John - you are right of course, establishing global taxation certainly feels a long way off at present, as does disbursing money around the globe every month without issues. But basic income as an idea within nations seemed utopian five years ago, and now everyone is talking about it. Times change...
If we are ever to achieve even the vaguest semblance of economic justice between nations (rather than just within them), we will need to invent some forms of redistribution from rich to poor. A world basic income would be a highly egalitarian and corruption-proof way of doing that. Putting in place the collection mechanisms would be a huge challenge, but proposals for carbon taxes and financial transaction taxes are already well-progressed, and prominent economists have put global capital taxes on the agenda. There are already stacks of global systems and agreements in operation that transfer resources around - the WTO, IMF, etc etc. Global taxation of global corporations or transactions is surely not so different?
Regarding how the scheme would be administered, at the moment we envisage that a global entity (a branch of the UN, World Bank, ILO - whichever was the best fit, or a new one if needed) would collaborate with each national government over identification requirements and so on, but would disburse the money directly from itself to citizens, probably using new-ish technologies such as mobile money where bank account coverage is low. Again, that is new and radical, and would certainly be resisted by some governments, but we imagine that significant political pressure from citizens to be allowed their entitlement would help to nudge the thing forward. If the world wanted to give everyone that I know some free money every month, but the UK government was refusing to allow it, I imagine they might reallocate their votes. In democratic states this might do the trick, and even dictators can get toppled when their self-interest is so glaring.
These are big challenges for sure. The very purpose of the World Basic Income organisation is to begin to pull together research on potential solutions to such challenges, and to begin the long slow process of mobilising support for this idea. We are well aware it won't be easy - but imagine what it could achieve if we manage it! Similar organisations are getting started elsewhere too - Japan, Germany, The Netherlands - so we're not alone in getting the wheels in motion.