[1] In the paper “Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols” (Journal of Geophysical Research, 114, D14109, doi:10.1029/2009JD011918, 2009), there are two errors that wewould like to correct. The first is an arithmetic error. In contrast to our calculation of the average global surface sulfur emissions of 5.41 × 10 kg Sm a, the correct value is 2.67 × 10 kg S m a. This value was calculated as a reference value, so this correction actually strengthens our conclusions that the additional amount of sulfur from geoengineering would be much smaller than current sources. [2] The second error involves our incorrect application of a formula. In section 4, we convert model output of sulfate deposition, given in kg SO4 m −2 a, to a form used in critical loading studies, mEq m a. Our formula as printed reads