Surface Deposition in a Sulfate Geoengineering Scenario: Risks and Vulnerabilities for Soils and Human Health

The injection of SO₂ into the stratosphere has been proposed as a temporary countermeasure against global warming. The sulfate aerosols produced this way have the potential to reduce some of the surface warming that is a consequence of the increase in anthropogenic greenhouse gases, by reflecting part of the incoming solar radiation back to space. We consider here an extreme sulfate geoengineering scenario that attempts to maintain temperatures at 2020 levels while greenhouse gas emissions continue to grow steadily: we show how the amount of sulfate needed would be globally balanced out by the predicted decrease in tropospheric anthropogenic SO₂ emissions throughout the entire century, but the spatial distribution of the deposition would change. We show how these changes would affect soils differently depending on their different buffering capacity, and how highy populated areas might still see less deposition compared to the present day.