Are volcanoes really responsible for large levels of carbon dioxide ?

The combustion of one gallon of gasoline (octane) will replace 21.6 pounds mass of oxygen with 19 pounds mass of carbon dioxide introduced into the atmosphere.

We humans combust approximately 500 billion gallons of gasoline each year. This results in the atmospheric exchange of 5.2 billion tonnes of oxygen with 4.3 billion tonnes of carbon dioxide yearly. Add to this figure the 2.4 billion tonnes of carbon dioxide we humans respirate on an annual basis. Altogether, we humans are responsible for the production of 6.7 billion tonnes of CO2 per year via respiration and transportaion.

According to the US Geological Survey, volcanoes release more than 130 million tonnes of CO2 annually.

The human production of carbon dioxide from respiration and gasoline combustion is 50 times the amount released by volcanoes.

It is 30 Deg F here at 12:51 am on January 6, 2007. There is no snow cover on the ground.