Public debt is a side show. Private debt is the economy killing problem. Once you resolve individual monetary scarcity, systemic austerity and inflation with the dual 50% discount policies fiscal spending will become even less of a problem than it already is and the fiscal spending necessary to confront the very real ecological problems we face will also be enabled.
I have said before I suspect that after an uptick in consumption occurs with the above policies I look for people to begin saving and investing. Nevertheless, the new publicly administered non-profit national banking and financial system could create and fund ecology bonds for research into and/or creation of green technologies at interest of say 3-5% on a sliding scale if individuals put 25-50% of their savings into purchasing them thus funding and incentivizing innovative ecological sanity and curbing consumption as well.
The new monetary and financial paradigm opens up all kinds of sane and innovative possibilities.