Volcanos in Gakkel Ridge NOT responsible melting the Arctic ice
July 10, 2008I am not only a global warming skeptic, but a skeptic in general. I call ‘em as I see ‘em.
There have been some attempts to link the arctic sea ice loss of the last several years to reports of volcanoes under thousands of feet of water in the Gakkel Ridge,
The truth is that all the energy from a volcano the size of Mount St. Helens could only melt 100 square kilometers of three meter thick ice. This is a trivial amount of ice for the arctic region, which typically oscillates between about 4 million and 14 million square kilometers every year. 100 square kilometers is only one hundred thousandth of the yearly change in Arctic sea ice extent
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Arctic region showing the location of the Gekkal ridge. This Google Earthimage, with annotation by Moriarty, obviously does not show the arctic sea ice.
Let’s do some simple math to work this out:
First, how much energy is released by a volcano? Of course, if varies greatly, but we just need an order of magnitude approximation for now. A common estimate for the energy released by the Mount St. Helens explosion is 24 megatons, where a megaton is supposed to be equivalent to the energy released by a million tons of TNT. A joule is the basic SI unit for energy, and one megaton is equal to 4.2 million billion joules (4.2e+15 joules). Therefore the 24 megatons released by Mount St. Helens translates into about 100 million billion joules (1.0E+17 joules). That is:
(4.2E+15 joules/megaton X 24 megatons = 1.0E+17 joules).
So now the question is: how much ice could be melted by 100 million billion joules of energy? It takes about 4 joules to heat one gram of water by 1 degree C. But it takes many more joules to melt a gram of ice. The amount of energy needed to melt a gram of a solid to a liquid is called the “heat of fusion.” The heat of fusion for water is 334 joules per gram. If we divide the total energy of the volcano by the heat off fusion of water, we will get the number of grams of ice that could be melted. Doing the math:
1.0E+17 joules / 334 joules per gram = 3.0E+14 grams
OK, the energy released by Mount St. Helens would melt about 3.0E+14 (three hundred million million) grams of ice. A gram of ice is about 1.1 cubic centimeters (1.1 cc), so we can round it to 1 cc just to make things simple. That means that Mount St Helens released enough energy to melt 3.0E+14 cubic centimeters of ice.
Let’s get a handle on what “3.0E+14 cubic centimeters of ice” means. A cubic meter of ice is the same as 1,000,000 cubic centimeters of ice. So, 3.0E+14 cubic centimeters of ice are the same as 3.0E+8 cubic meters of ice. Still a pretty big number to grasp. A sheet of ice that is one meter thick and one square kilometer would have a volume of 1 million cubic meters (1.0E+6 m3). In this case, 3.0E+8 cubic meters of ice would be the same as 300 square kilometers of ice that is 1 meter thick.
Now we have a number that is easier to deal with. That is, the energy of Mount St. Helens would be enough to melt 300 square kilometers or ice that is 1 meter thick. Finally, we’ll make the estimate that the ice is about 3 meters thick in the arctic. (Of course, it is much thicker some places and much thinner in others.) Then the energy of Mount St. Helens would melt about 100 square kilometers of ice in the Arctic.
The bottom line
The Arctic goes through some serious changes in sea ice extent every year as the season change. The sea ice extent changes by about 10 million square kilometers every year. 100 square kilometers is about one hundred thousandth of that. It would take a thousand volcanos the size of Mount St. Helens every year to account for just 1% of the yearly Arctic ice loss.
I am not only a global warming sceptic, but a skeptic in general. I call ‘em as I see ‘em.
Mount St Helens explosion, May 18th, 1980.
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I think it would translate to less than that in reality since the volcano is on the bottom of the Arctic sea and there is a considerable amount of water that would have to be heated before the ice would be affected.
Unless the volcanism is at or near the surface (as it is along the coast of the Antarctic) I would not think it would have much of an effect.
Bill Marsh,
Thanks for your comment. You are absolutely correct. I am assuming all the energy is transferred through the water, without heating it, etc., directly to the ice.
My point is that the upper limit of the amount of melted ice is vanishingly small.
Tom
ClimateSanity
My mathematical knowledge consistsa of the multiplication tables I learned in 1932
Given how much we don’t know about this volcanism which wasn’t discovered till long after it occurred, I’d say there is no real evidence to disprove any such contention at this point. Let’s hear more about this before making a slam dunk comment on such huge processes.
David Gladstone,
Like I said, I call them as I see them.
The numbers pretty much say it all. This one is, in fact, a slam dunk.
Tom
So, what about the effect of the warming over time? There are quite a few volcanos under the water in the Arctic and they have been heating the water up there for years.
I like seeing the calculation and it its very interesting reading. Thanks. I just had a couple of thought reading this though.
When I first read about the volcano eruption under the arctic ocean, I heard that up until this was discovered it had been thought impossible for an eruption at that depth because of the intense water pressure above it. So wouldn’t that mean that this eruption would be large compared to Mt. St. Helens? As also indicated by the fact that this would have “created explosive fountains rising up to 2 km in the water column.” I think your energy cacluation might be off by an order of magnitude low. Even still by your figures that would be only 1000 sq kilometers. Maybe I’m guessing too high?
“The volcanic events at Gakkel Ridge were not a one-off, the team says, and could be ongoing.” So an ongoing effect could change your calculation too. What do you think?
My quotes come from: http://environment.newscientist.com/article/dn14203-arctic-volcanoes-exploded-at-impossible-depth.html
But the ongoing effect would have been likely occurring for hundreds or thousands of years. As such, it would not change the energy balance of the region at all, as it would already be factored in, so to speak.
In other words, regular volcanic eruptions do not explain changes in temperature. There would have needed to have been a recent massive change in eruption patterns. How massive a change? The mathematics provided above tell us.
Lloyd,
Thank you for the comment.
You are correct that we do not really know the energy released by this volcano, and it could indeed be an order of magnitude greater than Mount Saint Helens. Maybe two orders or magnitude greater.
But even if it were two orders of magnitude greater, it would still take 10 such eruptions a year to melt just 1% of the ice that normally melts during the expected seasonal oscillation.
And the chances of this happening year in and year out – very remote.
Tom
David G., even if the volcanic activity was ongoing, it’s not at a steady state. From what I’ve read, ‘99 and ‘01 had very large seismic activity in that area indicating very large volcanic activity.
What about the fact the ice is in contact with salty sea water? How would that play into your calculations?
Thanks.
I read there were 12 volcanoes discovered plus who knows how many thousands of under sea vents “black smokers”in the Arctic,Also an estimated 3 million vents world wide which would have an effect on water finding it’s way into the Arctic Sea.I think there’s a real possibility you may have underestimated the effect.Also there are satalite pics that clearly show the melt above the Gekkal ridge area.Don’t forget when boiling hot water or steam is released from high pressures it creates super heated steam.
The fact there were unusual polar axis wobbles that would create plate boundary stresses in the same time frame of BOTH 1930’s high temps AND AROUND 2000 high temps that makes a higher rate of geothermal activity therefore higher Ocean temps much more believable.
Besides the earth-quakes that go along with plate movement would be the reason for ice shelves to break and speeding up of some glaciers rather than an effect of melting.The fact that the Ice had sharp cracks showed no rounded edges from melting proves the point even further.
Lewis,
The numbers I calculated for the amount of ice that could be melted by a Mt. St. Helens size volcano are an upper limit. That is, if all the released energy were transported to the ice, without any losses along the way. In reality, the considerable amount of water between the volcano on the bottom of the ocean and the ice on the top would also have to be heated, reducing the amount of energy to reach the ice.
Consequently, the actual melting would have to be less than what I calculated. Hence, itis an upper limit.
Best regards,
Tom
Barry Day,
You make some interesting points, but I am unconvinced. Here’s why:
The volume of the oceans is about 1.3 billion cubic kilometers (1.3E+9 km3). There are 1,000,000,000,000,000 cubic centimeters (1E+15 cm3) in a cubic kilometer. So, there are about 1.3E+24 cm3 of water in the ocean.
It takes about 4 Joules of energy to raise one cubic centimeter of water 1 degree C. So it would take about 5E+24 joules of energy to raise the oceans 1 degree C.
Recall from the post above that Mt. St. Helens released about 1.0E+17 joules of energy.
So it would take the energy of about 2E+7, or 20 million, Mt. St. Helens sized eruptions to raise the temperature of the oceans 1 degree C.
Keep in mind that I am talking in terms of energy, and my calculations represent an upper limit. There really doesn’t appear to be anyway to get around it.
Black smokers, for example, are tiny pinpricks compared to a full scale eruption like Mt. St. Helens. They are found along deep ocean ridges. It would take billions and billions of them to have much effect.
Best Regards,
Tom
“It takes about 4 Joules of energy to raise one cubic centimeter of water 1 degree C. So it would take about 5E+24 joules of energy to raise the oceans 1 degree C.”
Is that the surface top centimeter only?as heat rises and spreads.
At least the Volcanoes and vents should be mentioned as a posibillity as a reason when ice shelves with no evidence of melting(sharp corner edges) break away.
As for not having much effect!
Circles in Thin Ice, Lake Baikal, Russia
http://eol.jsc.nasa.gov/sseop/EFS/photoinfo.pl?PHOTO=ISS019-E-10556
Thanks for answering Tom,
This is where I’m having problems understanding how the Ocean does warm up at all if that were the caseas,The same rules would apply for the rather weak effect of the Sun in that region.Thats why I think the under-sea Volcanoes,vents etc,and what has not been mentioned yet;
(1)”Who knows how many Sq Klm’s of warm Sea floor crust area heat transfer”?
(2The interaction between Sun,Earth Magnetic Fields.
“The fact that the core-mantle interface is a super-conducting region…….The “hot spot” generates a thermal power of up to 10 13 watts and an equatorial current of about 10 9 amperes. The current is held to a narrow equatorial path by the well-known “pinch effect”. The total resistance of the equatorial circuit is no greater than 10 -10 ohms. The 10 9 ampere current creates the “polar” magnetic field. The secondary “non-polar” fields are induction effects due to minor fluctuations (ripples) in the equatorial current.
Paleomagnetic polarity reversals are initiated by turbulence, and by imbalances in kinetic pressure (nkT) and magnetic pressure (B 2 /2μ0). Westward drift is explained by the common direction of rotation and the differential angular velocities of the Earth’s core and the Moon. The heat generated by the model explains the persistent molten state of the Earths core over a long geologic time, the nature of the deeper part of the geothermal gradient, and the non radiogenic heat emitted by the Earth. This heat is sufficient to drive all thermally-driven geodynamic processes that are of deep origin.”
http://www3.interscience.wiley.com/journal/120020443/abstract?CRETRY=1&SRETRY=0
Especially after finding this paper by;
Climate Change is Nothing New – By Emeritus Professor Lance Endersbee, AO.
“”As I write this a research ship is heading to a part of the Mid-Atlantic Fracture Zone where there is a huge gaping hole in the oceanic floor where the normal ocean crust seems to be missing. The ocean crust is normally about 6km thick, but in this place it is virtually nil.
>>It is claimed that the area of the hole is thousands of square kilometres in extent.<<
Without pre-judging the results of the expedition, it
is reasonable to anticipate that this area could be found to be another new source of high geothermal heat flow into the Atlantic Ocean.”"
This is why I feel theres more that need to be taken into account and included in the maths equasion to make it believable.
The mountain range in question did not explode, it was built up much like the volcanos in the ocean that have been seen boiling the ocean surface. So the question then is if volcanos can boil the surface of the ocean then can they melt ice? Yeah I am pretty sure that is the case.
Jeff,
This post concerned this report of explosive volcanoes in the Gakkel Ridge. I am very interested (and skeptical) about any information you have concerning ocean bottom volcanoes “boiling the ocean surface.” Can you provide a link.
Best Regards,
Tom
I just remembered something else. In Antarctica, there is an underwater “dormant” volcano by Deception Island. The water in the caldera is apparently hot enough to scald you if you’re not careful, but people actually take a dip in the hot springs there. Check out this video:
“When Antarctica Was Green” http://www.geolsoc.org.uk/gsl/site/GSL/lang/en/page3155.html
(scroll down the page for the link to view)
You are ONLY using the thermal energy released during the erruption on ONE day 18May80. Also not factoring in the mechanical energy that ejected 0.67 cubic miles of material or the Lahars totaling 3,900,000 cubic yards of melted ice/snow and soil/rocks. Of that ONE day, that your were using to justify your ASSUMPTION.
The multible underwater volcanoes along the Gakkel Ridge have been active for 10+years. NOT just ONE day……..
Also you forgot to factor the Latent heat requirement to change the physical state of the ice into water. 144BTU of heat is required to change 5 pounds of ice to water or 3.34 x 105J/kg at 32 degrees.
Dear AC Robertson,
I am not “ONLY using the thermal energy.” of the Mt. St. Helens eruption in my calculation. I am using a common estimate for the TOTAL energy release by the Mt. St. Helens eruption. This includes the mechanical and thermal energy.
The daily activity in the Gakkel Ridge area is nothing compared to a full scale explosion. But what if the energy released in the Gekkel Ridge every single day for the last 10 years were equal to the energy of Mt. St. Helens on May 18th, 1980? That would still only be enough to melt 3.5% of the Arctic ice (assuming an average of 3 meters thick spread over 10 million square kilometers.
The number make is quite plain. This is not causing increased Arctic melting.
Best Regards,
Tom