Guest post by Steven Goddard
Scientific American has reported that global warming may cause an increase in volcanic eruptions, due to increased magma formation at lower pressures as glaciers melt.
This caught my attention because I used to work as a volcano researcher and igneous petrologist.
That report said that about 10 percent of Iceland’s biggest ice cap, Vatnajokull, has melted since 1890 and the land nearby was rising about 25 millimetres (0.98 inch) a year, bringing shifts in geological stresses.
They estimated that the thaw had led to the formation of 1.4 cubic km (0.3 cubic mile) of magma deep below ground over the past century.
At high pressures such as under an ice cap, they reckon that rocks cannot expand to turn into liquid magma even if they are hot enough. “As the ice melts the rock can melt because the pressure decreases,” she said. Sigmundsson said that monitoring of the Vatnajokull volcano since 2008 suggested that the 2008 estimate for magma generation was “probably a minimum estimate. It can be somewhat larger.”
Interesting theory, but does it work quantitatively? Magmas, as with most solids, do show a direct relationship between the melting point and pressure. As the pressure increases, so does the melting point. (Ice is a noticeable exception to this, and shows an inverse relationship. The reason that people can ice skate is because the pressure under the blade creates a thin later of melted ice which lubricates the surface.
Below is a phase diagram of a basaltic magma similar to that found in Iceland, showing the relationship between temperature and pressure. The melting temperature does decrease at lower pressures. From 100 km depth to 0 km the melting point drops about 300°C. That is about 3°C / km. Ice is about one third as dense as basaltic magma, so the loss of 1 km of ice lowers the melting point by about 1C, or less than 0.1%.
More precisely, this study from the Carnegie Geophysical Institute did an empirical measurement of the relationship for one basaltic mineral – diposide. They found the relationship to be
Tm = 1391.5 + 0.01297 * P
Where Tm is the melting point in degrees C and P is the pressure in atmospheres. One atmosphere pressure is equal to about 10 metres of ice, so one additional metre of ice increases the melting point by about 0.0013°C. The loss of 100 metres of ice would therefore lower the melting point by about one tenth of a degree. The thickest ice in Iceland is only 500 meters thick, so complete loss of all ice would only alter the melting point by about 0.5°C, or less than 0.05%.
The geothermal gradient of the earth is typically about 40°C per km, so a 0.5°C change in temperature is equivalent to a depth change of about 20 metres. Near mid-ocean ridges this gradient is steeper, so the equivalent depth change in Iceland would be less than 20 metres. Is it credible that a 0.5°C decrease in the melting point could stimulate excess volcanic activity? Short answer – no. Volcanic activity is caused by magma rising to the surface, not glaciers melting. However, the loss of the glaciers would reduce the amount of steam and ash generated. Ash is formed when magma is cooled and fractured by steam. So the loss of the glaciers would reduce the size of the steam/ash cloud and make the Iceland volcanoes behave more like Hawaii volcanoes.
In short, the loss of all ice in Iceland would make the volcanoes less destructive.
BTW – On Al Gore’s planet, the geothermal gradient is much higher, with core temperatures averaging millions of degrees.
http://www.youtube.com/watch?v=ag2AWst3Qv4
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ROM (02:49:44) [various “climate scientists” who were advocating all sorts of totally hare brained and potentially catastrophic global climate geo-engineering projects to “stop global warming”]
National Geographic keep broadcasting documentaries for kids about these hare brained schemes. I think we should make a list of those “scientists” and who pays them.
David Hall (03:31:27) :” If you ever tried to pick up a peice of ice that dropped out of your glass onto a hard surface, you would just ….. know that.”
Hate to wander again but ice skates blades are not flat on the bottom. They are ground into a concave surface so that the edges cut into the ice and the water from the melted ice caused by the overall pressure fills the concave area thus allowing you to move. If there were no edges it would be difficult to turn sharply or start and stop quickly. Hockey skates have a deeper concave grind and figure skates less because the requirements of what the blades need to do are different. Picking up a piece of ice with your hand that dropped out of a glass is totally different than what skates do.
Well I’m anything but surprised to see these politically ‘useful idiots’ trying to scare people with a .0005 change in the melting point of magma after they successfully managed to convince so many people that global warming itself was because of a .00002 human addition to the atmosphere.
Anthony: If anyone is in the first group to be shot under new ECO-CIDE thinking it’s you! We’re going to miss you! It’s been great fun but it was a bit silly of us to chaff at a concensus of so many…..um….so many…..I don’t know who they are.
————————————————————
Club Of Rome Behind Eco-Fascist Purge To Criminalize Climate Skepticism
Ultra elitist organization that openly bragged of inventing global warming scare to manipulate population behind new onslaught of green fascism which would criminalize questioning man-made climate change
Paul Joseph Watson
Prison Planet.com
Tuesday, April 13, 2010
The British lawyer who last week called for introducing international laws through the United Nations which would make it a crime against humanity to question the reality of man-made global warming has close ties with the Club of Rome – the ultra elitist organization which openly bragged of how it invented the climate change scare as a means of manipulating the global population to accept world government.
British lawyer-turned-campaigner Polly Higgins (pictured top) recently launched an initiative to have the UN put pressure on national governments to pass laws that would declare the mass destruction of ecosystems a crime against peace, punishable by the International Criminal Court.
Under the guise of going after big corporations and polluters for the war crime of emitting the gas that humans exhale and plants breathe, the proposal would actually target individuals and people who merely express skepticism towards man-made global warming.
“Supporters of a new ecocide law also believe it could be used to prosecute “climate deniers” who distort science and facts to discourage voters and politicians from taking action to tackle global warming and climate change,” reported the London Guardian.
Some respondents to the Guardian article agreed that merely questioning whether man-made climate change was real should be criminalized – literally calling for the establishment of a UN-run thought police that would prosecute anyone who expressed dissent against the AGW belief system.
“Would be nice if corporate-sponsored climate change denial was made an offence,” wrote one.
“Think about that lineage and possible development of a war-crimes-style trial: Come up with an issue that will fit the bill to terrify the public into accepting the strictures and governance that you demand out of fear of overpopulation (and a general control fetish), then follow that up with putting those who challenged you in the dock,” writes Planet Gore.
“I’m thinking hard, and have catalogued quite an inventory already, but must admit that this might be the best manifestation of the greens’ fascistic tendencies and totalitarian bent.”
————————————————————-
The grounding is a procedure invoked when a BA ‘four engined’ plane had a four engine simulateous flame out. They were able to descend and relight. They say By the time the pilot notices the presence of ash, it’s probably too late and so the safest thing to do is ground every thing down wind.
It may have been the Discovery Channel showing hare brained geo-engineering schemes rather than National Geographic.
Eyjafjallajokull aka Island-Mountains Glacier web cam LIVE!
http://eldgos.mila.is/eyjafjallajokull-fra-thorolfsfelli/
This is how you say “Eyjafjallajokull ”
http://upload.wikimedia.org/wikipedia/commons/1/10/Eyjafjallaj%C3%B6kull.ogg
Listen to it 100 (or maybe 1000) times and you’ll be able to say your first word in Icelandic!
http://en.wikipedia.org/wiki/Eyjafjallaj%C3%B6kull
“Eyjafjallajökull (pronounced [ˈɛɪjaˌfjatlaˌjœːkʏtl̥], translated as “island-mountains glacier”) is one of the smaller glaciers of Iceland. It is situated to the north of Skógar and to the west of the larger glacier Mýrdalsjökull.
The icecap of the glacier covers a volcano (1,666 metres or 5,466 ft in height) which has erupted relatively frequently since the Ice Age, at times bringing rhyolite to the surface.[1] The volcano erupted twice in 2010, on 20 March and 14 April. The April eruption caused massive disruption to air traffic across Northern Europe, with scientists claiming it was ten to twenty times more powerful than the March event. The most recent previous eruption was from 1821 to 1823, causing a fatal glacial lake outburst flood.[citation needed] A previous eruption was in 1612. The crater of the volcano has a diameter of 3–4 kilometres (1.9–2.5 mi) and the glacier covers an area of about 100 square kilometres (39 sq mi).
The south end of the mountain was once part of the island’s Atlantic coastline. As the sea has since retreated some 5 kilometres (3.1 mi), the former coastline has left behind sheer cliffs with a multitude of beautiful waterfalls, of which the best known is Skógafoss. In strong winds, the water of the smaller falls can even be blown up the mountain.”
eh-a-val-zel-buhKuk
is about as close as my person phonetics make it out.
This eruption might, like the last one, last for two years. Thus some worst case planning by the airline industry is in order, including design changes.
A couple that come to mind:
Filter systems for the engines. Don’t military helicopters already do this?
Abradable coatings for the windscreens and leading edges, which would need to be easily replaceable.
As an alternative, invest in cruise lines!
I recall saying a little while ago that the solution to AGW was to blow up a volcano (I think I said ‘Nuc”) and cool off the Earth a little at a time. I think someone’s taken my Einsteinian Solution and used it before I could get a good patent attorney to file my invention. I also think someone at this website is responsible for this theft and the current situation in Europe. On last count there were 42,002,317 of you who are possible suspects (minus 1 – myself of course). Each of you can expect to hear from my attorney in the near future. I fully intend to get my due.
PS: There’s a thief in our midst. Beware!
boo hoo boooo hooooo
More proof of AGW, we now have competing theories, so if volcanoes in Iceland become stronger or more frequent or less dangerous, then we can use that as proof of AGW.
Perhaps Freysteinn Sigmundsson has cause and effect the wrong way round?
It is possible that it can take many years for the magma to build up in the chamber beneath a volcano enough to trigger an eruption. During this period the bottom of the covering glacier will be heated by conduction and the ice will slowly melt.
Thanks to Steven Goddard, whom I think is right on the money.
At least somebody in the British press has it right, they pissed off an old Nordic god. http://blogs.telegraph.co.uk/finance/jeremywarner/100004999/proof-that-vulcanic-ash-comes-from-a-nordic-god/
See http://en.wikipedia.org/wiki/British_Airways_Flight_9
From this article a plane flying through a volcanic ash cloud that could not be detected by onboard instruments had the following problems:
1. The windscreen was sandblasted and the crew could not see through it.
2. Landing lights were damaged.
3. Fuel was contaminated.
4. All four engines were damaged.
The decision to ground aircraft in the UK and Europe is the sensible one.
This shows why it’s Europe and not so much Iceland whose air travel is restricted. They stopped updating Friday night, for reasons unknown.
http://www.vg.no/bildespesial/spesial.php?id=7609&o=0&katId=-1
I didn’t get a chance to see this article because, after 25 years reading SA, they turned alamist and I had to tell them to keep their glossy fish wrap out of my mail box.
I would have thought that the Earths tectonic plates are going to keep moving about with or without any surface heating or cooling, or changes in downward pressure from the surface, because all the movement is driven by the underlying currents below the earths crust. If there is an effect from a lessening downward surface pressure then I would have thought that there would be an increase in tectonic activity with a lessening of intensity.
The logic of this heavy ice argument should mean that when a volcano grows and gains mass it should switch itself off as it’s growing downward pressure increases the melting point of the underlying magma. A kind of feedback mechanism.
Anyway there’s a joke in here somewhere to do with hell freezing over.
@Steve Goddard
The century-old belief about ice skates being lubricated by the melting of ice under the blade due to increased pressure is wrong.
Explaining Ice: The Answers Are Slippery
“So the loss of the glaciers would reduce the size of the steam/ash cloud and make the Iceland volcanoes behave more like Hawaii volcanoes.”
I learned from two vulcanologists back in 1970 that there are two main types of magma, and thus volcano behavior. They have been given Hawaiian names, “a-a”, and “pa-hoi-hoi”. The former, IIRC, is placid and just runs quietly out of the volcano, forming streams of lava. The second type is the explosive one that throws ash high into the air.
Geologists to the rescue again!
A nice concise post.
This addresses the pressure-magma chamber theory, but it doesn’t address the change in the stress field, which in theory could change the ability for existing magma chambers to erupt. Not saying that it will, just that it hasn’t been quantified. It is interesting that they assume that the land rising is due to current ice loss and dismiss or never consider the possibility that it is from a) paleo-ice loss or b) inflation of a magma chaamber
“So the loss of the glaciers would reduce the size of the steam/ash cloud and make the Iceland volcanoes behave more like Hawaii volcanoes.”
I learned from two vulcanologists back in 1970 that there are two main types of magma, and thus volcano behavior. They have been given Hawaiian names, “a-a”, and “pa-hoi-hoi”. The former, IIRC, is placid and just runs quietly out of the volcano, forming streams of lava. This is the type seen in Hawaii. The second type is the explosive one that throws ash high into the air.
The only volcanos that I have seen were in Japan, and they were only the explosive type, throwing ash high into the air. Sakurajima, near Kagoshima, regularly dusted the city with ash when I was there, and sweeping up a thin layer of black dust was a morning ritual.
IanM
I’ve subscribed to Scientific American for several decades and read every issue cover to cover. Overall it’s a great source for keeping up with a broad range of the sciences. The former editor, John Rennie, was a problem in that he is not at all objective on two subjects: global warming and evolution. In those areas he adheres to dogma rather than science and is fanatical about them. We’ll have to wait and see whether his temporary replacement, which will probably become permanent, is any different. I don’t expect a marked change as the clinging to climate and evolutionary dogma are systemic problems stemming from the political, religious, and social persuasions of a large majority of professors in academia. Our university faculties have become notoriously safe harbors for positive atheists and modern day liberals. Nowhere else in the world can one find such a concentration of people holding these beliefs.
Disclaimer: I’m agnostic (weak atheist) when it comes to religion and lean libertarian when it comes to politics.
As Sgt. Joe Friday of Dragnet fame often said to witnesses he was interviewing “Just the facts, ma’amm”. I’m only interested in the facts and the fact is that climate science has turned into climate dogma where science, like Elvis, has left the building.
Symon (04:57:32) :
I often ride my bike on ice and packed snow at -20F, as it is not very slippery. But at +20F, it is extremely slippery. Ice at +20F is slippery because there is always a thin layer of liquid water on the surface.
A wide surface area hockey puck or bottom of a shoe, slide for different reasons than an ice skate – which digs into the ice. Tire chains and studs also dig into the ice and greatly increase friction, whereas a skate greatly decreases friction. Why is that?
Could it be that the missing energy could be found in the graves of Galileo, Newton, Maxwell, Bohr Einstein etc where incoming solar energy has somhow induced the remains of these scientific giants to spin rapidly around the (formerly) vertical axis?
Steve,
Your analysis of teh pressure effect on magma is complete and convincing.
However, you’re off-base on the physics of ice skating. The link you cite involving the piano wire and ice cube classic experiment (1) doesn’t really apply to ice skating directly since the pressure effects are larger due to the wire’s very tiny diameter and (2) involves other effects, primarily the rapid conduction of ambient heat to the ice cube from the warm room. When this experiment is done in a freezer, it ceases to work.
Here’s Cliff Swartz, well-known physics textbook autor on the myth:
“Ice skates experience low friction because a thin water film is
produced between blade and ice. A popular legend has it that this
effect is caused by the lowering of the melting point due to the pressure exerted by the blade. It is true that one of the unusual features of water is that it expands during freezing. Consequently, if we prevent the expansion by increasing the pressure, we prevent the freezing and
thus lowwer the melting point. The usual pressure-temperature diagram
for water shows the boundary line between solid and liquid arching back to the left from the triple point. However, the actual effect is very small.
The slope of the boundary line is -(1.2×10^7 N/m^2/C) It would take an
increase of 120 atmospheres to lower the melting temperature 1 Celsius
degree. For the typical skate blade, the area is 27 cm x 4 mm = 11 cm
If the full weight of a skater with mass 65 kg is exerted on one blade,
the increased pressure would be about 6 atm. Sharpening the blades
does not decrease the contact area appreciably, since the blade sinks
down into the relatively soft ice.
What does produce the water film between blade and ice? There are two
plausible explanations. When the leading edge of a blade strikes the
ice, the resulting friction energy can melt a trail for the rest of the
blade. A more important effect stems from a phenomenon first noticed
by Faraday and then largely ignored because it was not understood.
We now know that at the interface between ice and air there is a thin
film of water. The thickness increases from monomolecular to several hundred molecules as the temperature rises from -10 to 0 C. Since the
reduction of friction depends on the the water film, you might conclude
that the fastest skating could be done on ice close to the melting point.
However, warm ice is soft ice, allowing the blades to sink in more. On
the other hand, cold ice, which is hard, has only a thin film of surface
water. These two competing effects yield a minimum of friction for
speed skating at about -7 C. (For further details. see James White, The
Physics Teacher, 30, 495 ((1992)).”
Just FYI.
Great job in debunking a stupid idea. Can you submit this as a letter to the editor? At least send a copy to the idiot that wrote the story.