This corrigendum revokes an unfortunate short sentence which appears in two places in our above-mentioned article (on pp. 258 and 267, respectively) claiming that volcanic ash contains black graphite and carbon particles. Indeed, such sentence makes little sense in the context of our article. The unfortunate sentence is inconsistent with current knowledge on the nature of particles in volcanics clouds (e.g.; Rose et al.; 1980; Symonds et al.; 1994). What was meant was that, as in fire plumes, which are rich in soot, volcanic plumes also contain an abundance of small particles. In both cases, the small particles lead to a considerable increase in atmospheric opacity causing warming at the altitude of the cloud and cooling along the ground below the plume. We wanted to indicate the error and also emphasize that it does not affect in any way the analyses presented or any of the results. In all other respects, the paper still appears sound to the authors.