Green bonds are issued according to directives set by the(CBI). The CBI is an international investor-focused not for profit organization that has set the certification and assurance standards for green bonds. This helps assure investors that the proceeds are being used for the right projects.
Could this system be built over a decentralized platform. There are 2 parts to this system. The part where money is raised based on a renting activity. And the second part, where the money is used to fund projects that help the environment. A blockchain could help bring access to a larger market for raising capital. Anyone could chip in to such an initiative. The blockchain would inherently secure the transaction and keep track of where the money is routed to.