Climatic and environmental changes are now widely recognized as the main cause of mass extinctions. Global warming that immediately preceded the Cretaceous-Tertiary boundary is regarded as a consequence of CO₂ released during the main phase of Deccan Trap emplacement. Modeling has shown that such global warming cannot be explained by the continuous release of volcanic carbon dioxide. In the present paper, we use a biogeochemical model, coupled to a climate model, to further our understanding of climate changes caused by continental flood basalts. The response of the global climate–carbon-cycle system to sulfur dioxide (SO₂) and carbon dioxide...