How do Economists view the total value of the world?

I lack the jargon needed to phrase this eloquently, so bear with me while I stumble through explaining the question.

Money comes in different metrics (currencies) who's value is largely determined by 1) the governing organization that creates and destroys that currency at will (i.e. fiat currencies) and 2) supply and demand of resources (e.g. materials, labor, etc.). This is done within an isolated system (Earth, space faring species TBD) so despite the numeric values fluctuating, the available resources which these values are based on remain at or below some critical threshold achievable within the isolated system.

Is this being accounted for in modern times? Are we just ignoring it and allowing practical resource constraints to go unmitigated, absorbing the volatility that creates until it stabilizes?