Carbon dioxide emissions from Deccan volcanism and K/T boundary Greenhouse Effect
Ken Caldeira & Michael R. Rampino
Warming induced by CO2 output from Deccan traps volcanoes has been proposed as a possible cause for the end-Cretaceous mass extinctions. Here, using predictions of the amount of CO2 produced by the area and the effect that it would have on climate, it is shown that Deccan traps volcanism would have too small of an effect on climate to have played a major role in the extinctions.
A greenhouse warming caused by increased emissions of carbon dioxide from the Deccan Traps volcanism has been suggested as the cause of the terminal Cretaceous extinctions on land and in the sea. We estimate total eruptive and noneruptive CO2 output by the Deccan eruptions (from 6 to 20 x 10^16 moles) over a period of several hundred thousand years based on best estimates of the CO2 weight fraction of the original basalts and basaltic melts, the fraction of CO2 degasses, and the volume of the Deccan Traps eruptions. Results of a model designed to estimate the effects of increased CO2 on climate and ocean chemistry suggest that increases in atmospheric pCO2 due to Deccan Traps CO2 emissions would have been less than 75 ppm, leading to a predicted global warming of less than 1 degree C over several hundred thousand years. We conclude that the direct climate effects of CO2 emissions from the Deccan eruptions would have been too weak to be an important factor in the end-Cretaceous mass extinctions.