I think in a simplistic world- one in which we react to such threats as you expect with resilience and preparedness, then yes the risk of Tambora sized eruption could be minimal* (*by this I mean raising food and energy prices and dramatically impacting/causing excess mortality of poorer/vulnerable nations).
Yes the world is more resilient and famines are better etc (note that a VEI 5 eruption in 1982 led to the droughts and thus famine in Ethiopia in 1983-5 that led to half a million dying), but a more complex world has inherent weaknesses and new vulnerabilities, see here and here
I appreciate an increasingly complex world can have inherent weaknesses and new vulnerabilities (e.g. Bailey 2017 analyses the effects of interruptions at chokepoints in global food trade). However, we have to consider these effects together with ones pushing towards greater resilience to catastrophes, such as the benefits of having a world which can dedicate a greater fraction of its resources to food (including greater capacity for international assistance of low income countries). I assume one way of assessing the net effect is looking into how the death rate from protein-energy malnutrition has evolved over time. According to data from the Global Burden of Disease (GBD) study, it decreased 77.8 % (= 1 − 2.74/12.27) from 1990 to 2019 (see below). So I would say the world has become more resilient against small food shocks.
Large shocks happen less often, so the trend above is less informative, but a priori I would expect resilience to small shocks to be correlated with resilience to large shocks.
a VEI 5 eruption in 1982 led to the droughts and thus famine in Ethiopia in 1983-5 that led to half a million dying
I do not think this is a fair characterization of the risk linked to VEI 5 eruptions:
The 1983–1985 famine in Ethiopia was caused by “drought, the Ethiopian Civil War and military policies taken by the Ethiopian government”. Even if the drought was totally caused by a volcanic eruption of VEI 5 (wikipedia’s page does not mention any volcanic eruption; could you link to an article?), such eruption would not be responsible for all of the famine deaths.
Some of the famine deaths would have to be attributed to the other causes, such that the deaths attributed to each cause added up to the total death toll.
VEI 5 eruptions happen once every decade or so. As a result, a naive interpretation of your statement (I am not saying you would endorse it!) would say VEI 5 eruptions cause in expectation a famine with 0.5 M deaths every decade or so. However, the expected death toll would be much lower if the other causes (Ethiopian Civil War and military policies taken by the Ethiopian government) have a much lower probability.
This is why I mentioned in my last comment that:
The more factors are needed to cause extinction, the less likely it will tend to be, because it is then more conjunctive (even if many of the factors are correlated; one should be mindful of the conjunction fallacy).
Similarly, the more factors are needed to cause large famines (e.g. not only a VEI 5 eruption, but also civil war, and lack of effective international assistance), the less likely they will tend to be. This effect exists unless there is a perfect correlation between all the contributing causes (e.g. if a VEI 5 eruption always caused a civil war, and lack of effective international assistance).
Perhaps this is my scientific background, but how you put a number on such uncertain factors seems deeply unscientific/unrigourous to me.
I agree my analysis is far from rigorous. However:
It is hopefully better to have a non-rigorous analysis plus your thorough comment than the alternative of no analysis.
To illustrate, I could say the nearterm annual risk of human extinction from supervolcanoes is low, but then some readers may infer from this anything ranging from 0 to maybe 0.01 %. The latter would arguably imply volcanic risk receiving way more attention from the effective alstruism community than it currently does, whereas my actual best guess of 3.38*10^-14 does not.
So I think I had better provide my best guess for the risk. At the very least, this facilitates agreement/disagreement. If I had just mentioned the extinction risk was extremely low, you may not have provided such detailed and valuable feedback due to perceived agreement.
I also think researchers quite often implicitly put numbers on metrics. For example, you said:
Irrespective of extinction risk—should we care (and do something) about that fact that large volcanic eruptions could threaten the lives and livelihoods of billions, and this is for a risk that has a 1 in 6 per century probability?
Perhaps I’m in an alternative/more isolated worldview- but I would say yes.
It seems to me that, by answering yes to your question, you are implicitly arguing that there are interventions to decrease the expected mortality of volcanic eruptions whose cost to save a life is sufficiently low for such interventions to receive more attention (e.g. more research like yours on volcanic risk). Moreover, if by “we” you mean not just the world as a whole, but funders aligned with effective alstruism too (namely, Open Philanthropy), you may be implicitly claiming that such interventions can have a cost to save a life lower than 5 k$ (that of GiveWell’s top charities). I think it would be great if someone (maybe you and Lara!) published in a peer-reviewed journal a standard cost-effectiveness analysis of the interventions you think are being overlooked.
Thanks for following up, Michael!
I appreciate an increasingly complex world can have inherent weaknesses and new vulnerabilities (e.g. Bailey 2017 analyses the effects of interruptions at chokepoints in global food trade). However, we have to consider these effects together with ones pushing towards greater resilience to catastrophes, such as the benefits of having a world which can dedicate a greater fraction of its resources to food (including greater capacity for international assistance of low income countries). I assume one way of assessing the net effect is looking into how the death rate from protein-energy malnutrition has evolved over time. According to data from the Global Burden of Disease (GBD) study, it decreased 77.8 % (= 1 − 2.74/12.27) from 1990 to 2019 (see below). So I would say the world has become more resilient against small food shocks.
Large shocks happen less often, so the trend above is less informative, but a priori I would expect resilience to small shocks to be correlated with resilience to large shocks.
I do not think this is a fair characterization of the risk linked to VEI 5 eruptions:
The 1983–1985 famine in Ethiopia was caused by “drought, the Ethiopian Civil War and military policies taken by the Ethiopian government”. Even if the drought was totally caused by a volcanic eruption of VEI 5 (wikipedia’s page does not mention any volcanic eruption; could you link to an article?), such eruption would not be responsible for all of the famine deaths.
Some of the famine deaths would have to be attributed to the other causes, such that the deaths attributed to each cause added up to the total death toll.
VEI 5 eruptions happen once every decade or so. As a result, a naive interpretation of your statement (I am not saying you would endorse it!) would say VEI 5 eruptions cause in expectation a famine with 0.5 M deaths every decade or so. However, the expected death toll would be much lower if the other causes (Ethiopian Civil War and military policies taken by the Ethiopian government) have a much lower probability.
This is why I mentioned in my last comment that:
Similarly, the more factors are needed to cause large famines (e.g. not only a VEI 5 eruption, but also civil war, and lack of effective international assistance), the less likely they will tend to be. This effect exists unless there is a perfect correlation between all the contributing causes (e.g. if a VEI 5 eruption always caused a civil war, and lack of effective international assistance).
I agree my analysis is far from rigorous. However:
It is hopefully better to have a non-rigorous analysis plus your thorough comment than the alternative of no analysis.
I quantify my estimates for the sake of reasoning transparency.
To illustrate, I could say the nearterm annual risk of human extinction from supervolcanoes is low, but then some readers may infer from this anything ranging from 0 to maybe 0.01 %. The latter would arguably imply volcanic risk receiving way more attention from the effective alstruism community than it currently does, whereas my actual best guess of 3.38*10^-14 does not.
So I think I had better provide my best guess for the risk. At the very least, this facilitates agreement/disagreement. If I had just mentioned the extinction risk was extremely low, you may not have provided such detailed and valuable feedback due to perceived agreement.
I also think researchers quite often implicitly put numbers on metrics. For example, you said:
It seems to me that, by answering yes to your question, you are implicitly arguing that there are interventions to decrease the expected mortality of volcanic eruptions whose cost to save a life is sufficiently low for such interventions to receive more attention (e.g. more research like yours on volcanic risk). Moreover, if by “we” you mean not just the world as a whole, but funders aligned with effective alstruism too (namely, Open Philanthropy), you may be implicitly claiming that such interventions can have a cost to save a life lower than 5 k$ (that of GiveWell’s top charities). I think it would be great if someone (maybe you and Lara!) published in a peer-reviewed journal a standard cost-effectiveness analysis of the interventions you think are being overlooked.