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This is interesting.

Drew, large volcanic eruptions have global effects. That was seen fairly recently from the eruption of Mount Pinatubo.

 

Nobody's arguing that climate change will be the end of the world. That doesn't mean it isn't a Really Big Deal. I'd like to avoid the mass starvation, death, migration, and war that'll accompany the sort of climate shifts you've just envisioned.

Ah, yes, as to carbons sinks and stuff, this is a decent resource for the North American component.

 

I wholeheartedly agree, dmc. In fact, I would go out on a limb and say the destruction of forests worldwide (over the last few centuries) is the single greatest impact issue to global warming. There have been several articles indicating the whole 'going green' movement, in particular ethanol fuel, has had a devestating effect on global warming. Many countries are doing the slash and burn routine on rain forests to jump into the ethanol market. The loss of the trees, which reduce carbon dioxide levels, is far outweighing any benefits we get by moving away from petroleum based fuels.

Perhaps we should setup a worldwide account where oxygen production/use is the commodity. Pay countries with rain forests to keep them.

 

@T2: Yeah, many aspects of such events are global, but pretty much everything within range of the eruption died. Compared to the snuffing out entire ecosystems in a matter of hours, global temperature changes seem minor in comparison. The Yellowstone Plateau, the Teton Range, and thousands of surrounding square miles of Wyoming, Montana, and Idaho were barren and nearly lifeless after the eruption...for the third time in two million years.

 

Ah, but Drew, I'm talking lasting effects. The ash settled on the US, within a geologically miniscule amount of time, similarly for the devastation and return of local life. The gasses, however, were spread into the atmosphere in a manner that, at the least, guaranteed a more global effect than the way we're doing it now. My real question, however, is to the durration of those gasses. There is no geological record of a lasting, global climate change associated with any of those erruptions, which suggests that either, one: the gasses released had no effect, or two: the effect of the gasses released was short-term.

As for the amount, unfortunately no one was arround to measure local CO2 concentration increases but look up data on supervolcanos and compare to the Yellowstone Calderas for estimates. This is all theoretical, as no supervolcano has errupted within scientific memory, but miniature experiments show that the gasses released should reach the highest levels of the atmosphere, due to their initial velocity and the whole process that allows for this. Also, due to the process, these volcanos release much more gas relative to the ash released than a normal volcano.

Basically, what happens is this: the magma chamber starts to form just like any other volcano, but for some reason does not mannage to punch through the crust. This may be because of depth or surface material or some combination. Instead, it continues to expand horizontally, forming a massive magma chamber (somewhat larger than the resulting caldera). The pressure in the magma continues to increase. As it does so, it disolves more and more volcanic gasses into the magma, creating a very fluid type of magma. Eventually, the pressure is enough that cracks form through the crust, allowing some of the magma to be exposed to surface air pressure (significantly lower). This sudden pressure change results in explosive decompression, extending the crack, but more importantly particulating the magma due to the sudden release of all the gasses trapped in it. The magma cools in the atmosphere, creating extremely fine particles of glassy rock (on the scale of silica dust). This is all a local phenomenon to the crack and takes place within a split second (well, not the magma cooling,but..). The sudden loss of pressure there causes a similar decompression further in. As the reaction spreads, the crust over the magma chamber is no longer supported and collapses, exposing the entire magma chamber to surface air pressure. Almost the entire magma chamber particulates and is flung into the atmosphere by explosive decompression, and the collapsed roof of the magma chamber forms a caldera. Later, the magma chamber may be re-filled and the process can start all over again.

The key here is that the magma disolves massive amounts of volcanic gasses due to the extreme pressure, gasses which are all released at the moment of the explosion. Combine that with the large errupted mass in such volcanos (VEI-8, releasing more than 1,000 cubic km of material), and you may be able to make some guesses by scaling the CO2 releases of smaller volcanos, but that would just be a guess.

 

If this is true, then, isn't it a little irresponsible to say that "This erruption put several inches of ash on the east coast of the US, and released quantities of CO2 unmatched by anything other than similar super-volcanos and the massive volcanic activity that led to the Jurassic Period? After all, there is no way of knowing this and, by all accounts, the 315 billion metric tons of carbon we've released into the atmosphere since the industrial revolution could very well dwarf it several times over. In fact the amount we release in a single year could be higher.

 

Drew, relative Carbon-14 levels should give indication of that -- at least for the past 60,000 years (approximate). By your statement it is inferred we should have the lowest Carbon-14 levels in the archeological history, yet that is not the case. Therefore, there have been periods in history where there have been higher carbon dioxide levels than modern times.

 

On a related note, the Kentucky legislature is effing mad.

 

We absolutely have. We've also had global warming and ice ages before. What really worries the climatologists is the degree by which we are accelerating the process. Sure, we'll have an ice age sooner or later...but due to the rapidity and severity of the warming we are experiencing, not only will that ice age be sooner (far sooner) rather than later, but it will also be far more severe since the severity of an ice age correlates to the severity of the warming period before it...at least according to the IPCC.

 

Drew, some of the larger volcanos today have released amounts of CO2 near comprable to all of human activity since the industrial revolution, so it isn't too hard to imagine that an erruption thousands of times larger and much richer in gas release could dwarf it. Concider that Mt. Pinatubo was only 5 cubic km or erupted mass, and a VEI-8 event is defined as more than 1,000 cubic km, and that supervolcanos, being the largest known, are estimated to be WELL withing the VEI-8 range. All in all, while I don't know exact numbers, I think it's not that much of a guess.

 

That isn't actually true, although Rush Limbaugh has said it several times and even said it in one of his books (and, despite the fact that he's been debunked several times, he still says it). Since we've been measuring, we haven't had an eruption even come close to equaling our yearly CO2 output.

 

Well, this is fun.

 

I think many people become confused about the output of any volcano in general. Although carbon is one of the many elements spewing out, it is not high percentage of the overall output. Most descriptions of volcanic activity give the overall mass put out by the eruption -- the vast majority is sulfur based ash and silicon based rock.

The sulfur remains in the atmosphere for an extended period and can cause global cooling.

 

The sulpher dioxide stays in the atmosphere for a period of a few years at most, not really an extended period of time as far as this topic is concerned, but more long-term than the ash. As for the amount of different gasses, it varies from volcano to volcano, and drastically with the type of volcano and magma, but most have more CO2 than SO2. You can check out some examples here .

Sorry, Drew, but I haven't actually been able to find any actual data on the amounts of CO2 released by any specific eruptions, however I have found several sites showing the anuall release to be about 150 times less than estimated human output. Still, however, considering that the largest eruption since measuring began was only a VEI-6 (at least hundereds of times less powerful) you have to admit that there should have been some significant impact on the environment, and it should have lasted for at least 100 years from what these people are saying now.

 

NOG, I think you need to re-examine T2's post above regarding volcanic CO2 output. He made it quite clear that volcanoes don't release all that much CO2. Either you or the people running the sites where you are getting your information are very confused on this matter. To re-iterate, since we've been measuring actual CO2 output from volcanic eruptions, no single eruption has even come close to equaling our yearly CO2 output.

 

Drew, you have an issue with repeating your points without actually responding to other people. The people running the site are the USGS (United States Geological Survey) and, to quote them:

CO2 is the second most abundant gas released from volcanic systems.

Also, while no eruption since measurements began has matched human output, no eruption in recorded history has even come close to matching the power of a supervolcano. It is estimated that, on average, it would take about 8,000 more average eruptions per year to match human CO2 output today. Well, a supervolcano is FAR more than 8,000 times more powerful than an average eruption. In fact, from this site , it looks like about one hundred thousand to one million times as powerful.

 

Actually, NOG, I just missed a rather important modifier in the statement I quoted in my last post.

I read this:

But what you wrote was:

Big difference, no? I apologize for misreading your post. In my own defense, at the time I posted that, I hadn't slept in 42 hours. (I'm a shift worker)

 

Fixed.

 

My comment was about the relative mass of gasses (such as carbon dioxide) versus the mass of ash and magma put out by a volcanic eruption -- the solids released during an eruption greatly outweigh the gasses released. My observation was simply that most data regarding volcanic activity lists total mass released which would not be the same as total gas released.

The articles are quite interesting. It does show why there could be time of higher carbon dioxide levels than we see currently.