Although vulcanicity is seen as a possible mechanism of climatic change, under present rates of eruptions it is difficult to envisage volcanic activity acting independently of other factors in causing significant and lasting global climate changes. This note considers the global plate-tectonic regime which may have prevailed during the Archean, and which, as a consequence, should have resulted in rates of volcanic eruptions significantly higher than at present. From this would follow atmospheric CO2 levels significantly higher than those which prevail today. In this note we attempt to establish a link between the Archean global plate-tectonic regime and the high atmospheric CO2 levels which are thought to have existed at that time.