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Post by marchesarosa on Apr 8, 2011 4:24:33 GMT 1
Deep-Sea Volcanoes Don’t Just Produce Lava Flows, They Also ExplodeBy Science Daily Between 75 and 80 per cent of all volcanic activity on Earth takes place at deep-sea, mid-ocean ridges. Most of these volcanoes produce effusive lava flows rather than explosive eruptions, both because the levels of magmatic gas (which fuel the explosions and are made up of a variety of components, including, most importantly CO2) tend to be low, and because the volcanoes are under a lot of pressure from the surrounding water. Over about the last 10 years however, geologists have nevertheless speculated, based on the presence of volcanic ash in certain sites, that explosive eruptions can also occur in deep-sea volcanoes. But no one has been able to prove it until now. By using an ion microprobe, Christoph Helo, a PhD student in McGill’s Department of Earth and Planetary Sciences, has now discovered very high concentrations of CO2 in droplets of magma trapped within crystals recovered from volcanic ash deposits on Axial Volcano on the Juan de Fuca Ridge, off the coast of Oregon. These entrapped droplets represent the state of the magma prior to eruption. As a result, Helo and fellow researchers from McGill, the Monterey Bay Aquarium Research Institute, and the Woods Hole Oceanographic Institution, have been able to prove that explosive eruptions can indeed occur in deep-sea volcanoes. Their work also shows that the release of CO2 from the deeper mantle to Earth’s atmosphere, at least in certain parts of mid-ocean ridges, is much higher than had previously been imagined. Given that mid-ocean ridges constitute the largest volcanic system on Earth, this discovery has important implications for the global carbon cycle which have yet to be explored. This research was funded by: R.H.Tomlinson, GEOTOP, and J.W. McConnell Memorial Fellowships; the David and Lucille Packard Foundation; and the Natural Sciences and Research Council of Canada (NSERC). www.sciencedaily.com/releases/2011/03/110328151734.htm
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Post by marchesarosa on May 17, 2011 19:09:17 GMT 1
From Catherine Brahic in the New Scientist 2007 www.newscientist.com/article/dn12218The true extent to which the ocean bed is dotted with volcanoes has been revealed by researchers who have counted 201,055 underwater cones. This is over 10 times more than have been found before. The team estimates that in total there could be about 3 million submarine volcanoes, 39,000 of which rise more than 1000 metres over the sea bed. "The distribution of underwater volcanoes tells us something about what is happening in the centre of the Earth," says John Hillier of the University of Cambridge in the UK. That is because they give information about the flows of hot rock in the mantle beneath. "But the problem is that we cannot see through the water to count them," he says. Satellites can detect volcanoes that are more than 1500 m high because the mass of the submerged mountains causes gravity to pull the water in around them. This creates domes on the ocean's surface that can be several metres high and can be detected from space. But there is a multitude of small volcanoes that have gone undetected. The only way of identifying them is to manually find their outline on sonar measurements taken from ships. Since the late 1960s, research vessels have been criss-crossing the oceans using sonar instruments to measure the depth of the ocean floor. They have generated 40 million kilometres of linear profiles showing the topography of the ocean bed between 60° North - the latitude of southern Alaska - and 60° South - corresponding to the tip of Patagonia. But until now, no one had been able to sift through them all. So, Hillier and a colleague designed a computer programme that was able to analyse the huge amount of data and identify volcano-like shapes in the sonar lines. The programme found 201,055 volcanoes over 100m tall. Previously, satellite data had identified 14,164 volcanoes over 1500 m high. Hillier then extrapolated the data to estimate how many volcanoes exist beyond the areas the research vessels sounded out. He estimates there are about 39,000 volcanoes that are higher than 1000 m, leaving nearly 25,000 yet to be directly discovered. Hiller says he was surprised to find that the density of small volcanoes dropped in the area around Iceland, as Iceland is known to be a hotspot for volcanic activity. Another surprise was that he found fewer volcanoes on the seabed around Hawaii, another volcanic hotspot. He says his findings may mean that researchers need to re-assess their understanding of how submarine volcanoes are formed. In 2006, a team of researchers from Japan discovered a new type of volcano which also defied conventional theories of volcanism. The "petit-spot" volcanoes, aged between one to eight million years old, did not sit at tectonic plate boundaries or over volcanic hotspots (see New type of volcano fires imaginations). Journal reference: Geophysical Research Letters (DOI: 10.1029/2007GL029874) ---------- If the Earth's internal central heating system contributes to the Earth's ocean temperature (it MUST, surely?) where does that leave the so-called "radiation budget" between incoming and outgoing heat? There is a deafening silence on this (to me) very interesting matter from climatologists. Why?
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Post by marchesarosa on May 23, 2011 15:36:53 GMT 1
If the underwater hydrothermal vents are introducing as much or more CO2 into the atmosphere via ocean outgassing as anthropogenic sources of Co2 where does that leave the AGW hypothesis?
Is this source of CO2 included in the calculations that blame mankind for so-called climate change?
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Post by marchesarosa on May 23, 2011 17:17:20 GMT 1
Average depth in feet ........................ Area in Million Sq Miles Pacific .........15,215 ............................ 64 million Atlantic ...... 12,881 ............................ 33 million Indian .........13,002 ............................ 28 million Southern .... 15,000 .............................. 8 million Arctic ........... 3,953 .............................. 5 million I posted these comparative figures a couple of years ago elsewhere. I stated then that the Arctic Ocean is a relatively shallow almost landlocked "basin". There is known volcanic activity under the Arctic Ocean. Is anyone AT ALL calculating the contribution of super-heated water from volcanic sources to the condition of the Arctic sea ice? If not, why not? Is this not an interesting "natural" variable that needs to be quantified? Some links on these matters here www.iceagenow.com/Ocean_Warming.htm
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Post by StuartG on May 23, 2011 21:55:40 GMT 1
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Post by speakertoanimals on May 24, 2011 19:34:44 GMT 1
From a geological point of view, current volcanism is a drop in the bucket compared with the sort of volcanism we had in the past when climate went whanging all over the shop (e.g., deccan traps). current estimates are that volcanism accounts for only a hundreth of the CO2 compared to human activity.
As regards heat flow, the amount lost by the earth is computed as an average anyway, although obviously concentrated along mid-ocean ridges, mantle plumes etc. We KNOW it is jolly patchy.
If you want to worry about the global carbon cycle, don't forget what happens at subduction zones, because despite all the energetic creation of ocean crust, as much gets subducted back in again.
Oceanic crust also seems to take up carbon as it ages:
although recent results may change the net result slightly, the point is that you have to keep in mind BOTH sorts of processes to get a proper answer, and that is what people have been doing.
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Post by marchesarosa on May 25, 2011 2:05:58 GMT 1
Yes, I've been fobbed off with that sort of silly number before, STA. I don't believe it. Do you? The annual addition of human caused CO2 to the atmosphere in ppm is trivial. And the output from undersea volcanoes is unknown. "we cannot see through the water to count them".
Do you know different?
Only a small difference in the amount of CO2 attributed to the various sources has to affect the AGW alarmist scenarios. I'm not convinced we have the full picture of either sources or sinks.
I am similarly curious about the heat generated from the Earth's interior nuclear furnace. That has to affect the global "energy budget", too. Not ALL Earth's heat comes from the sun, after all. Some, at least, comes from inside. How much and what is the impact on the purported "equilibrium" temperature of the planet and the "greenhouse"?
I'm not at all surprised that the IPCC's dominant clique doesn't want to know about the climatic effects of these unknown inputs. First they upset the tidy AGW apple cart and secondly they are bloody hard to investigate!
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Post by nickrr on May 25, 2011 6:48:49 GMT 1
Wrong. Since 1980 the level of CO2 in the atmosphere has risen from around 350 ppm to about 390 ppm. This is not trivial. Furthermore we know that the bulk of this increase is almost certainly due to human activity: www.realclimate.org/index.php/archives/2005/06/how-much-of-the-recent-cosub2sub-increase-is-due-to-human-activities/On this vulcanism stuff, the key point is that whatever the emissions are from undersea volcanoes, there is no evidence that it has changed recently. It cannot therefore explain the recent increase in atmospheric CO2 (which is unnecessary anyway as we we already have an explanation).
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Post by marchesarosa on May 25, 2011 10:04:03 GMT 1
I have not argued that the bulk of the INCREASE in atmospheric CO2 is not down to fossil fuel emissions, nickrr. I have said it is trivial in comparison to the whole. Do you undertstand the distinction?
You are talking off the top of your head. Since when was a scientist satisfied with a fob off like this? We do not KNOW what the amount of CO2 from vulcanism is nor whether it has changed. You're spouting ideology as a substitute for investigation of a known i.e REAL phenomenon and source of CO2 and ocean heat. Just because it is hard to measure is no reason to dismiss it.
The catastrophic Anthropogenic Global Warming hypothesis is based on supposedly measured temperature variation of tenths of a degree over a century and changes of CO2 from manmade sources of ca. one part per million per year. If any of these miniscule estimates are different because of unaccounted for heat and CO2 from undersea vulcanism it affects your pet hypothesis.
You should not close your eyes to this no matter how convenient blindness is for your agenda. It makes you look silly, apart from anything else. Others with genuine scientific curiosity most certainly will not close their eyes to it and you will be fighting a perennial rear-guard action to try and close down the debate. I would suggest that this is not the position someone of scientific integrity should adopt.
Did you also pooh-pooh Svensmark's GCR cloud seeding hypothesis now being tested? I bet you did!
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Post by nickrr on May 25, 2011 19:30:22 GMT 1
I think that you need to remind yourself of the meaning of trivial. A rise of 50ppm from 340 is not trivial.
No, I'm talking about what is known, and there is no known evidence of an increase in undersea vulcanism. If you think that there is, give us the evidence. You can always keep dreaming up more reasons why the rise in CO2 is not due to human activity but unless there is supporting evidence it's just idle speculation.
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Post by rsmith7 on May 25, 2011 21:51:50 GMT 1
She isn't arguing that the rise in co2 isn't largely down to human emissions, nick. I'd argue that the effects of a 50ppm rise in co2 are unknown and very probably trivial - if not beneficial. The empirical evidence, so far, supports my position.
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Post by marchesarosa on May 25, 2011 22:40:15 GMT 1
What makes nickrr think that 280ppm or 350 ppm is the perfect and essential Goldilocks level of CO2 for the planet?
Defend that position please. Let's get your assumptions and justification for them out into the open.
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Post by nickrr on May 26, 2011 18:49:50 GMT 1
There is no specific "Goldilocks" level of CO2. It's varied greatly over the earth's history. However, current human civilization is adapted to levels around 280 ppm. If this changes dramatically and the climate changes then we are likely to find all sorts of changes that will cause us problems - for instance rain patterns may change so that it's not falling in the right places for human agriculture, sea levels may rise, jeopardizing cities which are built at sea level etc etc.
The earth will survive anything we throw at it. However we may find the changes cause us a lot of problems.
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Post by marchesarosa on May 26, 2011 20:19:31 GMT 1
We will have to adapt then, won't we? We're a clever, adaptable species.
But so long as the AGW arguments are peppered with mays, ifs, likelys, possibles and coulds etc you'll forgive me if I don't start panicking yet.
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Post by StuartG on May 26, 2011 20:30:50 GMT 1
Here You are Nickrr, a video with a sensible approach... marshall.org/video/100514-climatescience.php"current human civilization is adapted to levels around 280 ppm" who says? Even I can put forward a supposition, so here goes. The areas around and in the rainforests are far higher in CO2. Wildlife seems to manage just fine. [until they chop the forests down] Cheers, StuartG look at the video...
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