New threat from Climate change and the use of Geo-engineering

[david....@carbon-cycle.co.uk]

I believe that I have identified a new feedback loop/threat that emerges from the current trends of climate change. This new threat is likely to eclipse the already identified impacts of climate change and changes the moral calculation about whether to use geoengineering to cool the planet. It becomes immoral to fail to use geo-engineering to prevent this dangerous feedback loop from occurring.

We are in the process of increasing vulcanism of approximately 100 volcanoes and a super volcano as large as Yellowstone in the Southwestern Antarctica.  The eruption of a large super volcano will potentially release greater than 10,000 cubic kilometres of lava and ash (for perspective, Mt St Helen’s eruption was about 1 cubic kilometre). To make matters worse, the glaciers of this region are inherently unstable because they are grounded below sea level – meaning they can rapidly collapse. Approximately half the flow of ice to the sea from the ice sheet above Marie Byrd land is estimated to be the result of the melt water created by the heat of the super volcano below the ice. The Marie Byrd Land ice sheet is largely held back by the Thwaites ice sheet which is sometimes call the disaster glacier because it is considered to be unstable and could collapse relatively rapidly and raise world sea levels by 0.6 metres.

The Thwaites and Marie Byrd Land Ice sheets are up to three kilometres thick. They have lost between 60 to 100 metres of ice thickness as a result of climate change already.  Data from the melting of Iceland’s glaciers indicates that roughly speaking, the land rises approximately 1 metre for every 1 metre of ice that is melted over time. Therefore, when the weight of the ice sheet is removed from the underlying super volcano, the land could rise by kilometres over time. It would be a reasonable expectation that such a large land movement risk awaking the super volcano and the large number of volcanoes beneath Southwestern Antarctica.

The feedback loop of concern is as follows:

1. The weight of the ice sheet above the super volcano and 100 other volcanoes reduces. This causes the land below to rise and increases the volcanic activity.
2. The increased volcanic activity increases the release of heat from the super volcano and other volcanoes which then increases the volume of meltwater below the ice sheet.
3. Increased melt water lubricates the flow of the ice sheets resulting in increased flow of ice out of the ice sheets leading to further loss of mass from the ice sheet which then further increases volcanic heat flux.
4. This occurs until the ice sheets in Marie Byrd land and Southwestern Antarctica transition to rapid collapse from the below sea level portion of the ice sheet. Melting these ice sheets will raise sea levels and threaten coastal cities across the world.
5. Collapse of the ice sheet removes the kilometres of ice weight from on top of the super volcano and the other volcanoes. Potentially the land will rise kilometres to seek equilibrium from the loss of the ice weight. Vulcanism increases significantly as a result.
6. The rising of the land fully awakens the super volcano, and a long period of potentially very disruptive volcanism results.

It is worth noting that there has not been a large super volcano eruption since before our species evolved into being and could potentially be a significant threat to our civilization/survival. The rapid collapse of the ice sheets outlined would flood most of the world’s major cities. If it occurred within a short period of time such as a few decades, it would have severe economic and social disruption. A super volcano reawaken by the loss ice kilometres thick would likely be active for an extended period of time while the land was out of pressure equilibrium. From a human perspective of time, the awakening of a super volcano risks creating near permanent changes to the Earth’s climate. A super volcanic eruption could not be stopped once started.

I am unaware of any climate models that take the described feedback loop into account. I fear the impacts described will result in very different outcomes from the current models.

The use of geo-engineering to prevent what I have outlined from occurring is moral. To not act to prevent this is immoral. Once the feedback loop passes a certain tipping point, it will be impossible to stop. The risk of this occurring eclipses the risk that there will be a delay in ending the burning of fossil fuels. Geo-engineering should NOT wait until the end of the decade to undertake trials. To do so risks passing dangerous tipping points. It should be used at scale as soon as practicable and prevent this deeply worrying feedback loop from happening. I strongly believe that when presented with this new threat and the use of geo-engineering to try to prevent this threat from occurring, the public will strongly back the use of geo-engineering. I also believe that it will focus the minds of politicians to finally act to cut carbon emissions.

 

David Sevier

[Stuart Haszeldine]

Hello David, I can certainly relate to your line of arguement. I guess that the hazard depends on the unloading by ice melt being sufficient in pressure change to trigger eruptions - initially from magma at critical balance near-surface.  

Heres two thoughts, and then a piece of information.

1) your reasoning will apply to any past rapid warming, to unload ice sheets. Haas anybody looked for changes in volcanism frequency or size during past glacial cycles, or coming out of glacial periods into warmer millennia.

2) If a super-volcano erupts, then its probably goodbye - but humans and most species did survive Mt Taupo about 22kyr ago.  I think magma reservoirs need about 50% liquid for a large scale eruption - so if there has been geophysics across the Antarctic that may be able to inform us if its ready to trigger or not.

3)  As additional information, the Quaternary record of tephra from Iceland has been investigated during the ast couple of decades to test a similar theory that unroofing ice load from volcanoes with shallow depth magma can trigger eruptions.  2km ice melt is 20 MPascal pressure change - so a big change on magma at 2km (50 MPa).   Less significant at 8km depth of magma chamber for Yellowstone or Taupo super volcanoes where the pressure is 200MPa, though a 10% change within hundreds of years ice melting is still a good trigger. 

This is C.L. Cooper and G.T Swindles Quaternary Sciences Advances  

May 2020.  https://doi.org/10.1016/j.qsa.2020.100004   And the correlation (attached) does appear to have some linkage by eye - though I’m sure that time series analysts in this group can do a better statistical job than that.

Stuart

Stuart Haszeldine  OBE FRSE C.Geol

Professor of Carbon Capture and Storage

School of GeoSciences
University of Edinburgh
Scotland UK, EH9 3FE

On 16 Aug 2021, at 17:35, <david....@carbon-cycle.co.uk> <david....@carbon-cycle.co.uk> wrote:

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[david....@carbon-cycle.co.uk]

Stuart,

 

I read the paper that you kindly sent as a reference. I can see some issues that are relevant to compare Iceland ice loss to loss of ice in Marie Byrd land above the super volcano:

 

1. The ice sheet thickness in Iceland is an average of 400 metres and a maximum thickness. The Western Antarctica  ice sheet above the super volcano is 5 or 6 times this thickness. The response could be greater as a result?
2. The super volcano currently is active as it provides heat that is responsible for half the ice flow from this glacier. I am unsure exactly how to line up this level of activity with potential magma levels that would mean that it is “primed” for eruption if the ice is removed.
3. The last time that Western Antarctica was ice free was 35 million years ago. I don’t know where we could look to for a similar situation where this thickness of ice is removed from on top of a super volcano. While I am sure this has happened before, I am unaware of this happening in the near geological time period which will likely mean that getting detailed predictions of what might happen over dozens/centuries of time from what has previously occurred may not be possible.

 

A significant concern is that we are placing a lot of hopes for the future on the current climate models. If what I fear does happen, then we are going to enter completely unknown and potentially quite dangerous territory. If there is delay in the volcanic activity uptick after the loss of ice we may also only discover the folly of what has occurred when it is far too late.

 

Undertaking an experiment of this danger is very foolish. At the very least we should investigate this further, quantify the danger, and revisit our climate models and explore the impact of this occurring. Flying blind into a future without understanding this is madness.

 

 

David Sevier

 

Carbon Cycle Limited

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Tel 44 (0) 208 288 0128

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[SALTER Stephen]

David

 

I sent a copy of your previous email of 16 August to people a DBEIS asking them to confirm receipt.

 

Nothing back yet.

 

Stephen

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[Andrew Lockley]

https://www.newscientist.com/article/dn13583-melting-ice-caps-may-trigger-more-volcanic-eruptions/

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Melting ice caps may trigger more volcanic eruptions

EARTH 3 April 2008

By Catherine Brahic

New Scientist Default Image

Vatnajökull in the south-east is the largest ice cap in Iceland and conceals several volcanoes

(Image: NASA)

A warmer world could be a more explosive one. Global warming is having a much more profound effect than just melting ice caps – it is melting magma too.

Vatnajökull is the largest ice cap in Iceland, and is disappearing at a rate of 5 cubic kilometres per year.

Carolina Pagli of the University of Leeds, UK, and Freysteinn Sigmundsson of the University of Iceland have calculated the effects of the melting on the crust and magma underneath.

They say that, as the ice disappears, it relieves the pressure exerted on the rocks deep under the ice sheet, increasing the rate at which it melts into magma. An average of 1.4 cubic kilometres has been produced every century since 1890, a 10% increase on the background rate.

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Frequent eruptions

In Iceland there are several active volcanoes under the ice. The last big eruption was in 1996 at Gjàlp, and before then in 1938 – a gap of 58 years. But Pagli and Sigmundsson say that the extra magma produced as the ice cap melts could supply enough magma for similar eruptions to take place every 30 years on average.

Predicting the eruptions precisely will be tricky, though, as the rate of magma migration to the surface is unknown.

The situation in Iceland does not necessarily mean magma will be melting faster around the world. Vatnajökull sits atop a boundary between plates in the Earth’s crust, and it is this configuration that is allowing the release in pressure to have such a great effect deep in the mantle.

But the thinning ice has another effect on volcanoes which will be more widespread.

As the amount of weight on the crust changes, geological stresses inside the crust will also change, increasing the likelihood of eruptions. “Under the ice’s weight, the crust bends and as you melt the ice the crust will bounce up again,” explains Bill McGuire of University College London in the UK, who was not involved in the study.

Unexpected activity

Pagli say places likely to be at increased risk of eruption due to ice-melt include Antarctica’s Mount Erebus, the Aleutian Islands and other Alaskan volcanoes.

The shifting stress might even cause eruptions in unexpected places.

“We think that during the Gjàlp eruption, magma reached the surface at an unusual location, mid-way between two volcanoes, because of these stress changes,” says Pagli.

McGuire thinks the Vatnajökull study is based on “perfectly reasonable” physics. However, he says that climate change presents an even more explosive threat. “It’s not just unloading the crust that triggers volcanic activity but loading as well.”

He and his team are looking into the effects that rising sea-levels – also a consequence of melting ice caps – will have on volcanoes. “We are going to see a massive increase in volcanic activity globally,” he told New Scientist. “If we look back at previous warm periods, that is what happened.”

Journal reference: Geophysical Research Letters (in press)

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[Renaud de RICHTER]

https://phys.org/news/2021-08-thwaites-glacier-significant-geothermal-beneath.html 

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[david....@carbon-cycle.co.uk]

Renauld’s reference is very relevant to this discussion. It is worth looking at the actual published material at http://dx.doi.org/10.1038/s43247-021-00242-3   The communication shows that there is a high heat flux below this region’s glaciers and in particular the Thwaites and Popes Glaciers which act as a cork for much of the Marie Byrd Ice sheet which covers the super volcano.  This is not good news as the data indicates that this region is particularly susceptible to effects of loss of ice mass due to the thin earth crust below the glaciers.

 

Basically the feedback loop that I have laid out is supported by this data and could come to pass. Does anyone know if any of the climate modelling includes any of this? Are we flying blind into a possible situation where all our models and predictions are wildly off? At the very least there needs to be some modelling of this and estimates of risk of it happening so some sensible decision making can be made. Ultimately if it is agreed that the risks are what I have outlined, there needs to be public discussion around this and what can be done to prevent this (emission cuts and geo-engineering if we are at or close to a dangerous tipping point (which I fear may already the case)).

 

Dave

 

On 16 Aug 2021, at 17:35, <david....@carbon-cycle.co.uk> <david....@carbon-cycle.co.uk> wrote: