Regional and seasonal hydrological changes with and without stratospheric aerosol intervention under high greenhouse gas climates

However, in wetter or cooler climates, such as the Amazon, middle and southern Africa and east Europe, they only partly reverse the reductions in available water (AW) and runoff caused by high GHG emissions. Residual warming and snowmelt dynamics play an important role in runoff at mid‐to‐high latitudes. Additionally, SAI does not completely suppress GHG‐induced vegetation expansion and so over‐reduces global runoff in three latitude bands: 45°–65°N, 45°–65°S, and 30°S to 0 with end‐of‐century decreases of 4.1% under G6Sulfur and 7.3% under Geo‐SAI despite mean AW levels remaining close to present‐day.

These findings emphasize that although SAI mitigates many climate‐driven hydrological disruptions, its unintended effects on runoff, vegetation feedback, and regional water availability warrants study—especially in regions heavily dependent on surface water resources.