A commonly expressed argument against human-induced global warming is that

A single eruption the size of the Mt. St. Helens eruption released more of these [greenhouse] gases, dust and ash into the atmosphere than all such emissions by human activity since the beginning of recorded human history. And there are numerous volcanic eruptions yearly.

I got that from an article called Man-Made Global Warming Hoax. I could have gotten it from many places, and have seen it used a number of times by people commenting on other blogs when the topic of climate change comes up.

But it isn’t true.

According to the US Geological Survey:

• annual volcanic production of CO₂: 130-230 million metric tons
• annual human production of CO₂: 22 billion metric tons
• therefore human production of CO₂ is at least 100 times greater than volcanic production
• It would take “17,000 additional volcanoes like Kilauea” to emit the amount of CO₂ produced by human activities.

The USGS article is called Volcanic Hazards and their Effects.

No matter what side of the argument we are on, we need to be careful of our facts. My advice is to document every source, and to not say anything without knowing where it comes from.

Grace and Peace