In other words, both the kaboom and the KABOOM must be initiated by Putin and have no upsides for him. That’s two huge hurdles to Armageddon, and I find your probability estimates overly pessimistic.
If Putin uses a nuke in Ukraine, NATO will respond by decimating the Russian invasion force in Ukraine (probably excluding Crimea) with conventional air power. That should be seen as de-escalating, since 1) only a nuclear response can really be an escalation to a nuclear provocation, and 2) Russia’s pre-war border is not violated. It will allow the Ukrainians to take back their land to pre-war boundaries (“Vietnam”). Putin knows this (it’s probably been “explained” to him by Western leaders), so the likelihood he would choose that path is small. Even if he does, I think the likelihood he would opt for further nuclear escalation with a first strike beyond Ukraine is much smaller than you claim. The West would never opt for a nuclear first strike, because of their clear conventional advantage.
I suppose it boils down to what you include when you say "mind". I think the part of our mind that talks and writes is not very different from the part that thinks. So, if you narrowly, but reasonably, define the "mind" as only the conscious, thinking part of our personality, it might not be so farfetched to think a reasonable reconstruction of it from writings is possible.
Thought and language are closely related. Ask yourself: How many of my thoughts could I put into language, given a good effort? My gut feeling is "most of them", but I could be wrong. The same goes for memories. If a memory can not be expressed, can it even be called a memory?
Yes, making them would be incredibly hard, and because of their relatively short lifetimes, it would be extremely surprising to find any lying around somewhere. Atom sized black holes would be very heavy and not produce much Hawking readiation, as you say. Smaller ones would produce more Hawking radiation, be even harder to feed, and evaporate much faster.
The task you describe, at least the part where no whole brain transplant is involved, can be divided into two parts: 1) extracting the essential information about your mind from your brain, and 2) implanting that same information back into another brain.
Either of these could be achieved in two radically different ways: a) psychologically, i.e. by interview or memoir writing on the extraction side and "brain-washing" on the implanting side, or b) technologically, i.e. by functional MRI, electro-encephalography, etc on the extraction side. It is hard for me to envision a technological implantation method.
Either way, it seems to me that once we understand the mind enough to do any of this, it will turn out the easiest to just do the extraction part and then simulate the mind on a computer, instead of implanting it into a new body. Eliminate the wetware, and gain the benefit of regular backups, copious copies, and Moore's law for increasing effectiveness. Also, this would be ethically much more tractable.
It seems to me this could also be the solution to the unfriendly AI problem. What if the AI are us? Then yielding the world to them would not be so much of a problem, suddenly.
You might want to check out Centauri Dreams, best blog ever and dedicated to this issue.
Throwing mass into a black hole is harder than it sounds. Conveniently sized black holes that you actually would have a chance at moving around are extremely small, much smaller than atoms, I believe. I think they would just sit there without eating much, despite strenous efforts at feeding them. The cross-section is way too small.
To make matters worse, such holes would emit a lot of Hawking radiation, which would a) interfere with trying to feed them, and b) quickly evaporate them ending in an intense flash of gamma rays.
Hah, thanks for pointing this out. I must have read or heard of this before and then forgotten about it, except in my subconscious. Looks like they have done the math, too, and it figures. Cool!
Well, this is not pumping, but it might be much more efficient: As I understand, the polar ice caps are in an equilibrium between snowfall and runoff. If you could somehow wall in a large portion of polar ice, such that it cannot flow away, it might rise to a much higher level and sequester enough water to make a difference in sea levels. A super-large version of a hydroelectric dam, in effect, for ice.
It might also help to have a very high wall around the patch to keep air from circulating, keeping the cold polar air where it is and reduce evaporation/sublimation.
I think you have something there. You could design a complex, but at least metastable orbit for an asteroid sized object that, in each period, would fly by both Earth and, say, Jupiter. Because it is metastable, only very small course corrections would be necessary to keep it going, and it could be arranged such that at every pass Earth gets pushed out just a little bit, and Jupiter pulled in. With the right sized asteroid, it seems feasible that this process could yield the desired results after billions of years.