SRM isn't difficult to reverse. Sulfur dioxide in the stratosphere would fall out in a year or two; we've directly observed that with emissions from volcanoes,

SRM isn't difficult to reverse. Sulfur dioxide in the stratosphere would fall out in a year or two; we've directly observed that with emissions from volcanoes, which are of similar scale. Another idea, to seed low-lying clouds with seawater, would reverse in about a week after we stopped doing it.