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Discussion > GHG Theory step by step

By accident, I heard a few minutes of the Radio 4 "Desert Island Discs" this morning. Jane Francis was being interviewed. She mentioned that the Antarctic climate had changed in recent years.

I didn't hear any details but I had trouble reconciling what she said with the message that I have been getting from all sources which is that for at least the last couple of decades, the Antarctic has had record low temperatures and record ice extents.

The exception has been the Antarctic Peninsula which has for years been a bone of contention in climate debate because it appears to be a hot spot. Very recently, I heard that the peninsula contains a range of semi-active volcanoes under the ice, which would fully explain the hot spot behaviour.

I don't know whether or not this explains what Jane Francis was talking about. Can anyone shed light on all of this?

Sep 29, 2017 at 7:38 PM | Unregistered CommenterSchrodinger's Cat

Schrodinger's Cat
I am intrigued by volcanic activity influencing the climate, and particularly land and sea ice extent, whether short or medium to longer term.

The Antarctic peninsular has attracted controversy:

The negative correlation between Arctic and Antarctic ice extent was noted by the IPCC as mentioned in this recent thread:

Sep 29, 2017 at 8:16 PM | Unregistered Commentergolf charlie

Scientists discover 91 volcanoes under the ice in Antarctica as reported by the Guardian, a newspaper not noted for its honesty about global warming.

Sep 29, 2017 at 9:15 PM | Unregistered CommenterSchrodinger's Cat

SC, ah yes, but ...

""However, he pointed to one alarming trend: “The most volcanism that is going in the world at present is in regions that have only recently lost their glacier covering – after the end of the last ice age. These places include Iceland and Alaska.

“Theory suggests that this is occurring because, without ice sheets on top of them, there is a release of pressure on the regions’ volcanoes and they become more active.”

And this could happen in west Antarctica, where significant warming in the region caused by climate change has begun to affect its ice sheets. If they are reduced significantly, this could release pressure on the volcanoes that lie below and lead to eruptions that could further destabilise the ice sheets and enhance sea level rises that are already affecting our oceans.

“It is something we will have to watch closely,” Bingham said.""

So it could be that the manmade CO2, that causes Global Warming, causes volcanic eruptions! (add it to the very long list)

Sep 29, 2017 at 10:06 PM | Unregistered Commentergolf charlie

Golf Charlie

If you want certainty, find a politician or a priest.

Science is never certain.

A lot depends on the details of the eruption. A large eruption will produce short term cooling from the aerosols and long term warming from the CO2.

Sep 29, 2017 at 11:25 PM | Unregistered CommenterEntropic man

A large eruption will produce short term cooling from the aerosols and long term warming from the CO2.
Are you sure about that?

Anyway, I thought that the science was settled – there can be no more doubt about the certainty of AGW.

Sep 29, 2017 at 11:54 PM | Registered CommenterRadical Rodent

Schrodinger's cat

If you do the numbers, I think you will find that the volcanoes do not produce enough energy to explain the observed warming in the Antarctic Peninsula.

The supposed link between ice capss and volcanoes is that the pressure of the ice mass keeps gases in magma chambers dissolved.

When the ice melts, the pressure it exerts on the magma chamber decreases and some of the dissolved gas comes out of solution.

The magma chamber can go two ways.

It can stabilise at a new equilibrium pressure as released gas increases the pressure in the chamber and stops further gas release.

The pressure due to gas release gets high enough to force material to the surface and you have an eruption.

Sep 29, 2017 at 11:59 PM | Unregistered CommenterEntropic man

Radical rodent

No certainty, but a high probability in both cases.

Sep 30, 2017 at 12:02 AM | Unregistered CommenterEntropic man

EM. Most of the volcanos have been recently discovered, yet you can confidently conclude that they would provide insufficient heat. Sheech!

Sep 30, 2017 at 7:32 AM | Unregistered CommenterSupertroll


Do the numbers.

I remember similar denier enthusiasm when volcanic activity was discovered under the Thwaites glacier. There were wild claims that all the melting from the glacier was due to volcanoes. In fact, even the most optimistic heat flow calculation showed that it was less than 1%.

An old geologist like you should know better than to jump to absurd conclusions without data.

Sep 30, 2017 at 8:14 AM | Unregistered CommenterEntropic man

you should know better than to jump to absurd conclusions without data.

Sep 30, 2017 at 8:14 AM | Entropic man

Can you provide the data used to conclude that CO2 is the Earth's Temperature control knob, and how it caused the MWP and LIA?

Sep 30, 2017 at 10:36 AM | Unregistered Commentergolf charlie

EM, do you have any comment about the assumptions accepted by the consensus, that may explain why the models are overheating?

Step 4: Radiative forcing is a useful diagnostic and can easily be calculated
Step 5: Climate sensitivity is around 3ºC for a doubling of CO2
Step 6: Radiative forcing x climate sensitivity is a significant number

Curry and Lewis dispute the 3C figure for ECS. What happens to the models if ECS is actually less than 1?

Sep 30, 2017 at 10:48 AM | Unregistered Commentergolf charlie

EM. Its not the volcanos that are important (they are just symptoms) its the size of the magma chambers and their depth (probably both as yet poorly known). It's like the fallacy of melting permafrost. It doesn't melt from above but from below when surface warming reduces the rate at which subsurface heat is lost. Soils are extremely poor heat conductors.

I am perfectly willing to believe that geothermal heat plays a role, but it's more likely the northward extension of the peninsula into the circumpolar winds and currents that plays the major role. Magma chambers may also be responsible for slightly warmer conditions and enhanced melting in eastern Greenland.

BTW less with the insults. I do not criticize your genuine attempts to reach the truth.

Sep 30, 2017 at 11:57 AM | Unregistered CommenterSupertroll

EM can you explain, for the benefit of "an old geologist like [me who]should know better than to jump to absurd conclusions without data" exactly how the BASE of the Twaites Glacier, away from the coast (where it is not warmed by the ocean) is melting? The geophysical work done by the University of Texas at Austin would appear to be the data necessary to reach a conclusion.
Perhaps you could point me to a study that shows basal ice melting by geothermal heat is not feasible. To date I only know of statements made by "experts" from other universities who, as far as I can tell, have no data of their own and are just expressing opinions. Always willing to be proven wrong, however.

Sep 30, 2017 at 1:00 PM | Unregistered CommenterSupertroll

Sep 30, 2017 at 1:00 PM | Supertroll

Is the Antarctic Peninsula an extension of the Pacific "Rim of Fire" that runs down the Eastern perimeter of the Pacific, that is known for earthquakes and volcanic activity, past and present?

Sep 30, 2017 at 1:53 PM | Unregistered Commentergolf charlie

GolfCharlie. The simple answer is that I don't know. Mountains along the Peninsula are often considered as an extension of the Andes which would suggest there is a subduction zone along its western coast (and therefore it's part of the Ring of Fire) but I can't find mention of it. There are many features about Antarctic geology that seem fuzzy. Some maps show a single tectonic plate, whereas elsewhere a subduction zone is shown along the west side of the TransAntarctic Mountains implying separate East and West Antarctic Plates, not to mention a major zone of rifting in the same general area, comparable to that of East Africa. Volcanicity could therefore result from interplate hotspots, rift valley stretching or subduction. You pays yeh money and yeh takes your choice.
I have never been there.

Sep 30, 2017 at 3:46 PM | Unregistered CommenterSupertroll

Supertroll, thank you for clarifying/confirming the extent of "known unknowns"!

The article Schrodinger's Cat linked to:
seems relevent, and is what prompted me to try and google (without a conclusion) for an answer.

EM had referenced the mid Atlantic Ridge and involvement in PETM, and presumably the Ridge continues North of Iceland beneath Arctic Ice. It just seems that there are rather more missing pieces to the completed Climate Science jig saw, but other pieces have been artificially expanded to fill the gaps.

Sep 30, 2017 at 4:59 PM | Unregistered Commentergolf charlie

Antarctica is certainly not warming and has had record low temperatures and ice extents. As I mentioned above, the peninsula has always been at the centre of arguments. I think I am right in saying that there are few measurements in that area. For all I know, the weather station could be located on top of a volcano.

I'm not too bothered about the peninsula for these reasons.I was really questioning what Jane Francis was talking about when she claimed that the Antarctic climate had changed - unless she meant it had got colder. I doubt if that was the case because the BBC would have edited that out.

Sep 30, 2017 at 9:13 PM | Unregistered CommenterSchrodinger's Cat

Sep 30, 2017 at 8:14 AM | Unregistered CommenterEntropic man .

>Do the numbers.<

Be like.....Tesco?

Oct 1, 2017 at 9:43 AM | Unregistered Commenterhusq

Schrodinger's Cat

"Francis's principal interests are in palaeoclimatology and palaeobotany. She specialises in the study of fossil plants, and their use as tools for climate interpretation and information about past biodiversity:[12][13] for example, understanding past climate change during greenhouse and icehouse periods.[14] Her research has emphasised the "Antarctic paradox," that although the Antarctic is largely inhospitable now, its abundant plant fossils indicate a drastically warmer past climate.[15] She has undertaken more than 16 expeditions to the Arctic and Antarctic.[16]"

Perhaps she is trying to work out what else can cause global warming and cooling, in the absence of manmade CO2.

Oct 1, 2017 at 10:51 AM | Unregistered Commentergolf charlie

No certainty, but a high probability in both cases.
In fact, with so much confidence, there are calls for any questioning of it to be criminalised – to the point of capital punishment! This sort of philosophy has been applied before, usually by people who cannot accept that they might be wrong; the results have never been very pleasant. Can you not see the similarity, EM?

Oct 1, 2017 at 11:17 AM | Registered CommenterRadical Rodent

Oct 1, 2017 at 9:43 AM | husq

We should not forget ENRON, when it comes to corporate fraud, managing to fool Governments and Accountants, despite the warnings.

"At the beginning of 2001, the Enron Corporation, the world's dominant energy trader, appeared unstoppable. The company's decade-long effort to persuade lawmakers to deregulate electricity markets had succeeded from California to New York. Its ties to the Bush administration assured that its views would be heard in Washington. Its sales, profits and stock were soaring."

Oct 1, 2017 at 11:35 AM | Unregistered Commentergolf charlie

This sort of philosophy has been applied before, usually by people who cannot accept that they might be wrong; the results have never been very pleasant. Can you not see the similarity, EM?

Oct 1, 2017 at 11:17 AM | Radical Rodent

North Koreans do not even know that this philosophy is still in operation, as they are kept in the dark.

Oct 1, 2017 at 12:01 PM | Unregistered Commentergolf charlie

I recommend a post over at WUWT by Mikhail Voloshin.

He has no axe to grind about the climate but he discusses the difficulties in deciding whether a data trend is up, down, or just random. It is very well written, quite entertaining and he concludes that GISTEMP could up or random.

I don't think he has much admiration for climate data analysis.

Oct 1, 2017 at 6:42 PM | Unregistered CommenterSchrodinger's Cat

Golf Charlie

If ECS is less than 1 the negative feedbacks are more powerful than the positive feedbacks. The net temperature change is smaller than that caused by the forcing without feedbacks.

For example, consider a change in forcing due to solar insolation , which would produce a direct change of 1C without feedbacks. If the ECS was 0.5 then the change would be 0.5C when all feedbacks were included.

ECS applies to all forcings, not just CO2. The problem with small ECS values is that if you discount the effect of CO2 then all the other forcings are too small to explain the observed warming.

For example, if you wish to explain the observed warming using increased solar insolation, you need an ECS above 6 since the change in insolation is far too small to produce the observed warming on its own.

Oct 2, 2017 at 12:13 AM | Unregistered CommenterEntropic man