Well, "impossible" is a strong term. "Negative interest rates" as described are kind of a derivative of the situation, which has a lot to do with currency arbitrage, HFT shorting and other fiduciary hijinks whereby the world's wealthiest gamblers try to make money off chaos. I read a letter the other day that said anything with a positive value in Greece is a potential short right now because they may not have the ability to make a market in a year. An increase in the popularity of these bonds indicates an increase in the suspicion that the Eurozone is going to break up. I don't see American bonds going negative because of this, but I'm an armchair guy. I will say that if you've got a pension, negative interest rates are not your friend.
Yeah, the title says impossible, but the article gives a reasonable explanation of how it becomes possible, even without arbitrage (for the long-term Swiss ones): supply is greater than demand. If people want shelter, and there isn't enough shelter to go around, they'll risk a loss for it. Still, one could just hold their money in Euros, but maybe Euros will tank and the hope is that in such a scenario the bonds will be honored in the new currency? Odds on war in Europe?
I wouldn't hold Euros right now. I'm as much a victim of confirmation bias as anyone but from everything I read, if the Euro makes it through Greece unscathed it's still got Spain, Portugal, Italy and France to deal with and much like the Nixon Shock, it's gonna go up like the Hindenberg when it goes. There isn't going to be a lot of time to play strategically, it's gonna be Euro/No Euro in the course of an afternoon. I don't see war as a possibility. Greece is gonna default and face sanctions, but nobody's rolling troops over austerity. Russia got exactly what it wanted out of the Crimea and most of the big players are too busy dealing with their own ethnic bullshit to get belligerent over borders any time soon. If I were to predict "next shots fired" I'd guess the Chinese and the Japanese are likely to play brink-of-war games. Japan's all twitterpated over ISIS and China is feeling nationalistic. Senkaku has cooled but I'll bet it gets hot again with very little prodding. That's disregarding the semi-regular border skirmishes in Kashmir, of course.
I think you're right about war in Europe, at least I hope so. Even so, part of me (and Tolstoy) wonders if war isn't a force that we add characters and a story to. When enough countries cannot grow out of their debt, and the debt becomes untenable, we might become lemmings. I can see a desperate China punching Japan in the face. Unlike war in Europe, it would be culturally cathartic.
The Russians have always been pretty fatalistic about that shit, though. You know you've got it bad when you're better off under the Mongols. Germany didn't enter into WWII over reparations, Germany entered into WWII because WWI was a stalemate rather than a loss and they had unfinished business to attend to. I'm unaware of any unfinished business in Europe other than Cyprus. Chile and Argentina had all sorts of miserable debt problems and nobody invaded anybody else. I'll bet Japan throws the first punch. They're likely to see their standard of living continue to decline. The one problem they have is a lack of able-bodied men capable of marching...
Maybe Putin decides rebuilding the USSR is a good idea? War usually means someone wants to conquer some territory, and there doesn't seem like anyone else in Europe that would be interested in expansion. Actually, I'd bet on China taking a few islands. They do have an army, and feel like they owe it to Japan. There's a solid WWIII: Russia decides to rebuild the USSR, and China takes Taiwan and invades some of Japan. Not likely.
I'm sure he'd love to have Ukraine. I'm sure he'd love to have Kazakhstan. Most of the rest of it is a net drain. If anything, Kazakhstan might be a flashpoint; the chinese have been investing heavily in Kazakhstan and if Russia decided they wanted it back, things might get exciting.