World Basic Income has published a proposal:
A dividend from the global commons – harvesting a share for us all
Although pilot schemes for world basic income may be funded through international aid or charitable giving, we envisage that in the long term a whole-world basic income would be funded through new global mechanisms, which would aim to harvest a share of the of the wealth that our ancestors have built up over the centuries, and that the earth naturally yields now, which is known as ‘the commons’. This could be gathered through collective shareholdings in global companies, international taxes, such as a carbon extraction licence fee or financial transaction tax, royalties on goods like intellectual property or the extraction of natural resources, or fees for the use of shared goods, such as charging airlines for using our shared airspace.
Please read the full proposal here.