Global Warming "Volcano" argument...help needed

[Flarney]

Whenever I'm talking to global warming deniers they usually trot out the "volcano" argument as their trump card. It goes something like "when a volcano erupts it spews a thousand times more CO2 and other greenhouse gasses into the environment than humans ever could" or some such. Does anyone have a link handy that debunks that?

I know it's bunk, I just don't know how to argue it...I need some ammo. :-)

The obvious argument is that we've always had volcanoes, but have only been burning fossil fuels for ~150 years, which charts closely to the rise in CO2 levels and average temperatures, so the Earth could obviously handle volcanos...

Thanks!

[trotsky]

1. Found this site:

http://www.geology.sdsu.edu/how_volcanoes_work/climate_effects.html

Volcanic eruptions can enhance global warming by adding CO2 to the atmosphere. However, a far greater amount of CO2 is contributed to the atmosphere by human activities each year than by volcanic eruptions. Volcanoes contribute about 110 million tons/year, whereas other sources contribute about 10 billion tons/year. The small amount of global warming caused by eruption-generated greenhouse gases is offset by the far greater amount of global cooling caused by eruption-generated particles in the stratosphere (the haze effect). Greenhouse warming of the earth has been particularly evident since 1980. Without the cooling influence of such eruptions as El Chichon (1982) and Mt. Pinatubo (1991), described below, greenhouse warming would have been more pronounced.

[Phredicles]

2. For starters, major volcanic eruptions are relatively rare.

On the other hand, human-generated emissions are constant (just something off the top of my head).

[hobbit709]

3. Volcanos also

spout off sulfur dioxide and ash which blocks sunlight. See "Year Without A Summer"-1815-16 aftor the Mt. Tambora eruption. A large volcanic eruption causes global cooling

[Homer12]

4. Cooling Instead

Actually, when volcano's release particles into the atmosphere, they have a tendency to block out solar radiation from hitting the earth. This has a cooling effect on the climate.

Also, Volcano's are a natural part of the carbon sink and of the climate system. Where as people releaseing more carbon into the atmosphere is not at a natural rate. Thus adding more to the system than it can re-absorb.

[NMDemDist2]

5. here ya go....

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)!

http://volcanoes.usgs.gov/Hazards/What/VolGas/volgas.html

[Flarney]

6. Awesome, thanks all!!!

[jpak]

7. Ignorant RW claptrap

Each year marine and terrestrial respiration releases ~120 Pg (10^15 grams) of carbon to the atmosphere...

and each year marine and terrestrial photosynthesis removes ~120 Pg of carbon from the atmosphere.

On an annual basis, these processes are closely balanced and result in little net increase or decrease in atmospheric CO2 concentrations.

Each year volcanic activity releases ~0.1 Pg of carbon (as CO2)...

...which is balanced by the burial of carbon in marine sediments (~0.1 Pg C per year).

Large volcanic eruptions are an insignificant source of CO2.

CO2 concentrations are increasing because human activities release ~7 pG of CO2 to the atmosphere each year. Half of this remains in the atmosphere, the rest is sequestered in the ocean or terrestrial environment.

Source: W.H. Schlesinger (1997) Biogeochemistry: An Analysis of Global Change, 2nd ed., Academic Press.

[Odin2005]

8. It's an ignorant argument.

Such arguments, IMO, is the result of too many weather disaster shows that talk about how "wimpy" humanity is compared to nature. People get this idea in thier heads that nature is so "huge" we can't affect it.