Volcanoes and Global Climate Change?

[jon-mullen]

I have yet to see one credible study links global warming with volcanic eruptions maybe the other direction.

Thank you! I'm so glad someone went and said this because I wanted to really badly, but you know, when you list your location as Kentucky you worry people naturally kind of assume you gloss over parts of your Thermo book that don't match your (presumed) political world view...anyway...

So why are people connecting volcanoes (and I guess we might as well throw in the recent bout of earthquakes) with global climate change? Is there any reason to believe they're connected? Has a single geologist made this connection?

My 2c: to make that assumption without any data makes about as much sense as connecting zombie attacks and global warming. Just my 2c, I'm mostly interested to see why people jumped to the conclusion so quickly...

[autogyro]

If anyone on earth believes that volcanic eruptions do not effect the temperature of the earths atmosphere and the level of Carbon Dioxide, all I can say is that they should study a lot harder on the subject.
Global warming is not just man made of course, however there is plenty of data to conclude that human activity has had a large effect mainly from the beginning of the industrial age to date.
The period when greedy oil companies burnt off well gas at the well heads and totaly wasted it before they found a market for it was probably the one biggest human input of CO2 to global warming. I doubt there are any figures for it, at least not in America.
It is true that the volcanos in Iceland erupt in regular cycles.
However the ice sheets are also receeding and the pressure from them is reducing over an area of mid Atlantic trench, where sea bed spreading causes magma release.
These geological factors are linked.
It gives the weak comfort to deny global warming and continue to rape the world of fossil fuel and other resources, some political ideals are even based on this. It makes absolutely no difference if global warming is partly man made. The truth is much simpler than that. If humans do not begin to live in a better balance with the earth and start to save resources and work in harmony instead of greed, a disaster will happen in the future much worse than anything humans have ever seen before and they will have absolutly no answer to it.
It is just a matter of time and the more populated the world gets the smaller the disaster needs to be to cause real human suffering.

[jon-mullen]

If anyone on earth believes that volcanic eruptions do not effect the temperature of the earths atmosphere and the level of Carbon Dioxide, all I can say is that they should study a lot harder on the subject.

Right, right, no, I'm sure putting all that ash into the air does something, I'm talking about people claiming

Cause: global climate change
Effect: volcano eruptions

[autogyro]

If anyone on earth believes that volcanic eruptions do not effect the temperature of the earths atmosphere and the level of Carbon Dioxide, all I can say is that they should study a lot harder on the subject.

Right, right, no, I'm sure putting all that ash into the air does something, I'm talking about people claiming

Cause: global climate change
Effect: volcano eruptions

Industrial activity creates higher levels of CO2.
Higher levels of CO2 from what ever source causes global warming
(atmospheric temperature change)
Higher Arctic temperatures accelerate ice melting.
Ice melting reduces the weight of the Artic ice sheets on the mid Atlantic trench.
The reduced pressure results in an easier route for magma through the earths crust.
These are atmospheric and geological facts.

[casper]

volcanic ash dispersed in the atmosphere as more greater effect - bocks suns radiation, consequently promoting global cooling, called the albedo effect, http://environmentalism.suite101.com/ar ... -eruptions

Natural decomposition of plants and cows' fart produces methane, which is 20x more effective in trapping heat. http://www.epa.gov/methane/

[jon-mullen]

Industrial activity creates higher levels of CO2.

Dig.

Higher levels of CO2 from what ever source causes global warming

Right.

(atmospheric temperature change)

Say word.

Higher Arctic temperatures accelerate ice melting.

Uh-huh.

Ice melting reduces the weight of the Artic ice sheets on the mid Atlantic trench.
The reduced pressure results in an easier route for magma through the earths crust.
These are atmospheric and geological facts.

Sounds reasonable. A little simple and conveniently timed, but reasonable. It doesn't help me that the only place online I see people saying it's global warming is the Huffington Post, while Discovery Magazine says global warming may one day affect volcanoes but today's not definitely the day, and a slew of conservative sites say it will never affect volcanoes. It's so sad that science has become so politicized...

[autogyro]

I agree it is conveniently timed to the latest eruption and the disruption to air travel.
It is correct science though.
To be fair the eruption in Iceland is nothing unusual and Global warming is not the main factor connected to it.
This is the vulnerability to natural disasters of the modern over populated human race. Reliance on air transport to the level of today can only result in major problems in the future.
It is our naive expectations that modern science and technology has all the answers, when the truth is that the earths natural power is far far more powerful than anything we can do.

[ReubenG]

Ice melting reduces the weight of the Artic ice sheets on the mid Atlantic trench.

I had the problem with the above statement explained to me in the following way:
Consider a glass of water, with ice cubes floating at the top. The pressure at the bottom equals the weight of the contents of the glass divided by the base area. Then allow the ice cubes to melt. Does the pressure at the bottom of the glass change?
Assuming no evaporative loss, the number of water molecules in the glass does not change, therefore the weight does not change therefore the pressure does not change.
Does the height of liquid in the glass change? Also no. The ice (of lower density than the water) displaces a volume of liquid water equal to its own mass. (Due to the lower density of ice, a small portion floats above the surface) So when the ice melts, its density becomes equal to that of the liquid water and the mass of ice now occupies the same volume of water that it originally displaced. Hence no change in height of liquid.

The Artic ice sheets float on top of water - they only encroach on the earth's crust around the coast of Greenland and parts of Canada and Russia. So the Artic ice sheets are analogous to the ice in a glass of water - melting them does not change the pressure at the bottom of the ocean (glass) or the level relative to the coast line.

I disagree with the assertion that melting Arctic ice sheets reduces pressure at bottom of the ocean - regardless on the effect of ocean floor pressure on volcanic eruptions.

Having made the above statements which probably upset the environmentally conscious, I am going to come down on the side of the greens. While my assertions above are true for ice floating on water, there is a very large mass of ice resting on top of land (Antarctica) and the entire northern coastlines of Alaska, Canada, Scandinavia and Russia. Increasing global temperatures (for what ever reason) will cause some of this ice to melt and flow into the oceans, increasing the mass of water in the oceans - thereby increasing sea levels and ocean bottom pressures.

I completely agree with Autogyro's opinion that humanity does not have a balanced account with nature, and that we need either a significant change in consumer behaviour, or the human population on earth, to correct the balance.

[autogyro]

Iceland has large areas of ice sheets over its land mass and glaziers.
Many Icelandic volcanoes have ice caps.
The earths crust is very thin in this area and any change in the pressure on the crust effects the capability of magma to reach the surface.
I agree that there is little data to calculate how much the current eruption has been effected by a reduction in ice mass. It is after all, a very small volcano, (which is worth remembering).
However, the process is happening and the more ice that melts the more likely this will help to cause a much bigger eruption.

[autogyro]

I completely agree that ice sheets over sea water do not increase pressure on the sea bed, I will remember your post and my old tutors comments on density and specific gravity next time I have a bath and shout Ureka or decide to design another sailing boat.
What this melting ice over sea does, is potentialy much worse. It releases fresh water right into the path of the Gulf Stream. At present it sinks beneath and the Gulf Stream continues to flow North and East to warm the top edge of Europe.
If the cold fresh melt water increases above a certain level it will stop or reverse the Gulf Stream and England and Western Europe will suffer a major reduction in temperature. Not exactly what some people think global warming is about is it, a mini ice age.
Do I then share the veg from my allotment with the motor head with atitude and a huge 4x4 gas guzzler up the road when this happens, or do I let the ba--- starve.

[Ciro Pabón]

If this were Wikipedia, I would have put an "Original Research" tag.

Hot spots are caused by plumes that come from deep inside the mantle... sigh. If someone could be as kind as to point us to a source that claims that ice melt will cause volcanoes to erupt, I'd be glad to hear that.

Size of Hekla ice cap:

Am I wrong or you can see the rocks beneath the ice? How much does the ice weight? FYI, the source of the mantle plume that creates Hekla is 6 km under the surface and 6 km of rocks weighs... mmmm.... like 1.500 times what 10 meters of ice weighs


BTW, Hekla is a few miles north of the unpronounceable volcano that paralyzed flights over Europe and the source of the largest eruption in the last millenia (8 km3).

On the other hand (damn, science forces you to be neutral, how I hate that ) it is a well known fact that seeping water causes the melting point of rocks to change. That's why the mantle erupts along faults. However, see ReubenG's objection.

[autogyro]

http://www.freerepublic.com/focus/news/2494924/posts
Best I could find. I think it proves the point.
The crust may be 8 to 10 KM thick at this point in Iceland but the weak fisures to the surface through the crust are constantly being pulled apart from the effects of seafloor spreading and the mantle plumes often extend close to the surface If they do not reach the surface and cool they form basalt inclusions.
Obviously just before an eruption the magma has got to be close to the surface so your argument about the weight and depth of solid rock is untenable.
Even a small ice cap on a volcano weighs many thousands if not millions of tons.
Removing this weight from a volcanic vent will have an effect on the capability of the magma to reach the surface. The basalt flows in this region are not in themselves explosive, it is when the molten magma comes into contact with water or ice that it becomes explosive. Under water or under ice eruptions are common and regular.

[Miguel]

I'm with Ciro in this one. Although Autogyro's argument is of course plausible, I have a hard time believing that some changes in the ice cover can have a readily observable effect in eruptions.

On the other hand, those eruptions may as well depend on some very complex equilibrium, and a variation of 0.1% of the pressure will cause measurable effects. But what do I know. For me, 300 and 310 GPa are basically the same thing.

[noname]

http://brneurosci.org/co2.html

[Miguel]

http://brneurosci.org/co2.html

Oh, well. I just woke up, and my sc carbon Fermi surface calculations are done. So I am in a bit of a mood toda and even though I am paid to perform structure prediction, I might enjoy this.

Anyway, because I'm not payed to do this, I ignored mostly everything but the title and the conclusions. In the conclusions you can read the following phrase: "the IPCC's predictions of catastrophic temperature increases produced by carbon dioxide have been challenged by many scientists". Sic. No quotes. No references. No substance.

Do you want substance? Let's talk about scientific consensus, with some figures [1].

-From 1 (strongly disagree) to 7 (strongly agree): How convinced are you that climate change, whether natural or anthropogenic, isoccurring now?

Average answer: 6.4 +-1.0. Median answer: 7 (67%).

-How convinced are you that most of recent or near future climate change is, or will
be, a result of anthropogenic causes?

Average answer: 5.7 +- 1.4. Median answer. 7 (34.5%)

If you have a look at my *reference* [2], you will see climatologists' professional opinion on their tools, other than politics. I see it as a pretty honest survey. And of course some people doubt climate change. Heck, I also know a theoretical physicist that is completely convinced that the electron spin can be explained from a classical viewpoint. But then again, I suppose some people want to argue that if you add some heat to a body, it won't get hotter. Note: this violates thermodynamics, which is the truest lie I've ever seen.

[1] Dennis Bray and Hans von Storch (2009). "A Survey of the Perspectives of Climate Scientists Concerning Climate Science and Climate Change".

[2] Unlike many journalists, you will see that true scientists base the statements they publish in either maths or references.

EDIT: I have this link for the others: http://scienceblogs.com/illconsidered/2 ... ceptic.php