 The two main sulfuric acid precursors are sulfur dioxide (SO2) from anthropogenic sources and volcanoes, and dimethyl sulfide (DMS) from biogenic sources, especially marine plankton.These aerosols can cause a cooling effect on earth.However the UNFCCC has noted that sulfate aerosols remain in the atmosphere for only a short amount of time in comparison to well-mixed greenhouse gases, and therefore their cooling is localized and temporary.