>Do you seriously think that any of the following global political challenges:
>
> - convince everyone on Earth to implement changes that are bad for them, like not eating animal-based foods, with only the promise of "maybe in 200 years your descendants, should your line not be extinct by then, will benefit" as compensation
Even if we assume that people are as self-centered as you portray them, eating meat is not necessarily good for you:
http://www.cancer.org/cancer/news/world-health-organization-...
> - reorganise every single human settlement and/or social structure on Earth to put people closer to their workplaces
Most of the world actually already lives like this. Yes, the urban sprawl of many American cities will have to go, but it can (and will) be done.
> - implement a global wealth redistribution scheme that doesn't start with North Korea conquering the planet through nuclear war
Such a system was implemented after WW2 (cf. https://en.wikipedia.org/wiki/Marshall_Plan). Worked out pretty well.
> - successfully convince every NWS to destroy their nukes and institute a worldwide ban on nuclear weaponry
If we elect politicians who are more interested in cooperation than in sabre-rattling, and more interested in the problems of the people they represent than in the needs of the military-industrial complex, they will have few incentives for maintaining anything even remotely the size of the current stockpile. Great though it may be, we do not need an all-out ban on nuclear weapons to ensure our continued survival, only a (large) reduction in the size of the stockpiles. That not only makes sense from a survival perspective, but also economically.
> Are easier than the engineering challenge of building a colony on Titan? If yes, please let me into whatever politics-free, single world government utopia you're living in.
My lack of cynicism may be due to the fact that I live in Europe, where I can see more progress than stagnation in all of the areas you mention above. Given how close it was that a politician who advocated all of the above policies was elected as president of the USA, I think there is reason to be optimistic there as well.