manuscript’s quality and increases reader’s and scientific community interest. This manuscript presents a comprehensive analysis of hydroclimatic responses to multiple Stratospheric Aerosol Injection (SAI) and solar radiation modification (SRM) experiments using CESM2-WACCM simulations under the GeoMIP framework. The study focuses on regional hydroclimatic changes over Asia, including the Tibetan Plateau, Central Asia, and monsoon-dominated regions, and introduces sulfur-normalized efficiency metrics and “available water” (AW) diagnostics.
The topic is relevant to current SRM research and climate intervention assessment. The use of multiple GeoMIP-style experiments (G6solar, G6sulfur, Geo-SAI, and G6-1.5K-SAI) strengthen this draft. However, the manuscript in its current form suffers from methodological inconsistencies, insufficient justification of derived metrics, and overstated physical interpretations of statistical diagnostics. Furthermore, its novelty relative to existing GeoMIP literature is not clearly established.
I recommend major revision before the manuscript can be considered for publication.
Major Comments
The manuscript does not sufficiently distinguish its contribution from prior SRM and GeoMIP studies, particularly:
The analysis framework used here (CESM2-WACCM, G6 experiments, precipitation–evapotranspiration diagnostics, and regional hydroclimatic partitioning) is largely consistent with existing literature, with incremental rather than transformative novelty.
Required revision:
The authors must clearly articulate:
Without this, the manuscript risks being perceived as a regional re-analysis of established GeoMIP outputs rather than a novel contribution.
The manuscript defines AW as:
AW = Precipitation − Evapotranspiration
This is problematic because:
Yet the manuscript repeatedly interprets AW as:
Required revision:
The authors must:
Failure to do so leads to systematic over-interpretation of model output.
The manuscript introduces sulfur-normalized response metrics to evaluate SRM “efficiency.” However:
This raises concerns about physical interpretability and comparability across experiments.
Required revision:
The authors must:
A critical methodological issue arises from the use of inconsistent baselines:
Despite acknowledgment, the manuscript still:
This introduces structural bias.
Required revision:
The authors must either:
Several statements in the manuscript imply causality beyond what is supported by the experimental design, such as:
However, SRM impacts in CESM2-WACCM are:
Required revision:
The discussion must:
The manuscript does not adequately address:
Given SRM sensitivity to variability, this is a major omission.
Required revision:
Include:
The multiple linear regression (MLR) framework shows:
This suggests the model may be:
Required revision:
Minor Comments
Overall Recommendation
I strongly recommend authors to thoroughly revised the manuscript draft by keeping in mind the detailed comments raised above with major and minor revisions. I am recommending major revisions to authors.