A widely believed myth is that volcanic activities during the last few hundred years contributed
more to greenhouse gases than all the industrial emissions put together.
By far the greatest volcanic eruption occurred in 1883 on Pulau island in Indonesia when the Krakatao volcano propelled ash to a height of 50 miles in a tremendous explosion.
The volcano threw almost 5 cu miles of rock fragments into the air ; the explosion could be heard 2,200 miles away in Australia and a tsunami waves up to 120 ft heigh took 36,000 lives in nearby coastal towns, and were recorded as far away as South America. The volcanic dust drifted several times around the earth, causing spectacular sunsets through the following year.
And yet, the atmospheric concentrations of CO2 derived from ice cores show only a small spike in a steady upwards curve of CO2 concentrations towards the present day. As spectacular as the Krakatao explosion was it is dwarfed by the combined industrial emissions at least as CO2 concentrations are concerned.