Global warming has directly profoundly disrupted the global snow cycle, driving widespread reductions in snow cover, earlier snowmelt, and increased seasonal instability. These changes threaten water resources, food security, and ecosystem sustainability across snow‑dependent regions, particularly in mid‑ to high‑latitude catchments where meltwater sustains agriculture, hydropower, and municipal supplies during summer months. In response, climate engineering—specifically stratospheric aerosol injection (SAI), which mimics volcanic cooling—has been proposed as a temporary complementary measure to curb surface warming while decarbonization efforts proceed.



This study evaluates the G6sulfur climate engineering scenario using outputs from six state‑of‑the‑art global climate models (CESM2‑WACCM, CNRM‑ESM2‑1, IPSL‑CM6A‑LR, MPI‑ESM1‑2‑HR, MPI‑ESM1‑2‑LR, and UKESM1‑0‑LL). All simulations are driven by the extreme SSP5‑8.5 emission pathway, with future projections (2070–2099) compared against a historical baseline (2015–2034). Four critical snow variables are analyzed: surface snow mass, snowmelt flux, snow cover fraction, and snow depth.



Under the unabated SSP5‑8.5 scenario, the models project severe declines across all indicators. Multi‑model averages show surface snow mass decreasing by approximately 25 %, snowmelt flux by 14 %, snow cover fraction by 27 %, and snow depth by as much as 50 % relative to baseline. Moreover, the timing of peak snow accumulation and melt shifts 1–2 months earlier, fundamentally altering runoff delivery to downstream regions during dry seasons when water demand is highest.



In stark contrast, the G6sulfur intervention substantially moderates these adverse trends. With stratospheric aerosol cooling active, snow mass loss is limited to ~11 %, snowmelt flux reduction to ~10 %, snow cover decline to ~12 %, and snow depth loss to ~19 %. The earlier occurrence of peak snow and melt is also delayed to less than half a month relative to baseline, restoring a more natural seasonal rhythm.



These findings demonstrate that SAI can effectively offset a substantial portion of global warming's negative impacts on the snow cycle. However, the intervention cannot fully reverse all hydrological changes residual warming persists, and snow dynamics remain sufficiently altered to affect streamflow timing and volume. Therefore, while SAI offers a valuable complementary tool for temporarily stabilizing snow‑related water resources, it is by no means a substitute for deep and rapid reductions in greenhouse gas emissions. Emission cuts must remain the cornerstone of any sustainable climate strategy, with climate engineering serving only as a short‑term palliative while long‑term decarbonization is achieved. The study reinforces that systemic societal transformation toward a low‑carbon future remains essential, ultimately, regardless of technological interventions.