RE: Climate catastrophe isn't so certain
May 21, 2012 at 9:44 pm
(This post was last modified: May 21, 2012 at 10:55 pm by Anomalocaris.)
(May 19, 2012 at 12:04 am)Polaris Wrote: Right now we are experiencing what is a microcosm of the Permian Extinction with the excessive volcanic activity (five major eruptions a century) in the previous millennium, which had not occurred in such ferocity for millions of years.
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That's untrue. There is no evidence the eruptive frequencies of separate volcanic systems flucturate together. Major volcanic induced climate disturbances are usually caused by extraordinarily high activity in a single volcanic system, such as a single large resurgent caldera or clusters of calderas, or a single hot spot driving a single flood basalt eruption. There simply has been no such truly huge eruptions in the last century or last several tens of thousands of years.
There has only one moderately large eruption in the last 2 thousand years, but at least 4 in the 4 thousand years before that. This suggest even by coincidence, there hasn't been any significant increase in rate of serious eruptions in the last thousand years. Couple this with the fact that the biggest eruption in the last 12000 years is only a fraction of the size of a major resurgent caldera eruption, which happen roughly once every 100,000 years or so somewhere on the globe, which in turn is a tiny fraction of large basalt igneous province eruptions, which happens every few tens of millions of years somewhere on earth.
So it is hard to argue volcanic activity is currently powering any major global climate change.