[Paper] Interventions that May Prevent or Mollify Supervolcanic Eruptions

by Denkenberger15th Jan 20188 comments

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SupervolcanoExistential risk
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Supervolcanic eruptions are approximately 10 times as powerful as the eruption that caused the year without a summer in 1816. A supervolcanic eruption would cause local devastation, but the main problem is blocking the sun for years and starvation (with possible loss of civilization without recovery and other far future effects). Indeed, many people think that the genetic bottleneck of humans going to a population of only a few thousand was due to a super volcanic eruption 74,000 years ago. It is widely assumed that there is nothing we can do to prevent or mollify supervolcanic eruptions. However, I came up with over 50 possible interventions. In the paper, we could not get into economics. I have done some initial estimates that indicate that the most promising interventions of adding soil or water on top of the supervolcano to delay an eruption for 100 years would likely be cost-effective only considering the present generation. However, this is in isolation. In reality, the first thing we should do is get prepared with alternate foods that are not dependent on sunlight. This would protect against the majority of the damage associated with a supervolcanic eruption, making prevention of a supervolcanic eruption less cost-effective. Still, since people are already doing research on supervolcanic eruptions, it may make sense to nudge that research towards directions that would reduce global catastrophic/extistential risk.

Here is the full paper and below is the abstract:

A supervolcanic eruption of 10^15 kg could block the sun for years, causing mass starvation or even extinction of some species, including humans. Despite awareness of this problem for several decades, only five interventions have been proposed. In this paper, we increase the number of total possible interventions by more than an order of magnitude. The 64 total interventions involve changing magma characteristics, venting magma, strengthening the cap (rock above the magma), putting more pressure on the magma, stopping an eruption in progress, containing the erupted material, disrupting the plume, or provoking a less intense eruption. We  provide qualitative evaluations of the feasibility and risk of 38 of the more promising interventions. The two most promising interventions involve putting more pressure on the magma and delaying the eruption with water dams or soil over the magma chamber. We perform a technical analysis, accurate to within an order of magnitude, and find that water dams and soil and could statistically delay the eruption for a century with 1 and 15 years of effort, respectively. All actions require essentially untested geoengineering challenges along with economic, political and general public acceptance. Further work is required to refine the science, provide cost estimates, and compare cost effectiveness with interventions focusing on adapting to a supereruption.

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Thanks for this interesting paper. Having looked into this a bit, my impression is that some of the figures on the risk posed by supervolcanoes are too high.

Estimates of the frequency of VEI=8 eruptions vary from 30,000 years to around 130,000 years ( W. Aspinall et al., “Volcano Hazard and Exposure in GFDRR Priority Countries and Risk Mitigation Measures,” Volcano Risk Study 0100806- 00-1-R, 2011, 15; Susan Loughlin et al., Global Volcanic Hazards and Risk (Cambridge University Press, 2015), 97)

If VEI=8 events are as frequent as suggested in your paper (on the order of 10,000 years), it seems extremely unlikely that they would constitute an ex risk: the homo genus would have had to have gone through this 120 times and survived at much lower levels of technical sophistication than today.

Some of the literature estimates the frequency of VEI=9 events at one every 30 million years, with massive uncertainty. (Aspinall et al., “Volcano Hazard and Exposure in GFDRR Priority Countries and Risk Mitigation Measures,” 15.)

Thanks for the feedback. I cited the most recent study that claims to have identified more eruptions than previous studies: Rougier, J., Sparks, R. S. J., Cashman, K. V., & Brown, S. K. (2018). The global magnitude–frequency relationship for large explosive volcanic eruptions. Earth and Planetary Science Letters, 482, 621–629. However, perhaps I should not update so strongly because you are right that other estimates are closer to the order of 100,000 years. That is good to think about what it means in terms of existential risk historically. Survivorship bias should not change things too much. Our circumstance is significantly different now. On the plus side, we have more population, more food storage and better knowledge of what is happening. But on the minus side, a super volcanic eruption could raise tensions such that nuclear war breaks out, which would be even worse.

This is fantastic! Thank you for writing this. I think that far too often people see a problem then say, "it's not tractable because I can't think of anything you can do about it" before they've even given it 10 minutes thought. And often causes require far more than 10 minutes thought to come up with some good potential solutions!

That was a really interesting paper!

Has there been any follow up work by you or others to refine your risk estimates, in particular to estimate the change to hazard rate?  

So for example, you consider covering Yellowstone with 25 cm of unconsolidated material as a way to delay the next eruption and give us time to develop technology for a more permanent solution over the next, say, 50 or 100 years.   You estimate that intervention increases the expected value (EV) of the time to the next eruption by 100 years.  So that's great, but I think what we really care about is something more like the hazard rate over the near term: what is the probability of preventing an eruption over next 50 or 100 years ?  If the rate at which the pressure in the magma chamber increases is roughly constant, this distinction doesn't really matter and a 100 year increase in EV means an eruption in the next 50 years is much less likely.  But if it's very far from uniform, the 100 year increase in EV might not be as great as it sounds.  So e.g. say the process is driven by large jumps in pressure on a timescale of every 1000 years or so, then increasing the EV by 100 years is only decreasing the hazard rate by 10%: an eruption in the near term is still 90% as likely after the intervention as before. 

Another consideration is are the dynamics any different between intervening at a random time vs. intervening when there are signs an eruption may be soon (but still enough time to complete the intervention)?

Thanks! Those are good questions. I have not put any more effort into it because resilient foods are likely lower cost to prepare for and protect against multiple catastrophes including super-volcanic eruptions. However, if we can get a few hundred million dollars for resilient foods, maybe working on preventing super-volcanic eruptions will be next on the list…

Your food resilience work is great: fascinating and really important!  Indeed, I first heard of your supervolcano paper via your interview with Rob Wiblin which was primarily about feeding humanity after a catastrophe.  In the grand scheme of things, that's rightly higher priority, but the supervolcano stuff also caught my interest.

I happen to know a couple of volcanologists, so I asked them about your paper.  They weren't familiar with it, but  independently stressed that something quite tractable that  would  benefit from more resources is better monitoring of volcanoes and prediction of eruptions.  

The typical application of forecasting eruptions is evacuation.  But that's sociologically tricky when you inevitably have probabilities far from 1 and uncertain timelines, since an evacuation that ends up appearing unnecessary will lead to low compliance later (the volcanologists "cried wolf").  With interventions to prevent an eruption, that's much less of an issue.  Say you had a forecast  that a certain supervolcano  has a probability of 20% of erupting in the next century, so many orders of magnitude  above base rate.  That's still realistically pretty useless from the point of view of evacuation, but would make your kind of interventions very attractive (if they work in that case).   

So if  it could shown that these interventions are likely tractable even when a potential near term eruption has been detected, then that would justify increased investment both in detection/forecasting and developing these approaches.

Nice. But you don't take reliability and breakdown concerns in your calculation regarding dump trucks. Especially if they are being run 24/7 in night and bad weather conditions, allow for a nontrivial fraction of them to be broken down and under repair at any given time. This could be an enormous problem for the first few years of action because repair and maintenance services don't exist in such a high concentration to handle so many heavy vehicles in a remote location.

Also, see how many such vehicles are owned by the US National Guard, Seabees, etc. They may not be listed in the FHA's statistics.

Thanks for your careful read. I suggested 160 hours per week operating, which allows for 8 hours a week for fueling, scheduled maintenance, and unscheduled maintenance. This is probably optimistic, but I think my estimates are low by an order of magnitude compared to what we could do with non-dumptrucks (though these would likely require retrofitting).