Well, climate change and the energy crisis will cause global instability for sure. Preparing your society to live with less energy is also a strategic objective: there will be wars for energy (but that's not new, there have been invasions for control over oil in the past), but it seems quite obvious that the more reliant your society is on fossil fuel, the harder it will be. And I would rather have countries degrow than count on the fact that their military is powerful enough to screw the others (which again would not be new).
I don't see that as a fairy tale land.