Why not construct an IPO (initial public offering) with shares representing whole swaths of ecosystems around the world. There are plenty of ways to measure the health and economic benefit of an ecosystem. This information could be treated just as financial statements are about public companies. Thus, the creation of monetary value in stocks which represent ecosystems. These would be trading vehicles uncorrelated with other assets, traditionally “human” assets. Perfect for hedging against “human” assets which have fundamental support from human institutions.
For example: an IPO of 200 million shares representing the Amazon Rain Forest. Thus if they price at $20 per share, then the market cap of the Amazon would be $4 billion. The money raised could be put to use in various ways by a third party. This third party would be responsible for improving the ecosystem. Thus the money would go only towards preservation and building up the ecosystem. All these ideas would be further researched by people more familiar with the field of ecology.
The shares of the Amazon Ecosystem would trade almost totally uncorrelated with most traditional assets; thus allowing a new form of diversification. Some of the downsides would include the fact that other governments own these resources and make decisions independently of asset holders. Or, perhaps these securities could be designed with environmental protection in mind, i.e. a government could not change the ecosystem without approval from a board of directors controlled by the owners of the shares. Hopefully, they would make decisions in the best interest of the environment.