JDN 2457327

Today is Halloween, so in the spirit of the holiday I thought I’d talk about things that are scary. Not things like zombies and witches and vampires; those things aren’t real (though people do still believe in them in many parts of the world). And maybe that’s part of the point; maybe Halloween is meant to “scare” us like a roller coaster, where we feel some of the epinephrine rush of fear but deep down we know we are safe.

But today I’m going to talk about things that are actually scary, things that are not safe deep down. I could talk about the Republican debate earlier this week, but maybe I shouldn’t get too scary.

In fiction there is whatever sort of ending the author wants to make, usually a happy one. Even tragic endings are written to be meaningful and satisfying. But in real life any sort of ending is possible. I could be driving down the street tomorrow and a semi truck could blindside me and kill me on impact. There’s no satisfying tragedy there, no comeuppance for my hubris or tragic flaw in my character leading to my doom—but this sort of thing kills over 30,000 Americans each year.

But are car accidents really scary? The way they kill just about anyone at random is scary. But there is a clear limit to how much damage they can do. No society has ever been wiped off the face of the Earth because of traffic accidents. There is no way for traffic accidents to risk the survival of the human race itself.

This brings me to the first thing that is really scary: Climate change. Human societies have been wiped off the face of the Earth due to local ecological collapses. The classic example is Easter Island, which did have an ecological collapse, but also suffered greatly from European invaders. Recent evidence suggests that the Vikings fell apart because glaciation broke their trade networks. Jared Diamond argues that a large number of ancient societies have fallen due to ecological collapse.

Yet for the first time we are now facing rapid global climate change, and it is our own doing. (As the vast majority of climate scientists agree.) We are already seeing its effects in flooding, wildfires, droughts, and hurricanes. Positive feedbacks are created, such as heat waves leading to more air conditioning, which draws more electricity that releases more carbon. Even as management of fishing improves, fisheries are still being depleted—because their waters are becoming too warm for the native fish.

Just yesterday the United Nations released a report showing that current promises of reduced carbon emissions will not be sufficient—even if they are followed through, which such promises often aren’t. The goal was to keep warming under 2 C; but it looks like we are looking at more like 2.7 C. That 0.7-degree difference may not seem like much, but in fact it means thousands or even millions of additional deaths. Most of the economic damage will be done to countries near the equator—which is also where the most impoverished people tend to live. The Global Humanitarian Forum estimates that global warming is already killing 300,000 people each year and causing over $100 billion in economic damage.

Meanwhile, there is a campaign of disinformation about climate change, funneled through secretive “dark money” processes (Why are these even allowed!?), including Exxon corporation, which has known for 30 years that they were contributing to climate change but actively suppressed that knowledge in order to avoid regulation. Koch Industries has also funded a great deal of climate change denialism. West Virginia recently tried to alter their science textbooks to remove references to climate change because they considered the scientific facts to be “too political”. Supposedly serious “think tanks” with conservative ideologies twist data in order to support their claims. Rather than be caught lying or denying science, most of the Republican presidential candidates are avoiding talking about the subject altogether.
There is good news, however: More Americans than ever recognize that climate change is real. 7% changed their minds in just the last few months. Even a lot of Republican politicians are finally coming around.

What else is scary? Nuclear war, a Black Swan. This is the most probable way humanity could destroy ourselves; the probability of nuclear war in the next 50 years has been estimated as high as 10%. Every day that goes by with nuclear weapons at the ready is like pulling the trigger in a game of Russian Roulette. We don’t really know how to estimate the probability with any precision; but even 0.1% per year would be a 10% chance over the next century.

There’s good news on this front as well: Slowly but surely, the world is disarming its nuclear weapons. From a peak of 60,000 nuclear weapons in 1986, we are now down to about 10,000. But we shouldn’t get too comfortable, as the estimated number necessary to trigger a global nuclear winter with catastrophic consequences is only about 100. India or Pakistan alone probably has enough to do that. The US or Russia has enough to do it 40 times over. We will need to continue our current disarmament trend for another 30 years before no single nation has enough weapons to trigger a nuclear winter.

Then there’s one more class of scary Black Swans: Mass extinction events. In particular, I’m talking about the Yellowstone Supervolcano, which could erupt at any moment, and the possibility of a large asteroid impact which could destroy cities or even wipe out all life on the surface of the Earth. We are 99.989% sure that TV135 will not do this; but in that 0.02% chance, it would hit with the force of 2500 megatons—50 times larger than any nuclear weapon ever built. Smaller (“smaller”) sub-megaton impacts are actually remarkably common; we average about two per year. If one ever hit a major city, it would be comparable to the Hiroshima nuclear bombing. The Yellowstone supervolcano would not be as catastrophic as a planet-scouring impact, but it would be comparable to a nuclear war and nuclear winter.

With asteroids, there are actually clear things we could do to improve our chances. Above all, we could invest in space exploration and astronomy. With better telescopes and more tracking stations we could see them coming; with better long-range rockets we might be able to deflect them before they get here. A number of different deflection proposals are being studied right now. This is actually the best reason I can think of to keep at least some nuclear weapons on standby; a large nuclear blast positioned at the right place could be effective at destroying an asteroid or deflecting it enough to miss us.

With Yellowstone, there really isn’t much we can do; all we can do at this point is continue to research the supervolcano and try to find ways to reduce the probability of its eruption. It is currently estimated at a just over 1 in 1 million chance of erupting any given year, but that’s a very rough estimate. Fracking near Yellowstone is currently banned, and I think it should stay that way until we have a very clear idea of what would happen. (It’s actually possible it could reduce the probability of eruption, in which case we should start fracking like crazy.)

Forget the zombie apocalypse. I’m scared of the supervolcano apocalypse.