Innovating out of global warming

[glatt]

Originally Posted by JerryM

My very serious doubt is . . . WHY!?
When one volcanic eruption releases a larger dose of "greenhouse gases" than the human race has generated during its entire existence, it should be obvious that our effect is minimal.

I've heard this "fact" often in discussion about global warming but never seen a citation to it. Often this "one volcanic eruption" is attributed to Mt. Pinitubo in the Philippines. I'd really like to see a citation.

I went looking for one, and the only thing I could find (through a link from Wikipedia) is this U.S. Geological Survey webpage which contradicts what you say.

Comparison of CO2 emissions from volcanoes vs. human activities.
Scientists have calculated that volcanoes emit between about 130-230 million tonnes (145-255 million tons) of CO2 into the atmosphere every year (Gerlach, 1999, 1992). This estimate includes both subaerial and submarine volcanoes, about in equal amounts. Emissions of CO2 by human activities, including fossil fuel burning, cement production, and gas flaring, amount to about 22 billion tonnes per year (24 billion tons) [ ( Marland, et al., 1998) - The reference gives the amount of released carbon (C), rather than CO2.]. Human activities release more than 150 times the amount of CO2 emitted by volcanoes--the equivalent of nearly 17,000 additional volcanoes like Kilauea (Kilauea emits about 13.2 million tonnes/year)!