We tend to assume that we must have a single, monopolistic currency, funded through bank debt, enforced by a central bank. But we don’t need any such thing! In fact, the present system is outdated, brittle and unfit for purpose (witness the eurozone crisis). Like any other monoculture, it’s profitable at first but ultimately a recipe for economic and environmental disaster. The alternative is a monetary ‘ecosystem’, with complementary currencies alongside the conventional one.