The possibility of a radiological attack (“dirty bomb”) is in the news. There is one big, important thing that everyone should understand if should such an attack occurs: DON’T PANIC. A dirty bomb would be alarming, but overreaction could make matters much worse. A dirty bomb is an explosive that spreads radioactive material. It is not a nuclear weapon—no nuclear reaction. It’s a “conventional” explosive designed to disperse radioactive material. The explosion itself may not be particularly large.

We interrupt our coverage of Ukraine & nuclear war to present to you my new research paper:

Assessing Natural Global Catastrophic Risks

Read on for some proper doomscrolling. The paper was just published in the journal Natural Hazards, dx.doi.org/10.1007/s11069…

Preprint (no paywall… though for now the journal version is also not paywalled) online here:
gcrinstitute.org/assessing-natu…

Read the whole thread by @ruth_deyermond. I’ve observed the same trend regarding nuclear weapons—seen as passé, whereas climate change and now AI are the hot new global risks. Folks, the nukes still exist. As long as they do (caveat below), they demand attention & expertise.

https://twitter.com/ruth_deyermond/status/1580594918598115330

Caveat: It’s not just about the existence of nukes, but the existence of conditions in which nukes may be rebuilt. In nuclear weapons theory, one concept is to pursue not just zero nukes, but zero capacity and/or motivation to rebuild them.

There’s lots of talk about nuclear war these days, but what exactly does that mean?

This thread explains the impacts of nuclear war, from local harms to global catastrophe. It provides background & shares some of my research.

Be warned, this is not for the faint of heart. Preamble: This thread is just on the nature of the impacts, not on the ethical and policy implications. The only claim here is that it is important for us as citizens to understand the nature of the issues we are faced with. For more practical discussion:

https://twitter.com/SethBaum/status/1579077137948196864

My immediate, tentative reaction to the new Russian missile attacks: (1) a step closer to a dark endgame, though not necessarily a large step; (2) no new implications for how to reduce the risk of nuclear war.

This thread shares some experts whom I am relying on for the above. If you read one thing on Ukraine right now, read this. Understanding the other side’s thinking is very important, very difficult, and very easy to neglect. @DrRadchenko is one of the best people to help us with this.

https://twitter.com/DrRadchenko/status/1579366405454954496

So lots of people are interested in the probability of nuclear war right now.

I have studied the probability of nuclear war about as much as anyone (e.g., lead author on the model in the graphic shown below).

Here are my thoughts. 1) There isn’t going to be any clarity on how large the probability is. It’s too opaque, too complex, too fast-moving.

2) In this instance, it’s OK to lack clarity on the probability. Sound policy & decision-making can proceed regardless, and that’s the important part.

If Ukraine continues to retake territory, how can we dissuade Russia from escalating to nuclear?

Prior thread discussed international condemnation.

That’s a stick. Here, a quick attempt at listing out a wider range of carrots & sticks.

https://twitter.com/SethBaum/status/1578029034700943362

In the same spirit from @LawDavF:

https://twitter.com/LawDavF/status/1576980817359917062

For addressing climate change, what is the role of individual action? A bit of a hot topic.

In this thread, evidence of strong synergy between individual & collective action on transportation, one of the most important sectors for greenhouse gas emissions. For transportation:
* Individual action: walk/bike/transit instead of cars
* Collective action: pursue social and policy change so other people also avoid cars

Further background in the online sustainability course I helped design & teach in grad school:
e-education.psu.edu/geog30/node/346

How can we reduce the risk of the Ukraine war going nuclear?

A follow-up to prior discussion of the probability

This thread: the value of international condemnation of any nuclear attack, which strikes me as a clear win in that it may help & can’t hurt

https://twitter.com/SethBaum/status/1577670716689973249

The idea here is that if enough countries/institutions/people/etc speak out forcefully against any nuclear attack, it could shift Russia’s/Putin’s decision calculus. Would it work? I don’t know, ask Putin. But it’s hard to see any downsides (see caveat below). Might as well try.

What’s the probability of nuclear war from the war in Ukraine?

Yesterday I shared some notes on underlying fundamentals. Today, some notes on quantitative estimates.

The overall impression I get from this is “unlikely, but likely enough to be alarming”.

https://twitter.com/SethBaum/status/1577442369317658625

1) Expert comment

Nuclear security experts generally abstain from stating numeric probabilities of nuclear war (which I agree with). Their comments nonetheless provide perspective on the probability.

What’s the probability of nuclear war from the war in Ukraine?

This thread compiles notes+links on the underlying fundamentals

In sum: it looks like nuclear war is probably not imminent, but it’s a nervous moment & it seems likely to get worse before it (hopefully) gets better In other words: There probably won’t be nuclear war tomorrow or the next day. But the probability of some nuclear attack before the war ends is much higher. How high? Hard to say. But plenty high enough to make me feel rather uncomfortable to say the least.