Naked Science Forum
Life Sciences => The Environment => Topic started by: @dreamcatcher37 on 05/11/2010 15:30:02
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@dreamcatcher37 asked the Naked Scientists:
How much effect does recent increased volcanic activity have on global warming & amount of pollution in the air?
What do you think?
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Volcanic explosions release massive amounts of CO2, SO2 and other compounds into the air. This has been going on since the earth was "born." It is likely that if there were no volcanic eruptions in the past 100 years global warming would be so slow in proceeding that it would be negligible. But stopping volcanic eruptions would be much more difficult than reducing the number of cars on the road and dependence on oil and coal as an energy source.
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This might help
http://www.thenakedscientists.com/forum/index.php?topic=15196.0
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Bill.D.Katt.
The net effect of volcanic eruptions is dominated by an increase of the earth's albedo in the upper atmosphere by sulfur dioxide which causes "global dimming." So if there hadn't been any volcanic eruptions in the last hundred years it would be considerably warmer.
Steve
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SteveFish, I stand corrected, thank you. I shall do more research next time.
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Bill:
If you pursue this a little you will find that a very long time ago there were periods when shifting tectonic plates resulted in subduction zones that carried crust containing a lot of fossil carbon down into the deep mantle. In these instances, volcanic action released enormous amounts of CO2 that radically heated the climate. I am not an expert in this, but came across the information I have given while looking into the science of global warming.
Steve
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SteveFish
Volcanos do produce a large amount of SO2, which does have a cooling effect on the climate because of formation of aerosols and cloud condensation nuclei, but the cooling effect lasts a short time...a few years to a decade in the case of large eruptions. The CO2 released by volcanos has a much longer residence time in the atmosphere (by one to two orders of magnitude), so it is quite possible that the net effect of absolutely no volcanic eruptions over the past hundred years would have an overall cooling effect.
One other point of order...volcanos do not produce pollution.
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Frethack:
Thanks. I am aware of the persistence of CO2 on the atmosphere, but my point was that in the last 100 years, the time period specified in Bill D. Katt's post that I responded to, most of the eruptions have primarily had a cooling effect (e.g. Pinatubo) while CO2 emissions have been relatively small in the overall scheme of things.
If recent volcanic eruptions have a net warming effect over the next several hundred years it would be relatively insignificant because in terms of both global dimming (cooling from aerosols) and global warming (from greenhouse gasses), humans have emerged as the dominant factor. Research on the earth's prehistoric past, where natural processes have been shown to have caused large shifts in climate (think major extinction events), should serve as a caution regarding how the earth's climate responds to forcing.
Steve