Argument: Injecting sulfur into the atmosphere means more acid rain
Alan Robock. "Has the time come for geoengineering?" The Bulletin. August 14th, 2008: "5. More acid deposition. If sulfate is injected regularly into the stratosphere, no matter where on Earth, acid deposition will increase as the material passes through the troposphere—the atmospheric layer closest to Earth’s surface. In 1977, Russian climatologist Mikhail Budyko calculated that the additional acidity caused by sulfate injections would be negligibly greater than levels that resulted from air pollution.10 But the relevant quantity is the total amount of acid that reaches the ground, including both wet (acid rain, snow, and fog) and dry deposition (acidic gases and particles). Any additional acid deposition would harm the ecosystem, and it will be important to understand the consequences of exceeding different biological thresholds. Furthermore, more acidic particles in the troposphere would affect public health. The effect may not be large compared to the."