Less Disaster

The last great catastrophe probably wasn’t as bad as we’d thought:

Toba is a supervolcano … eruption, 74,000 years ago, … Releasing 2500 cubic kilometres of magma – nearly twice the volume of mount Everest … the largest eruption on Earth in the last 2 million years … Previous computer models … suggested global temperatures dropped by about 10 °C following the blast.  This supports the idea of a decade-long “volcanic winter” and widespread catastrophe. … Modern humans, … would have been whittled down to just a few thousand breeding pairs scattered in dispersed refugia. …

Graf and his colleagues suggest a new estimate of global cooling of just 2.5 °C, which lasted for just a few years. … In places like India the average temperatures may only have fallen by about 1 °C. …

Recent archaeological and geological work in India seems to support Graf’s claims. .. Had there been a sudden deforestation event … topsoil no longer anchored by trees would be expected to wash down into valleys. … “We don’t find a rapid influx of soil arriving on top of the ash layers.” … [A] hunter-gatherer camp … has yielded more than 1800 tools, … hominin life appeared to continue in the same vein immediately after the eruption, with hundreds more stone tools in the layers immediately above the ash fall.  The team uncovered a similar story 1000 kilometres further north … “We see very little change in tool technology across the Toba ash.”

If last near-existential disaster wasn’t as bad as we’d thought, maybe our existential risk is a bit less than we’d thought.  Not big news, but good news even so.

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  • Jess Riedel

    How do the details of a historical volcanic eruption change our estimates of future existential risk?

    • Proper Dave

      I agree, natural existential risks is extremely rare, highly speculative (gamma ray bursters) and in many cases if it really exists completely non preventable.

      You can prepare for disasters and should although some ignore it deliberately like in the case of Katrina.

      The biggest threat is of course human induced and that is controllable and conceivably preventable.

      So I have no problem with the findings but finds Robin’s “conclusion” predictable. Another reason in his mind to do nothing…

      Except while there is no credible natural existential risks there is not just credible potential but actual existing anthropomorphic ones now.

  • kurt9

    I have noticed that any disaster scenario that is hyped by the legacy media is ALWAYS accompanied with calls for more regulation, more taxation, more power invested in non-elected government bureaucrats, and the required acceptance of less economic and sometimes personal freedom.

    Anyone else notice this pattern, or is it just me?

    • david

      Reality has a statist bias.

      • kurt9

        I assume you are saying that such “emergencies” are nothing more the sophistry cooked up to justify the increase of power of this or that group over everyone else. If so, I agree with you completely.

        The joke is on those who believe the sophistry, but who are not part of the power group to benefit from it personally.

    • Proper Dave

      Don’t worry its just you.

    • David C

      It’s possibly regression to the mean. If we lived in a society where more than 50% of the economy was controlled by the government, disasters might lead to arguments for less government. See China.

      But I don’t get the raise taxes part. When was the last time there was a recession and the government didn’t respond by cutting taxes?

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  • http://spacecollective.org/XiXiDu XiXiDu

    Year Without a Summer

    The Year Without a Summer (also known as the Poverty Year, Year There Was No Summer and Eighteen Hundred and Froze to Death) was 1816, in which severe summer climate abnormalities destroyed crops in Northern Europe, the Northeastern United States and eastern Canada. Average global temperatures decreased about 0.4–0.7 °C (0.7–1.3 °F), enough to cause significant agricultural problems around the globe.

    Historian John D. Post has called this “the last great subsistence crisis in the Western world”.

    Most consider the climate anomaly to have been caused by a combination of a historic low in solar activity with a volcanic winter event; the latter caused by a succession of major volcanic eruptions capped off by the Mount Tambora eruption of 1815, the largest known eruption in over 1,600 years.

    Little Ice Age

    Several causes have been proposed: cyclical lows in solar radiation, heightened volcanic activity, changes in the flow of ocean currents, an inherent variability in global climate, and decreased human populations due to the Black Death and the Columbian Exchange.


    Suppose 21st Century Disasters Like 19th Century

    We remember the 20th century because we’ve all lived in some part of it (unless of course a 9 year older is reading this) and seen lots of video about it. The century was well covered by modern media. We know less of the 19th century and some of its major natural events are not widely known.

    As compared to the 19th century the 20th century was pretty calm from the standpoint of big natural changes. What I’m going to do with this post: Imagine that the 21st century turns out to be like the 19th century in terms of the severity of climate, volcanic, and other natural events.

  • Tim Tyler

    A very long time ago -> a very small chance of it happening again soon -> don’t worry too much about it.

  • http://rhollerith.com/ Richard Hollerith

    If last near-existential disaster wasn’t as bad as we’d thought, maybe our existential risk is a bit less than we’d thought.

    If Toba had extinguished the human species, no one would have been around to update on that fact. Consequently, by the conservation of expected evidence, the fact that there are intelligent agents around to notice that Toba did not extinguish the species is not evidence about the probability that a future supervolcano will extinguish the species. In general, the fact that the aspect of reality which produces the only observers in existence has not yet been wiped out is not evidence against its being wiped out in the future — even if it had been in existence for trillions of years. In other words, a strictly outside-view analysis tells you nothing about existential risks. But surely you know that already, Robin.

    • http://rhollerith.com/ Richard Hollerith

      (Darn: no way to edit my comment.) Amendment. The fact that Toba is the largest eruption in the last 2 million years (if true) combined with substantial evidence that Toba did not harm the humans much (combined with what we know about the capacities of modern humans relative to the humans of the time of Toba) is substantial evidence that volcanos are not a significant existential risk (because in a few tens of thousands of years at the most the humans will either be immune to volcanos or will not have survived). But I still say that observational selection effects makes it less evidence than it would otherwise be.

  • Alexei Turchin

    Not true. This fact reallyshows that we underestimate frgility of human species. Because we independently know that 74 000 was bottle neck in humans diversity. So, only 1-2 C change is enough to cause near exticnction event.

    In other words, this new finding doesn’t show that supervolcanos are safer, but that shows that human are more fragile.

    • http://hanson.gmu.edu Robin Hanson

      Cites for this evidence?