Posted on 12/24/2012 9:37:21 AM PST by Errant
In 1991, it was a disaster for the villages nearby the erupting Philippine volcano Pinatubo. But the effects were felt even as far away as Europe. The volcano threw up many tons of ash and other particles into the atmosphere causing less sunlight than usual to reach the Earth's surface. For the first few years after the eruption, global temperatures dropped by half a degree. In general, volcanic eruptions can have a strong short-term impact on climate.
Conversely, the idea that climate may also affect volcanic eruptions on a global scale and over long periods of time is completely new. Researchers at GEOMAR Helmholtz Centre for Ocean Research Kiel (Germany) and Harvard University in Massachusetts (USA) have now found strong evidence for this relationship from major volcanic eruptions around the Pacific Ocean over the past 1 million years. They have presented their results in the latest issue of the international journal "Geology".
The basic evidence for the discovery came from the work of the Collaborative Research Centre "Fluids and Volatiles in Subduction Zones (SFB 574). For more than ten years the project has been extensively exploring volcanoes of Central America.
"Among others pieces of evidence, we have observations of ash layers in the seabed and have reconstructed the history of volcanic eruptions for the past 460,000 years," says GEOMAR volcanologist Dr Steffen Kutterolf, who has been with SFB 574 since its founding. Particular patterns started to appear.
"There were periods when we found significantly more large eruptions than in others" says Kutterolf, the lead author of the Geology article.After comparing these patterns with the climate history, there was an amazing match. The periods of high volcanic activity followed fast, global temperature increases and associated rapid ice melting.
To expand the scope of the discoveries, Dr Kutterolf and his colleagues studied other cores from the entire Pacific region. These cores had been collected as part of the International Integrated Ocean Drilling Program (IODP) and its predecessor programmes. They record more than a million years of the Earth's history.
"In fact, we found the same pattern from these cores as in Central America" says geophysicist Dr Marion Jegen from GEOMAR, who also participated in the recent study.
Together with colleagues at Harvard University, the geologists and geophysicists searched for a possible explanation. They found it with the help of geological computer models. "In times of global warming, the glaciers are melting on the continents relatively quickly.
At the same time the sea level rises. The weight on the continents decreases, while the weight on the oceanic tectonic plates increases. Thus, the stress changes within in the earth to open more routes for ascending magma" says Dr Jegen.
The rate of global cooling at the end of the warm phases is much slower, so there are less dramatic stress changes during these times. "If you follow the natural climate cycles, we are currently at the end of a really warm phase.
Therefore, things are volcanically quieter now. The impact from man-made warming is still unclear based on our current understanding" says Dr Kutterolf. The next step is to investigate shorter-term historical variations to better understand implications for the present day.
Ice core data supports the theory that the earth’s normal climate is much colder than what we’re seeing today, and that we’re currently at the end of a typical 12K year warm period which themselves occur approximately every 100K years or so in the recent past (from 800K years of ice core data).
If we go with the theory that impacts cause glacial periods, we have to address the following:
First, is ice core data accurate and reliable?
If so, what causes the earth to warm up for 12K years after the 100K year cold period? The climate hardly knows when the asteroids/comets are due to return.
What causes the warming? Does the sun somehow “know” it’s time to warm up the planets through some yet unknown force or through transitioning certain areas of space periodically?
What are the orbits of 100K year impactors or does the solar system transition fields of periodically?
Why does the ice core data show an increase in CO2 prior to and post colder ice age entries?
One thing I have been considering: the possibility of comet ISON breaking up as it swings around the sun next year, if it makes it that far. Depending upon where a possible breakup might occur, the earth could wind up in the path of some of the debris.
It's ALL interesting food for thought! :)
Ice core data supports the theory that the earth’s normal climate is much colder than what we’re seeing today, and that we’re currently at the end of a typical 12K year warm period which themselves occur approximately every 100K years or so in the recent past (from 800K years of ice core data)... what causes the earth to warm up for 12K years after the 100K year cold period? ...What causes the warming?Use of the ice core data means the assumption that none of the ice was laid down quickly, iow, that there is a ring structure analogous to tree rings, with a stable period of accumulation.
Give me some scientific evidence (cites) to support that statement.
I don’t think the low-level dust or even pyroclastic material is the problem, rather the ejecta and/or pyroclastic material propelled into the upper reaches of the atmosphere which would cool the planet. Low level material which reduced the albedo of ice sheets would contribute to warming, high level material would decrease the amount of energy which reached the surface—and this has been known to occur on a global scale, whether driven by tectonics or an impact.
Thanks S’J’!
Why?
There is a theory out there concerning an impact in Argentina over 3M years ago that wiped out some South American species as being the last major impact, and most know about the big one North of the Yucatan that is attributed to the demise of the dinos, 65M years ago.
Likewise, really large volcano eruptions have been attributed to major losses of flora and fauna. A few came close to wiping out Homo sapiens if you can trust the work of certain researchers.
Evidence seems to support large impacts occurring over millions of years while major volcanic eruptions occur over thousands or hundreds of thousands of years. Take another look at the ice core data chart. As far as I know, the science behind its accuracy is pretty solid (please direct me to evidence otherwise).
Looking at only the last 400K years, it’s hard to miss the four unusual periods of VERY short term warming (relatively) before temperatures fall again. The odds are good that some sort of cyclical phenomenon is causing this warming. IMO, either the sun through increased output, or heat pulses from the earth’s interior (warming oceans) are the likely candidates. I don’t see how an impact would cause a warming period; much less not leave recent evidence behind, since we’re at the end of the current 12K year warm period.
“The science behind its accuracy” is the assumption that nothing has happened out of the ordinary, and that there are therefore definitive layering patterns representing individual years. In the case of the Eltanin impact (that may be what you referred to as the Argentinian impact 3M years ago, it was actually about 2M years ago, and offshore in the Pacific) laid down an iridium signal found in the ocean bed cores.
https://www.google.com/search?q=eltanin+impact+iridium
http://www.freerepublic.com/focus/bloggers/1248414/posts
The problem with *any* gradualist model for massive glaciation (the ice ages iow) is that those assume that cold will make it work, but don’t have any mechanism by which the Earth can stay cold enough that snow won’t melt but with warm enough waters that the hydrologic cycle will continue to contribute snow accumulation. This problem is why there is so much disagreement among the gradualists as to how it happened, and why the basic consensus doesn’t work, merely restates the lowest common gradualist view — that glaciation happened gradually.
My problem with CO2 and Antarctic cores is twofold — number one, despite the “lag” between higher temperatures as inferred from proxy data and the later increase in CO2 (ditto), the Antarctic core data is pointed to by the AGW propagandists (including those formerly allowed to operate on FR) as evidence that CO2 causes warming, IOW, that the studies themselves only came about due to the political seduction of the sciences; and number two, again, that they operate under the assumption that there’s been no sudden deposition of ice.
Since the conclusion is completely founded on the assumption, the conclusion can’t be pointed to as evidence of the assumption.
Iridium in the seabed means iridium may have been deposited in the lower layers of the Antarctic ice. If someone drills a 3M year core, with the dating of the core based on the gradualist assumption, they probably won’t find any iridium. Since most of the icecap was laid down at one time (or possibly in several widely spaced episodes; again, the Sun doesn’t have much time to melt miles of ice in the Antarctic, but the N Pole ice is thinner, afloat on the ocean, and melts every year in the 24 hour days of summer), the iridium concentration should be greatest near the foundation, although it could also be spread out through the entire layer that was laid down over a short interval.
Since the evidence (see the link to the FR topic for more links and info) is that Antarctica was temperate less than 3M years ago, the ice cap there can’t be 30 million years old — that 30M year figure is of course based on the continental drift model, rather than actual data from Antarctica.
Thanks again, Errant!
Because I've spent years studying the mechanisms involved in Ice Age cycles and have never heard of such a theory.
This should concern me, why?
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